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Introduction: There are a growing number of surgical approaches for laparoscopic radical resection of right-sided colon cancer, while there are relatively few comparative analyses of the different surgical approaches. Objective: To evaluate the safety and efficacy of different surgical approaches (intermediate approach, caudolateral approach, caudolateral combined with intermediate approach) for laparoscopic radical resection of right-sided colon cancer by conducting a network meta-analysis (NMA). Method: We searched PubMed, Web of science and China National Knowledge Infrastructure (CNKI) databases. We reviewed the Chinese and English literature on controlled studies of laparoscopic radical resection of right-sided colon cancer including intermediate approach, caudolateral approach and caudolateral combined with intermediate approach, reported from the establishment of the database to September 2023. The inclusion and exclusion criteria were independently conducted by two researchers and relevant data was extracted from the qualifying literature and analyzed using Stata15 software. Results: Nine controlled studies of relevance including 715 patients were screened with right-sided colon cancer. Net meta-analysis showed that compared with the intermediate approach, the caudolateral approach was superior to the intermediate approach in terms of operation time (SMD = 0.75, 95% CI = 0.38 ~ 1.12, P = 0.0001), and bleeding volume (SMD = 1.15, 95% CI = 0.18 ~ 2.13, P = 0.002), while the difference was not statistically significant among the caudolateral approach compared with the intermediate approach in terms of the number of lymph node dissection, postoperative complication rate, time to first postoperative flatus and postoperative hospitalization. Compared with the intermediate approach, the combined approach was superior to the intermediate approach in terms of operation time (SMD = -0.87, 95% CI = -1.22 ~ -1.52, P < 0.05), bleeding volume (SMD = -1.09, 95% CI = -1.98 ~ -0.19, P < 0.05), the number of lymph node dissection (SMD = 0.21, 95% CI = 0.01 ~ 0.41, P < 0.05), and postoperative complication rate (RR = 2.24, 95% CI = 1.21 ~ 4.13, P < 0.05), while the difference was no statistically significant among the combined approach compared with the intermediate approach in terms of time to first postoperative flatus and postoperative hospitalization. Compared with the caudolateral approach, there was no statistically significant difference between the caudolateral approach and the combined approach in terms of operation time, bleeding volume, the number of lymph node dissection, postoperative complication rate, time to first postoperative flatus and postoperative hospitalization. According to the results of the surface under the cumulative ranking curve (SUCRA), the caudolateral approach and the combined approach were superior to the intermediate approach in terms of operation time (SUCRA: 65.1%, 84.9%, 0), bleeding volume (SUCRA: 77%, 71.9%, 1%), the number of lymph node dissection (SUCRA: 49.6%, 90.8%, 9.7%), postoperative complication rate (SUCRA: 46.6%, 97.5%, 5.9%), time to first postoperative flatus (SUCRA: 67%, 77.8%, 5.2%), postoperative hospitalization (SUCRA: 30.8%, 96.4%, 22.8%). Conclusion: The caudolateral combined with intermediate approach and the caudolateral approach are safer and more effective than the intermediate approach. According to the results of SUCRA, the combined approach is superior to the caudolateral approach in terms of operation time, the number of lymph node dissection, postoperative complication rate, time to first postoperative flatus and postoperative hospitalization, the caudolateral approach is superior to the combined approach in term of bleeding volume. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to evaluate the short‑ and long‑term outcomes of single‑incision laparoscopic colectomy (SILC) for right‑sided colon cancer (CC) using a craniocaudal approach. Patients and Methods: The data of patients who underwent SILC for right‑sided CC at our hospital between January 2013 and December 2022 were retrospectively collected. Surgery was performed using a craniocaudal approach. Short‑ and long‑term operative outcomes were analysed. Results: In total, 269 patients (127 men, 142 women; median age 74 years) underwent SILC for right‑sided CC. The cases included ileocaecal resection (n = 138) and right hemicolectomy (n = 131). The median operative time was 154 min, and the median operative blood loss was 0 ml. Twenty‑seven cases (10.0%) required an additional laparoscopic trocar, and 9 (3.3%) were converted to open surgery. The Clavien–Dindo classification Grade III post‑operative complications were detected in 7 (2.6%) cases. SILC was performed by 25 surgeons, including inexperienced surgeons, with a median age of 34 years. The 5‑year cancer‑specific survival (CSS) was 96.1% (95% confidence interval [CI] 91.3%–98.2%), and CSS per pathological disease stage was 100% for Stages 0–I and II and 86.2% (95% CI 71.3%–93.7%) for Stage III. The 5‑year recurrence‑free survival (RFS) was 90.6% (95% CI 85.7%–93.9%), and RFS per pathological disease stage was 100% for Stage 0–I, 91.7% (95% CI 80.5%–96.6%) for Stage II and 76.1% (95% CI 63.0%–85.1%) for Stage III. Conclusions: SILC for right‑sided CC can be safely performed with a craniocaudal approach, with reasonable short‑ and long‑term outcomes. [ABSTRACT FROM AUTHOR]

Aim: Intracorporeal anastomosis (IA) is becoming increasingly popular and replacing extracorporeal anastomosis (EA) for reconstruction in laparoscopic and robotic surgery for right‐sided colon cancer (LSRCC). Intracorporeal overlap anastomosis (IOA) is the most widely used IA technique. This study aimed to examine the safety of IOA by investigating its short‐term results during the implementation phase. Methods: This multicenter prospective cohort study was conducted by the Kanagawa Yokohama Colorectal Cancer (KYCC) Study Group. Patients with stage 1–3 colon cancer who planned to undergo LSRCC with IOA reconstruction were eligible. The incidence of anastomotic leakage (AL) of Clavien–Dindo (C–D) grade ≥3 was evaluated as the primary endpoint, and other surgical outcomes and postoperative complications of C–D grades ≥2 were the secondary endpoints. Results: A total of 127 patients were enrolled, of whom 120 were finally analyzed. The incidence of C–D grade ≥2 complications was 8.3%. The incidence of C–D grade ≥3 AL was 0.8%. This trend was lower than that reported in previous randomized controlled trials (RCTs) and acceptable. Additionally, 1.7% of the patients developed abdominal abscesses, and no cases of anastomotic stenosis were observed. The median operative time was 257 min, and the reconstruction procedure required 32 min. Stapler closure of the enterotomy and facility experience of more than 30 cases were associated with a shorter reconstruction time during IOA. Conclusion: IOA is feasible and can be safely performed during the implementation phase in patients undergoing LSRCC. [ABSTRACT FROM AUTHOR]

Abstract Introduction There are a growing number of surgical approaches for laparoscopic radical resection of right-sided colon cancer, while there are relatively few comparative analyses of the different surgical approaches. Objective To evaluate the safety and efficacy of different surgical approaches (intermediate approach, caudolateral approach, caudolateral combined with intermediate approach) for laparoscopic radical resection of right-sided colon cancer by conducting a network meta-analysis (NMA). Method We searched PubMed, Web of science and China National Knowledge Infrastructure (CNKI) databases. We reviewed the Chinese and English literature on controlled studies of laparoscopic radical resection of right-sided colon cancer including intermediate approach, caudolateral approach and caudolateral combined with intermediate approach, reported from the establishment of the database to September 2023. The inclusion and exclusion criteria were independently conducted by two researchers and relevant data was extracted from the qualifying literature and analyzed using Stata15 software. Results Nine controlled studies of relevance including 715 patients were screened with right-sided colon cancer. Net meta-analysis showed that compared with the intermediate approach, the caudolateral approach was superior to the intermediate approach in terms of operation time (SMD = 0.75, 95% CI = 0.38 ~ 1.12, P = 0.0001), and bleeding volume (SMD = 1.15, 95% CI = 0.18 ~ 2.13, P = 0.002), while the difference was not statistically significant among the caudolateral approach compared with the intermediate approach in terms of the number of lymph node dissection, postoperative complication rate, time to first postoperative flatus and postoperative hospitalization. Compared with the intermediate approach, the combined approach was superior to the intermediate approach in terms of operation time (SMD = -0.87, 95% CI = -1.22 ~ -1.52, P

Abstract Aim Intracorporeal anastomosis (IA) is becoming increasingly popular and replacing extracorporeal anastomosis (EA) for reconstruction in laparoscopic and robotic surgery for right‐sided colon cancer (LSRCC). Intracorporeal overlap anastomosis (IOA) is the most widely used IA technique. This study aimed to examine the safety of IOA by investigating its short‐term results during the implementation phase. Methods This multicenter prospective cohort study was conducted by the Kanagawa Yokohama Colorectal Cancer (KYCC) Study Group. Patients with stage 1–3 colon cancer who planned to undergo LSRCC with IOA reconstruction were eligible. The incidence of anastomotic leakage (AL) of Clavien–Dindo (C–D) grade ≥3 was evaluated as the primary endpoint, and other surgical outcomes and postoperative complications of C–D grades ≥2 were the secondary endpoints. Results A total of 127 patients were enrolled, of whom 120 were finally analyzed. The incidence of C–D grade ≥2 complications was 8.3%. The incidence of C–D grade ≥3 AL was 0.8%. This trend was lower than that reported in previous randomized controlled trials (RCTs) and acceptable. Additionally, 1.7% of the patients developed abdominal abscesses, and no cases of anastomotic stenosis were observed. The median operative time was 257 min, and the reconstruction procedure required 32 min. Stapler closure of the enterotomy and facility experience of more than 30 cases were associated with a shorter reconstruction time during IOA. Conclusion IOA is feasible and can be safely performed during the implementation phase in patients undergoing LSRCC.

Abstract Background The cranial-caudal-medial approach (CCMA) has been proposed for laparoscopic right hemicolectomy nowadays. This study aimed to investigate the safety and oncological efficacy of CCMA in the treatment of right-sided colon cancer compared to the medial–lateral approach (MLA). Methods Patients diagnosed with right-sided colon cancer were included from February 2015 to June 2018, retrospectively, dividing into the CCMA group and the MLA group. We compared the basic characteristics and the short-term and long-term outcomes in two groups. Results Two hundred and ninety-six patients were included in this study. The baseline characteristics were similar in two groups. Compared with MLA group, CCMA group exhibited shorter operation time (136.3 ± 25.3 min vs. 151.6 ± 21.5 min, P

Background: The cranial-caudal-medial approach (CCMA) has been proposed for laparoscopic right hemicolectomy nowadays. This study aimed to investigate the safety and oncological efficacy of CCMA in the treatment of right-sided colon cancer compared to the medial–lateral approach (MLA). Methods: Patients diagnosed with right-sided colon cancer were included from February 2015 to June 2018, retrospectively, dividing into the CCMA group and the MLA group. We compared the basic characteristics and the short-term and long-term outcomes in two groups. Results: Two hundred and ninety-six patients were included in this study. The baseline characteristics were similar in two groups. Compared with MLA group, CCMA group exhibited shorter operation time (136.3 ± 25.3 min vs. 151.6 ± 21.5 min, P < 0.001), lower estimated blood loss (44.1 ± 15.2 ml vs. 51.4 ± 26.9 min, P = 0.010), and more harvested lymph nodes (18.5 ± 7.1 vs. 16.5 ± 5.7, P = 0.021). The 5-year overall survival (OS) rate for the CCMA group was 76.5%, and the 5-year disease-free survival (DFS) rate was 72.3%, both of which were not inferior to the MLA group. No significant difference was found between two groups in terms of other clinical parameters. Conclusion: The CCMA in laparoscopic right hemicolectomy is safe and feasible, making the anatomical plane clearer. This approach can shorten the operation time, reduce intraoperative blood loss, harvest more lymph nodes, and yield satisfactory oncological outcomes. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to develop and validate a nomogram for predicting overall survival (OS) in patients undergoing surgery for right-sided colon cancer (RCC). Methods: We collected 25,203 patients with RCC from the Surveillance, Epidemiology, and End Results (SEER) database and randomly divided them into 7:3 training and internal validation set. Utilizing the Cox proportional hazards regression model, we constructed a nomogram based on prognostic risk factors. Furthermore, for external validation, we retrospectively followed up with 228 patients from Jiaxing First Hospital and assessed and calibrated the nomogram using the C-index and calibration curves. Results: After identifying independent prognostic factors through univariate and multivariate analyses, a nomogram was developed. The c-index values of this nomogram differed as follows: 0.851 (95% CI: 0.845-0.857) in the training set, 0.860 (95% CI: 0.850-0.870) in the internal validation set, and 0.834 (95% CI: 0.780-0.888) in the external validation set, indicating the model's strong discriminative ability. Calibration curves for 1-year, 3-year, and 5-year overall survival (OS) probabilities exhibited a high level of consistency between predicted and actual survival rates. Furthermore, Decision Curve Analysis (DCA) demonstrated that the new model consistently outperformed the TNM staging system in terms of net benefit. Conclusion: We developed and validated a survival prediction model for patients with RCC. This novel nomogram outperforms the traditional TNM staging system and can guide clinical practitioners in making optimal clinical decisions. [ABSTRACT FROM AUTHOR]

Background: The modified complete mesocolic excision (mCME) procedure for right-sided colon cancer is a tailored approach based on the original complete mesocolic excision (CME) methodology. Limited studies evaluated the safety and feasibility of laparoscopic mCME using objective surgical quality assessments in patients with right colon cancer. The objectives of the PIONEER study were to evaluate oncologic outcomes after laparoscopic mCME and to identify optimal clinically relevant endpoints and values for standardizing laparoscopic right colon cancer surgery based on short-term outcomes of procedures performed by expert laparoscopic surgeons. Materials and methods: This is an ongoing prospective, multi-institutional, single-arm study conducted at five tertiary colorectal cancer centers in South Korea. Study registrants included 250 patients scheduled for laparoscopic mCME with right-sided colon adenocarcinoma (from the appendix to the proximal half of the transverse colon). The primary endpoint was 3-year disease-free survival. Secondary outcomes included 3-year overall survival, incidence of morbidity in the first 4 weeks postoperatively, completeness of mCME, central radicality, and distribution of metastatic lymph nodes. Survival data will be available after the final follow-up date (June 2024). Results: The postoperative complication rate was 12.9%, with a major complication rate of 2.7%. In 87% of patients, central radicality was achieved with dissection at or beyond the level of complete exposure of the superior mesenteric vein. Mesocolic plane resection with an intact mesocolon was achieved in 75.9% of patients, as assessed through photographs. Metastatic lymph node distribution varied by tumor location and extent. Seven optimal clinically relevant endpoints and values were identified based on the analysis of complications in low-risk patients. Conclusions: Laparoscopic mCME for right-sided colon cancer produced favorable short-term postoperative outcomes. The identified optimal clinically relevant endpoints and values can serve as a reference for evaluating surgical performance of this procedure. [ABSTRACT FROM AUTHOR]

BackgroundDistinct clinical features and molecular characteristics of left-sided colon cancer (LCC) and right-sided colon cancer (RCC) suggest significant variations in their tumor microenvironments (TME). These differences can impact the efficacy of immunotherapy, making it essential to investigate and understand these disparities.MethodsWe conducted a multi-omics analysis, including bulk RNA sequencing (bulk RNA-seq), single-cell RNA sequencing (scRNA-seq), and whole-exome sequencing (WES), to investigate the constituents and characteristic differences of the tumor microenvironment (TME) in left-sided colon cancer (LCC) and right-sided colon cancer (RCC).ResultDeconvolution algorithms revealed significant differences in infiltrated immune cells between left-sided colon cancer (LCC) and right-sided colon cancer (RCC), including dendritic cells, neutrophils, natural killer (NK) cells, CD4 and CD8 T cells, and M1 macrophages (P < 0.05). Notably, whole-exome sequencing (WES) data analysis showed a significantly higher mutation frequency in RCC compared to LCC (82,187/162 versus 18,726/115, P < 0.01). Single-cell analysis identified predominant tumor cell subclusters in RCC characterized by heightened proliferative potential and increased expression of major histocompatibility complex class I molecules. However, the main CD8 + T cell subpopulations in RCC exhibited a highly differentiated state, marked by T cell exhaustion and recent activation, defined as tumor-specific cytotoxic T lymphocytes (CTLs). Immunofluorescence and flow cytometry results confirmed this trend. Additionally, intercellular communication analysis demonstrated a greater quantity and intensity of interactions between tumor-specific CTLs and tumor cells in RCC.ConclusionRCC patients with an abundance of tumor-specific cytotoxic T lymphocytes (CTLs) and increased immunogenicity of tumor cells in the TME may be better candidates for immune checkpoint inhibitor therapy.

Simple Summary: This study aimed to assess the short- and long-term survival of elderly (≥75 years old) CRC patients. Survival was analyzed according to tumor location, cancer stage, and age group. Our results showed that CRC survival among elderly patients with localized or locally advanced disease is generally good when considering the age of patients. In particular, the 75–79 and 80–84 age groups exhibited fairly good survival when compared with younger age groups. The long-term overall survival of patients aged ≥ 85 was, as expected, worse than in younger patients. However, the postoperative short-term survival for patients eligible for surgery was good, taking into account that we also included emergency procedures. These findings emphasize the importance of optimizing care for elderly CRC patients. This population-based registry study aimed to report 30-day and one-year postoperative survival, five-year overall survival (OS), and disease-specific survival (DSS) among elderly (≥75 years old) colorectal cancer (CRC) patients. All new colorectal cancer cases from 2006–2015 were included and followed until death or the end of follow-up (end of 2016). Among 27,088 CRC patients, 11,306 patients were ≥75 years old. Among patients ≥ 75 years, 36.8% (n = 4160) had right-sided colon cancer, 21.9% (n = 2478) left-sided colon cancer, and 32.3% (n = 3650) rectal cancer. In this study population, 932 patients were aged ≥ 90. The 30-day postoperative OS for patients aged 75–79 was 96.1% (95% confidence interval [CI] 95.3–96.9) falling to 93.2% (95% CI 92.0–94.4) for patients aged 80–84. The one-year postoperative OS among patients aged 75–79 was 86.3% (95% CI 84.7–87.9) compared with 80.5% (95% CI 78.7–82.3) among patients aged 80–84. Five-year OS among patients aged 75–79 was 47.6% (95% CI 46.0–49.2) and 36.6% (95% CI 34.8–38.4) among patients aged 80–84, compared with 61.7% (95% CI 60.9–62.5) among younger patients (<75 years old). Survival among elderly CRC patients (≥75 years old) was in general fairly good when compared with younger patients, especially among patients aged 75–79 and 80–84 with localized or locally advanced disease. [ABSTRACT FROM AUTHOR]

The definition of early recurrence (ER) for right-sided colon cancer patients after complete mesocolic excision (CME) with D3 lymphadenectomy remains unclear. This study aimed to define the optimal time for ER and clarify risk factors for ER and post-recurrence survival (PRS). A total of 578 right-sided colon cancer patients who underwent CME with D3 lymphadenectomy were included. The minimum p value method was used to evaluate theme optimal time of recurrence-free survival to discriminate between ER and late recurrence (LR). Risk factors for ER were determined by a logistics regression model. The PRS was compared between ER and LR. The optimal time to define ER was 15 months (P = 1.8697E−7). 93 patients developed tumor recurrence, 46 patients had ER (≤15 months) and 47 patients had LR (>15 months). Preoperative serum CA19-9 > 37 U/mL (OR = 3.185, P = 0.001), pathological N+ stage (OR = 3.042, P = 0.027), and lymphovascular invasion (OR = 2.182, P = 0.027) were identified as independent risk factors associated with ER. Age > 75 years (HR = 1.828, P = 0.040), pathological N2 stage (HR = 1.850, P = 0.009), multiple sites of recurrence (HR = 1.680, P = 0.024), and time to recurrence ≤15 months (HR = 2.018, P = 0.043) were significantly associated with worse PRS in patients with recurrence. 15 months was the optimal time to distinguish ER and LR. ER was associated with a poor PRS. Elevated preoperative serum CA19-9 level, pathological N+ stage, and lymphovascular invasion were significantly predictive of ER. [ABSTRACT FROM AUTHOR]

The clinical, histological, and molecular differences between right-sided colon cancer (RCC) and left-sided colon cancer (RCC) have received considerable attention. Over the past decade, many articles have been published concerning the association between primary tumor location (PTL) of colorectal cancer and survival outcomes. Therefore, there is a growing need for an updated meta-analysis integrating the outcomes of recent studies to determine the prognostic role of right vs left-sidedness of PTL in patients with colorectal cancer. We conducted a comprehensive database review using PubMed, SCOPUS, and Cochrane library databases from February 2016 to March 2023 for prospective or retrospective studies reporting data on overall survival (OS) and cancer-specific survival (CSS) of RCC compared with LCC. A total of 60 cohort studies comprising 1,494,445 patients were included in the meta-analysis. We demonstrated that RCC is associated with a significantly increased risk of death compared with LCC by 25% (hazard ratio (HR), 1.25; 95% confidence interval (CI), 1.19–1.31; I2 = 78.4%; Z = 43.68). Results showed that patients with RCC have a worse OS compared with LCC only in advanced stages (Stage III: HR, 1.275; 95% CI 1.16–1.4; P = 0.0002; I2 = 85.8%; Stage IV: HR, 1.34; 95% CI 1.25–1.44; P < 0.0001; I2 = 69.2%) but not in primary stages (Stage I/II: HR, 1.275; 95% CI 1.16–1.4; P = 0.0002; I2 = 85.8%). Moreover, a meta-analysis of 13 studies including 812,644 patients revealed that there is no significant difference in CSS between RCC and LCC (HR, 1.121; 95% CI 0.97–1.3; P = 0.112). Findings from the present meta-analysis highlight the importance of PTL in clinical decision-making for patients with CRC, especially in advanced stages. We provide further evidence supporting the hypothesis that RCC and LCC are distinct disease entities that should be managed differently. [ABSTRACT FROM AUTHOR]

Abstract Background The lymph node metastasis rate in right‐sided colon cancer is unknown, and the optimal central vascular ligation level remains controversial. We aimed to determine the lymph node metastasis rate and short‐term results of radical surgery with extended lymph node dissection in right‐sided colon cancer. Methods This prospective multicenter observational study included patients with stage II/III right‐sided colon cancer from five cancer hospitals. The metastasis rate of each node station was analyzed according to tumor location and main feeding artery. Results Between April 2018 and August 2021, 208 patients underwent dissection around the superior mesenteric artery (SMA) and vein (SMV). In transverse colon cancer, 7.5% and 2.5% of metastases occurred around the SMV and SMA at the root of the middle colic artery (MCA), respectively; 6.7% and 6.7% at the root of the right colic artery. In caecal cancer, 1.9% of metastases occurred around the SMV and 1.9% around the SMA. In ascending colon cancer, the rate was 1.1% around the SMV. Of the tumors, 17% fed mainly by the ileocolic artery had node metastases along the middle or right colic artery, as did 66.7% fed mainly by the right colic artery and 41.2% fed by the MCA (p = 0.01). Postoperative complications occurred in 42 patients (20.2%). Conclusion Routine prophylactic extended lymphadenectomy around the SMA might not be necessary in caecum and ascending colon cancer. Dissection around the SMA may be necessary in cases of transverse colon cancer or when the feeding artery is the MCA.

Abstract Objective The prevalence of early-onset colon cancer (EOCC) among individuals below the age of 50 has shown a marked upward trend in recent years. The embryology, clinical symptoms, incidence, molecular pathways, and oncologic outcomes differ between right-sided and left-sided colon cancers. However, the differences have not been fully researched in EOCC. Our study aims to develop and validate prognostic nomograms predicting overall survival (OS) and cancer-specific survival (CSS) for EOCC in different tumor locations based on the Surveillance, Epidemiology, and End Results (SEER) database. Methods Using the SEER database, a total of 5,588 patients with EOCC were extracted and divided into development and validation cohorts in a random allocation ratio of 7:3 across three groups. Univariate and multivariate Cox regression analyses were performed to identify independent prognostic factors influencing OS and CSS outcomes. These factors were then utilized to construct nomogram models. The prognostic capabilities of the three models were assessed through various evaluation metrics, including the concordance index (C-index), receiver operating characteristic (ROC) curves, calibration curves, decision curve analysis (DCA), and validation cohorts respectively. Additionally, survival curves of the low- and high-risk groups were calculated using the Kaplan–Meier method together with the log-rank test. Results Significant differences in clinical features were observed between right-sided and left-sided EOCCs, particularly in terms of OS (52 months vs 54 months) as demonstrated by Kaplan–Meier curves. Transverse-sided EOCCs exhibited clinical characteristics similar to right-sided EOCCs, suggesting a potential shared tumor microenvironment and therapeutic considerations. Advanced stage, liver metastasis, poor grade, elevated pretreatment carcinoembryonic antigen (CEA) level, chemotherapy, and perineural invasion were identified as independent prognostic factors across all three tumor locations and were incorporated into the nomogram model. Nomograms were constructed to predict the probability of 3- and 5-year OS and CSS. The C-index and calibration plots showed that the established nomograms had good consistency between actual clinical observations and predicted outcomes. ROC curves with calculated area under the curve (AUC) values exceeded 0.8 for all three groups in both the development and validation cohorts, indicating robust predictive performance for OS and CSS. Furthermore, decision curve analysis (DCA) plots revealed a threshold probability range of 0.1 to 0.9, within which the nomogram model exhibited maximum benefit. Kaplan–Meier curves exhibited significant differences between the low- and high-risk groups in EOCC for all three tumor locations in OS and CSS, further validating the prognostic value of the nomogram models. Conclusions We successfully developed three precise nomogram models for EOCCs in different tumor locations, providing valuable support for clinicians in guiding clinical treatments and facilitating further prospective follow-up studies.

Abstract Introduction In Western countries, right-sided colon cancers (RSCC) present at an older age and advanced stage. Researchers believe that there is a difference between left-sided colon cancer (LSCC) and RSCC. In Uganda, however, it is unknown whether differences exist in the pathological profile between RSCC and LSCC. The aim of this study was to determine the differences in clinicopathological characteristics between RSCC and LSCC in Ugandan patients. Methodology A cross-sectional study was conducted in which colorectal adenocarcinoma formalin-fixed paraffin-embedded tissue (FFPE) blocks were obtained from 2008 to 2021. Colorectal specimens were obtained from prospectively recruited patients. In the retrospective study arm, FFPE blocks and data were obtained from the archives of pathology laboratory repositories. Parameters studied included age, sex, location of the tumour, grade, stage, lymphovascular (LVI) status, and histopathological subtype between LSCC and RSCC. Results Patients with RSCC were not older than those with LSCC (mean age, 56.3 years vs 53.5 years; p = 0.170). There was no difference in the stage between RSCC and LSCC. Poorly differentiated tumours were more commonly found in RSCC than in LSCC (18.7% vs 10.1%; p = 0.038). Moderately and poorly differentiated colonic tumours were more common with RSCC (89.3%) than with LSCC (75.1%) (p = 0.007). Younger patients had more poorly differentiated tumours than older patients (19.6% versus 8.6%; p = 0.002). LVI was more common with RSCC than with LSCC (96.8% vs 85.3%; p = 0.014). Mucinous adenocarcinoma (MAC) was more common with RSCC (15.8%) compared with LSCC (8.5%) (p = 0.056) although statistical significance was borderline. Conclusions Clinicopathological features of RSCCs tend to be different from those of LSCCs. RSCCs tend to be associated with MAC, a higher grade and LVI status compared to LSCC. LSCC and RSCC present predominantly with an advanced stage; therefore, national screening programmes for the early detection of CRC are necessary to reduce mortality in our Ugandan population.

Abstract Background Colorectal cancer (CRC) is a heterogeneous disease, with subtypes that have different clinical behaviours and subsequent prognoses. There is a growing body of evidence suggesting that right-sided colorectal cancer (RCC) and left-sided colorectal cancer (LCC) also differ in treatment success and patient outcomes. Biomarkers that differentiate between RCC and LCC are not well-established. Here, we apply random forest (RF) machine learning methods to identify genomic or microbial biomarkers that differentiate RCC and LCC. Methods RNA-seq expression data for 58,677 coding and non-coding human genes and count data for 28,557 human unmapped reads were obtained from 308 patient CRC tumour samples. We created three RF models for datasets of human genes-only, microbes-only, and genes-and-microbes combined. We used a permutation test to identify features of significant importance. Finally, we used differential expression (DE) and paired Wilcoxon-rank sum tests to associate features with a particular side. Results RF model accuracy scores were 90%, 70%, and 87% with area under curve (AUC) of 0.9, 0.76, and 0.89 for the human genomic, microbial, and combined feature sets, respectively. 15 features were identified as significant in the model of genes-only, 54 microbes in the model of microbes-only, and 28 genes and 18 microbes in the model with genes-and-microbes combined. PRAC1 expression was the most important feature for differentiating RCC and LCC in the genes-only model, with HOXB13, SPAG16, HOXC4, and RNLS also playing a role. Ruminococcus gnavus and Clostridium acetireducens were the most important in the microbial-only model. MYOM3, HOXC4, Coprococcus eutactus, PRAC1, lncRNA AC012531.25, Ruminococcus gnavus, RNLS, HOXC6, SPAG16 and Fusobacterium nucleatum were most important in the combined model. Conclusions Many of the identified genes and microbes among all models have previously established associations with CRC. However, the ability of RF models to account for inter-feature relationships within the underlying decision trees may yield a more sensitive and biologically interconnected set of genomic and microbial biomarkers.

Purpose: Minimally invasive right hemicolectomy (MIRH) is the cornerstone of treatment for patients with right-sided colon cancer. This operation has evolved during recent decades, with many innovations and improvements but this has also resulted in high variability of uptake with subsequent substantial variableness. The aim of this ongoing study is to identify current surgical variations, determine the most optimal and standardised MIRH and nationally train and implement that technique to improve short-term clinical and long-term oncological outcomes. Methods: The Right study is a national multicentre prospective interventional sequential cohort study. Firstly, current local practice was evaluated. Subsequently, a standardised surgical technique for right-sided colon cancer was determined using the Delphi consensus method, and this procedure was trained during hands-on courses. The standardised MIRH will be implemented with proctoring (implementation cohort), after which the performance will be monitored (consolidation cohort). Patients who will receive a minimally invasive (extended) right hemicolectomy for cT1-3N0-2M0 colon cancer will be included. The primary outcome is patient safety reflected in the 90-day overall complication rate according to the Clavien–Dindo classification. Secondary outcomes will include intraoperative complications, 90-day mortality rate, number of resected tumour-positive lymph nodes, completeness of mesocolic excision, surgical quality score, locoregional and distant recurrence and 5-year overall survival. A total number of 1095 patients (365 per cohort) will be included. Discussion: The Right study is designed to safely implement the best surgical practice concerning patients with right-sided colon cancer aiming to standardise and improve the surgical quality of MIRH at a national level. Trial registration: ClinicalTrials.gov: NCT04889456, May 2021. [ABSTRACT FROM AUTHOR]

Background: The lymph node metastasis rate in right‐sided colon cancer is unknown, and the optimal central vascular ligation level remains controversial. We aimed to determine the lymph node metastasis rate and short‐term results of radical surgery with extended lymph node dissection in right‐sided colon cancer. Methods: This prospective multicenter observational study included patients with stage II/III right‐sided colon cancer from five cancer hospitals. The metastasis rate of each node station was analyzed according to tumor location and main feeding artery. Results: Between April 2018 and August 2021, 208 patients underwent dissection around the superior mesenteric artery (SMA) and vein (SMV). In transverse colon cancer, 7.5% and 2.5% of metastases occurred around the SMV and SMA at the root of the middle colic artery (MCA), respectively; 6.7% and 6.7% at the root of the right colic artery. In caecal cancer, 1.9% of metastases occurred around the SMV and 1.9% around the SMA. In ascending colon cancer, the rate was 1.1% around the SMV. Of the tumors, 17% fed mainly by the ileocolic artery had node metastases along the middle or right colic artery, as did 66.7% fed mainly by the right colic artery and 41.2% fed by the MCA (p = 0.01). Postoperative complications occurred in 42 patients (20.2%). Conclusion: Routine prophylactic extended lymphadenectomy around the SMA might not be necessary in caecum and ascending colon cancer. Dissection around the SMA may be necessary in cases of transverse colon cancer or when the feeding artery is the MCA. [ABSTRACT FROM AUTHOR]

Objective: The prevalence of early-onset colon cancer (EOCC) among individuals below the age of 50 has shown a marked upward trend in recent years. The embryology, clinical symptoms, incidence, molecular pathways, and oncologic outcomes differ between right-sided and left-sided colon cancers. However, the differences have not been fully researched in EOCC. Our study aims to develop and validate prognostic nomograms predicting overall survival (OS) and cancer-specific survival (CSS) for EOCC in different tumor locations based on the Surveillance, Epidemiology, and End Results (SEER) database. Methods: Using the SEER database, a total of 5,588 patients with EOCC were extracted and divided into development and validation cohorts in a random allocation ratio of 7:3 across three groups. Univariate and multivariate Cox regression analyses were performed to identify independent prognostic factors influencing OS and CSS outcomes. These factors were then utilized to construct nomogram models. The prognostic capabilities of the three models were assessed through various evaluation metrics, including the concordance index (C-index), receiver operating characteristic (ROC) curves, calibration curves, decision curve analysis (DCA), and validation cohorts respectively. Additionally, survival curves of the low- and high-risk groups were calculated using the Kaplan–Meier method together with the log-rank test. Results: Significant differences in clinical features were observed between right-sided and left-sided EOCCs, particularly in terms of OS (52 months vs 54 months) as demonstrated by Kaplan–Meier curves. Transverse-sided EOCCs exhibited clinical characteristics similar to right-sided EOCCs, suggesting a potential shared tumor microenvironment and therapeutic considerations. Advanced stage, liver metastasis, poor grade, elevated pretreatment carcinoembryonic antigen (CEA) level, chemotherapy, and perineural invasion were identified as independent prognostic factors across all three tumor locations and were incorporated into the nomogram model. Nomograms were constructed to predict the probability of 3- and 5-year OS and CSS. The C-index and calibration plots showed that the established nomograms had good consistency between actual clinical observations and predicted outcomes. ROC curves with calculated area under the curve (AUC) values exceeded 0.8 for all three groups in both the development and validation cohorts, indicating robust predictive performance for OS and CSS. Furthermore, decision curve analysis (DCA) plots revealed a threshold probability range of 0.1 to 0.9, within which the nomogram model exhibited maximum benefit. Kaplan–Meier curves exhibited significant differences between the low- and high-risk groups in EOCC for all three tumor locations in OS and CSS, further validating the prognostic value of the nomogram models. Conclusions: We successfully developed three precise nomogram models for EOCCs in different tumor locations, providing valuable support for clinicians in guiding clinical treatments and facilitating further prospective follow-up studies. [ABSTRACT FROM AUTHOR]

Abstract Background The greater omentum is derived from the foregut, and the right hemicolon is derived from the midgut based on developmental anatomy. This study aimed to investigate whether the greater omentum should be resected in laparoscopic complete mesocolic excision based on developmental anatomy for right-sided colon cancer. Methods A total of 183 consecutive patients with right-sided colon cancer were recruited in this study between February 2020 and July 2022. Ninety-eight patients underwent standard laparoscopic complete mesocolic excision surgery (CME group). The presence of isolated tumor cells and micrometastases was detected in resected greater omentum by the HE staining and immunohistochemistry analysis. Based on developmental anatomy, laparoscopic CME surgery with greater omentum preservation (DACME group) was proposed and performed on 85 right-sided colon cancer patients. To overcome selection bias, we performed a 1:1 match between two groups using four variables: age, sex, BMI, and ASA scores. Results No isolated tumor cells and micrometastases were found in the resected greater omentum specimen in the CME group. After the propensity score, 81 pairs were balanced and analyzed. Patients in the DACME group showed shorter operative time (194.9 ± 16.4 min vs.201.5 ± 11.5 min, p = 0.002), less blood loss (23.5 ± 24.7 ml vs.33.6 ± 26.3 ml, p = 0.013), and the shorter hospital stays (9.6 ± 1.7 days vs.10.3 ± 2.0 days, p = 0.010) compared with patients in the CME group. In addition, patients in the DACME group had a lower incidence of postoperative complications (4.9% vs.14.8%, p = 0.035) than patients in the CME group. Conclusion The greater omentum should be preserved during right-sided colon cancer surgery, laparoscopic CME surgery based on developmental anatomy is technically safe and feasible for right-sided colon cancer.

RAS somatic variants are predictors of resistance to anti-EGFR therapy for colorectal cancer (CRC) and affect the outcome of the disease. Our study aimed to evaluate the frequency of RAS, with a focus on KRAS variants, and their association with tumor location and some clinicopathological characteristics in Bulgarian CRC patients. We prospectively investigated 236 patients with advanced and metastatic CRC. Genomic DNA was extracted from FFPE tumor tissue samples, and commercially available kits were used to detect RAS gene somatic mutations via real-time PCR. A total of 115 (48.73%) patients tested positive for RAS mutations, with 106 (44.92%) testing positive for KRAS mutations. The most common mutation in exon 2 was c.35G>T p.Gly12Val (32.56%). We did not find a significant difference in KRAS mutation frequency according to tumor location. However, patients with a mutation in exon 4 of KRAS were 3.23 times more likely to have a tumor in the rectum than in other locations (95% CI: 1.19–8.72, p = 0.021). Studying the link between tumor location and KRAS mutations in exon 4 is crucial for better characterizing CRC patients. Further research with larger cohorts, especially in rectal cancer patients, could provide valuable insights for patient follow-up and treatment selection. [ABSTRACT FROM AUTHOR]

Background: Complete mesocolic excision (CME) or D3 lymphadenectomy led to survival benefits for locally advanced right colon cancer, but with vague definitions in anatomy and debated surgical hazard in clinic. Aiming to achieve a precise definition of it in anatomy, we proposed laparoscopic right hemicolectomy (D3 + CME) as a novel procedure for colon cancer. However, the surgical and oncological results of this procedure in clinic were uncertain. Methods: We performed a cohort study involving prospective data collected from a single-center in China. Data from all patients who underwent right hemicolectomy between January 2014 and December 2018 were included. We compared the surgical and oncological outcomes between D3 + CME and conventional CME. Results: After implementation of exclusion criteria, a total of 442 patients were included. D3 + CME group performed better in lymph nodes harvested (25.0 [17.0, 33.8] vs. 18.0 [14.0, 25.0], P < 0.001) and the proportion of intraoperative blood loss ≥ 50 mL (31.7% vs. 51.8%, P < 0.001); no significant difference was observed in the complication rates between two groups. Kaplan–Meier analysis demonstrated that a better cumulative 5-year disease-free survival (91.3% vs. 82.2%, P = 0.026) and a better cumulative 5-year overall survival (95.2% vs. 86.1%, P = 0.012) were obtained in the D3 + CME group. Multivariate COX regression revealed that D3 + CME was an independent protective factor for disease-free survival (P = 0.026). Conclusion: D3 + CME could improve surgical and oncological outcomes simultaneously for right colon cancer compared to conventional CME. Large-scale randomized controlled trials were further required to confirm this conclusion, if possible. [ABSTRACT FROM AUTHOR]

Background: Tertiary lymphoid structures (TLS) are the lymphocyte aggregates that play a key role in the vast majority of solid tumors including colon cancer, displaying an antitumor effect under most circumstances. The heterogeneity between left- and right-sided colon cancer (LCC and RCC) encompasses various aspects, such as clinical manifestations, pathological features, and immune responses. However, the function and prognostic significance of TLS within LCC and RCC have yet to be fully understood. Methods: A retrospective analysis was performed on 2612 patients who underwent radical resection for LCC or RCC without distant metastasis in multiple medical centers. Utilizing propensity score matching, 121 patients with LCC and 121 patients with RCC were selected for the training set. An external validation set including 64 patients with LCC and 64 patients with RCC were also employed. Hematoxylin-eosin and immunohistochemical staining were used to assess TLS and the proportion of various immune cells. Clinical characteristics and prognostic values of TLS in patients with LCC and RCC were analyzed. Nomograms were constructed for LCC and RCC to predict 3-year and 5-year overall survival (OS), respectively. Results: For LCC and RCC patients, TLS was located in the interstitial region or outside the tumor tissue and mainly consisted of B cells and T cells. The TLS quantity and density in RCC were higher than those of LCC. In multivariate Cox regression analysis, TLS density (P = 0.014), vascular invasion (P = 0.019), and AJCC stage (P = 0.026) were independent prognostic factors for 5-year OS of RCC. For LCC patients, AJCC stage (P = 0.024), tumor differentiation (P = 0.001), and tumor budding (P = 0.040) emerged as independent prognostic factors for 5-year OS. Similar results were obtained in the external verification set. Separate nomograms for RCC and LCC were developed, displaying improved prediction performance compared to the AJCC 8th edition TNM staging system. Conclusions: Differences in TLS quantity and density were observed between LCC and RCC, suggesting that a nomogram based on TLS density could more effectively predict survival for RCC patients. Furthermore, a nomogram based on tumor budding was recommended for better prediction of LCC patient survival. Taken together, these results suggested that the immune and clinical characteristics of colon cancer at left and right side were substantially different, which may lead to the use of different prediction model and the development of individual treatment strategy. [ABSTRACT FROM AUTHOR]

Introduction: In Western countries, right-sided colon cancers (RSCC) present at an older age and advanced stage. Researchers believe that there is a difference between left-sided colon cancer (LSCC) and RSCC. In Uganda, however, it is unknown whether differences exist in the pathological profile between RSCC and LSCC. The aim of this study was to determine the differences in clinicopathological characteristics between RSCC and LSCC in Ugandan patients. Methodology: A cross-sectional study was conducted in which colorectal adenocarcinoma formalin-fixed paraffin-embedded tissue (FFPE) blocks were obtained from 2008 to 2021. Colorectal specimens were obtained from prospectively recruited patients. In the retrospective study arm, FFPE blocks and data were obtained from the archives of pathology laboratory repositories. Parameters studied included age, sex, location of the tumour, grade, stage, lymphovascular (LVI) status, and histopathological subtype between LSCC and RSCC. Results: Patients with RSCC were not older than those with LSCC (mean age, 56.3 years vs 53.5 years; p = 0.170). There was no difference in the stage between RSCC and LSCC. Poorly differentiated tumours were more commonly found in RSCC than in LSCC (18.7% vs 10.1%; p = 0.038). Moderately and poorly differentiated colonic tumours were more common with RSCC (89.3%) than with LSCC (75.1%) (p = 0.007). Younger patients had more poorly differentiated tumours than older patients (19.6% versus 8.6%; p = 0.002). LVI was more common with RSCC than with LSCC (96.8% vs 85.3%; p = 0.014). Mucinous adenocarcinoma (MAC) was more common with RSCC (15.8%) compared with LSCC (8.5%) (p = 0.056) although statistical significance was borderline. Conclusions: Clinicopathological features of RSCCs tend to be different from those of LSCCs. RSCCs tend to be associated with MAC, a higher grade and LVI status compared to LSCC. LSCC and RSCC present predominantly with an advanced stage; therefore, national screening programmes for the early detection of CRC are necessary to reduce mortality in our Ugandan population. [ABSTRACT FROM AUTHOR]

Background: Colorectal cancer (CRC) is a heterogeneous disease, with subtypes that have different clinical behaviours and subsequent prognoses. There is a growing body of evidence suggesting that right-sided colorectal cancer (RCC) and left-sided colorectal cancer (LCC) also differ in treatment success and patient outcomes. Biomarkers that differentiate between RCC and LCC are not well-established. Here, we apply random forest (RF) machine learning methods to identify genomic or microbial biomarkers that differentiate RCC and LCC. Methods: RNA-seq expression data for 58,677 coding and non-coding human genes and count data for 28,557 human unmapped reads were obtained from 308 patient CRC tumour samples. We created three RF models for datasets of human genes-only, microbes-only, and genes-and-microbes combined. We used a permutation test to identify features of significant importance. Finally, we used differential expression (DE) and paired Wilcoxon-rank sum tests to associate features with a particular side. Results: RF model accuracy scores were 90%, 70%, and 87% with area under curve (AUC) of 0.9, 0.76, and 0.89 for the human genomic, microbial, and combined feature sets, respectively. 15 features were identified as significant in the model of genes-only, 54 microbes in the model of microbes-only, and 28 genes and 18 microbes in the model with genes-and-microbes combined. PRAC1 expression was the most important feature for differentiating RCC and LCC in the genes-only model, with HOXB13, SPAG16, HOXC4, and RNLS also playing a role. Ruminococcus gnavus and Clostridium acetireducens were the most important in the microbial-only model. MYOM3, HOXC4, Coprococcus eutactus, PRAC1, lncRNA AC012531.25, Ruminococcus gnavus, RNLS, HOXC6, SPAG16 and Fusobacterium nucleatum were most important in the combined model. Conclusions: Many of the identified genes and microbes among all models have previously established associations with CRC. However, the ability of RF models to account for inter-feature relationships within the underlying decision trees may yield a more sensitive and biologically interconnected set of genomic and microbial biomarkers. [ABSTRACT FROM AUTHOR]

Background: Complete mesocolic excision (CME) consists of the complete removal of tumor-bearing soft tissues enveloped by the mesocolic fascia and radical lymphadenectomy at the origin of feeding vessels. We conducted a systematic review, evaluating the efficacy of the robotic CME (RCME) in patients with right-sided colon cancer and presenting the data in comparison to those concerning the open RC (right colectomy) with CME. Methods: One independent researcher searched the MEDLINE-PubMed database for published and unpublished material. Results: Eighty-three articles were found to refer to CME, 17 of which met the selection criteria following the PRISMA guidelines. All researchers presented short-term outcomes and agreed on the oncologic safety of CME. Different surgical approaches were proposed; however, no significant differences were noticed regarding the peri-operative outcomes. Conclusion: Although long-term outcomes are needed to establish it as a standard of care in right-sided colon cancer, RCME is a procedure that gains more and more grounds due to its oncologic safety. The standard medial-to-lateral approach seems to have similar results to other approaches. [ABSTRACT FROM AUTHOR]

Abstract Background Previous studies have reported that the tumor heterogeneity and complex oncogenic mechanisms of proximal and distal colon cancer (CRC) are divergent. Therefore, we aim to analyze the differences between left-sided CRC (L_cancer) and right-sided CRC (R_cancer), as well as constructing respective nomograms. Methods We enrolled 335 colon cancer patients (146 L_cancer patients and 189 R_cancer patients) from The Cancer Genome Atlas (TCGA) data sets, and 102 pairs of color cancer tissue and adjacent normal tissue (51 L_cancer patients and 51 R_cancer patients) from our hospital. Firstly, we analyzed the differences between the L_cancer patients and R_cancer patients, and then established the L_cancer and R_cancer prognostic models using LASSO Cox. Results R_cancer patients had lower survival than L_cancer patients. R_cancer patients had higher ESTIMATE and immune scores and lower tumor purity. These patterns of expression of immune checkpoint-related genes and TMB level were higher in R_cancer than in L_cancer patients. Finally, we using Lasso Cox regression analyses established a prognostic model for L_cancer patients and a prognostic model for R_cancer patients. The AUC values of the risk score for OS in L_cancer were 0.862 in the training set and 0.914 in the testing set, while those in R_cancer were 0.835 in the training set and 0.857 in the testing set. The AUC values in fivefold cross-validation were between 0.727 and 0.978, proving that the two prognostic models have great stability. The nomogram of L_cancer included prognostic genes, age, pathological M, pathological stage, and gender, the AUC values of which were 0.800 in the training set and 0.905 in the testing set. Meanwhile, the nomogram of R_cancer comprised prognostic genes, pathological N, pathological T, and age, the AUC values of which were 0.836 in the training set and 0.850 in the testing set. In the R_cancer patients, high-risk patients had a lower proportion of ‘B cells memory’, ‘Dendritic cells resting’, immune score, ESTIMATE score, immune checkpoint-related genes, and HLA-family genes, and a higher proportion of ‘T cells follicular helper’, ‘Dendritic cells activated’, and ‘Mast cells activated’. Conclusions We found significant differences between L_cancer and R_cancer patients and established a clinical predictive nomogram for L_cancer patients and a nomogram for R_cancer patients. Additionally, R_cancer patients in low-risk groups may be more beneficial from immunotherapy.

Background: The greater omentum is derived from the foregut, and the right hemicolon is derived from the midgut based on developmental anatomy. This study aimed to investigate whether the greater omentum should be resected in laparoscopic complete mesocolic excision based on developmental anatomy for right-sided colon cancer. Methods: A total of 183 consecutive patients with right-sided colon cancer were recruited in this study between February 2020 and July 2022. Ninety-eight patients underwent standard laparoscopic complete mesocolic excision surgery (CME group). The presence of isolated tumor cells and micrometastases was detected in resected greater omentum by the HE staining and immunohistochemistry analysis. Based on developmental anatomy, laparoscopic CME surgery with greater omentum preservation (DACME group) was proposed and performed on 85 right-sided colon cancer patients. To overcome selection bias, we performed a 1:1 match between two groups using four variables: age, sex, BMI, and ASA scores. Results: No isolated tumor cells and micrometastases were found in the resected greater omentum specimen in the CME group. After the propensity score, 81 pairs were balanced and analyzed. Patients in the DACME group showed shorter operative time (194.9 ± 16.4 min vs.201.5 ± 11.5 min, p = 0.002), less blood loss (23.5 ± 24.7 ml vs.33.6 ± 26.3 ml, p = 0.013), and the shorter hospital stays (9.6 ± 1.7 days vs.10.3 ± 2.0 days, p = 0.010) compared with patients in the CME group. In addition, patients in the DACME group had a lower incidence of postoperative complications (4.9% vs.14.8%, p = 0.035) than patients in the CME group. Conclusion: The greater omentum should be preserved during right-sided colon cancer surgery, laparoscopic CME surgery based on developmental anatomy is technically safe and feasible for right-sided colon cancer. [ABSTRACT FROM AUTHOR]

Abstract Background This study aimed to assess the clinical implications of the advanced lung cancer inflammation index (ALI) in patients with right-sided colon cancer (RCC) after complete mesocolic excision (CME). Methods A total of 441 patients with RCC who underwent CME were included. The optimal cut-off value for the ALI was determined using the X-tile software. Logistic and Cox regression analyses were used to identify risk factors for postoperative complications and long-term outcomes. Predictive nomograms for overall survival (OS) and disease-free survival (DFS) were constructed after propensity score matching (PSM), and their performance was assessed using the net reclassification improvement index (NRI), integrated discrimination improvement index (IDI), and time-dependent receiver operating characteristic (time-ROC) curve analysis. Results The optimal preoperative ALI cut-off value was 36.3. After PSM, ASA classification 3/4, operative duration, and a low ALI were independently associated with postoperative complications in the multivariate analysis (all P60 years, a carbohydrate antigen 19-9 (CA19-9) level >37 U/mL, pathological N+ stage, and a low ALI were independently correlated with OS (all P37 U/mL, pathological N+ stage, lymphovascular invasion, and a low ALI were independent predictors of DFS (all P

In the current era of precision oncology, it is widely acknowledged that CRC is a heterogeneous disease entity. Tumor location (right- or left-sided colon cancer or rectal cancer) is a crucial factor in determining disease progression as well as prognosis and influences disease management. In the last decade, numerous works have reported that the microbiome is an important element of CRC carcinogenesis, progression and therapy response. Owing to the heterogeneous nature of microbiomes, the findings of these studies were inconsistent. The majority of the studies combined colon cancer (CC) and rectal cancer (RC) samples as CRC for analysis. Furthermore, the small intestine, as the major site for immune surveillance in the gut, is understudied compared to the colon. Thus, the CRC heterogeneity puzzle is far from being solved, and more research is necessary for prospective trials that separately investigate CC and RC. Our prospective study aimed to map the colon cancer landscape using 16S rRNA amplicon sequencing in biopsy samples from the terminal ileum, healthy colon tissue, healthy rectal tissue and tumor tissue as well as in preoperative and postoperative stool samples of 41 patients. While fecal samples provide a good approximation of the average gut microbiome composition, mucosal biopsies allow for detecting subtle variations in local microbial communities. In particular, the small bowel microbiome has remained poorly characterized, mainly because of sampling difficulties. Our analysis revealed the following: (i) right- and left-sided colon cancers harbor distinct and diverse microbiomes, (ii) the tumor microbiome leads to a more consistent cancer-defined microbiome between locations and reveals a tumor microbiome–ileal microbiome association, (iii) the stool only partly reflects the microbiome landscape in patients with CC, and (iv) mechanical bowel preparation and perioperative antibiotics together with surgery result in major changes in the stool microbiome, characterized by a significant increase in the abundance of potentially pathogenic bacteria, such as Enterococcus. Collectively, our results provide new and valuable insights into the complex microbiome landscape in patients with colon cancer. [ABSTRACT FROM AUTHOR]

Purpose: Recently, a new certification system called the Endoscopic Surgical Skill Qualification System (ESSQS) has been launched in Japan to improve surgical safety. This study aimed to determine whether ESSQS-qualified surgeons affect the short- and long-term outcomes of laparoscopic right hemicolectomy. Methods: A total of 187 colon cancer patients who underwent laparoscopic right hemicolectomy at Kindai University Hospital between January 2016 and December 2020 were enrolled. These patients were divided into two groups based on surgeries performed by ESSQS-qualified surgeons (QS group) and non-ESSQS-qualified surgeons (NQS group). The short- and long-term outcomes were compared between the two groups before and after propensity score matching (PSM). Results: After PSM, 43 patients from each group were included in the matched cohort. In the short-term outcomes, the total operative time was significantly longer in the NQS group than in the QS group (229 vs. 174 min, p < 0.0001). However, there were no significant differences in the two groups regarding blood loss (0 vs. 0 ml, p = 0.7126), conversion (0.0% vs. 7.0%, p = 0.0779), Clavien-Dindo ≥ 2 complications (9.3% vs. 7.0%, p = 0.6933), mortality (2.3% vs. 0.0%, p = 0.3145), and postoperative hospital stay (9 vs. 9 days, p = 0.5357). In the long-term outcomes, there were no significant differences between the two groups in the 3-year overall survival (86.6% vs. 83.0%, p = 0.8361) and recurrence-free survival (61.7% vs. 72.0%, p = 0.3394). Conclusion: Laparoscopic right hemicolectomy performed by ESSQS-qualified surgeons contributed to shorter operative time. Under the supervision of ESSQS-qualified surgeons, almost equivalent safety and oncological outcomes are expected even in surgeries performed by non-ESSQS-qualified surgeons. [ABSTRACT FROM AUTHOR]

Abstract Background Some significant differences exist between the outcomes of left‐ and right‐sided colon cancer patients. The presence of nodal metastases is a critical prognostic factor, especially in the absence of distant metastasis. Our research studied the lymph nodes status of left‐ and right‐sided colon cancer patients to determine the influence of this factor on prognosis. Methods Our data were obtained from the Surveillance, Epidemiology and End Results (SEER) database. We used the chi‐square test to analyze the clinicopathological characteristics. The X‐tile program was adopted to acquire optimal cutoff points of lymph node index. Kaplan–Meier curves were used to analyze prognosis and multivariate Cox regression models were performed to identify the independent factors associated with survival. Nomograms were built to predict the overall survival of patients, Harrell's C‐index and calibration plots were used to validate the nomograms. Results The study included 189,941 patients with colon cancer without metastasis (left 69,885, right 120,056) between 2004 and 2015. There are more patients with adequate examined lymph nodes in right‐sided. Lymph node status in patients with right colon cancer has a more significant impact on the risk of death. LODDS (C‐index: 0.583; AIC: 6875.4) was used to assess lymph node status. The nomograms showed that lymph node status was the main factor to predict the outcome in right‐sided colon patients. Conclusions The influence of lymph node status on predicting prognosis is significantly different between patients with left and right colon cancer without metastasis. The tumor site needs to be considered when lymph node status is used to assess the outcome of patients.

Background: Previous studies have reported that the tumor heterogeneity and complex oncogenic mechanisms of proximal and distal colon cancer (CRC) are divergent. Therefore, we aim to analyze the differences between left-sided CRC (L_cancer) and right-sided CRC (R_cancer), as well as constructing respective nomograms.Methods: We enrolled 335 colon cancer patients (146 L_cancer patients and 189 R_cancer patients) from The Cancer Genome Atlas (TCGA) data sets, and 102 pairs of color cancer tissue and adjacent normal tissue (51 L_cancer patients and 51 R_cancer patients) from our hospital. Firstly, we analyzed the differences between the L_cancer patients and R_cancer patients, and then established the L_cancer and R_cancer prognostic models using LASSO Cox.Results: R_cancer patients had lower survival than L_cancer patients. R_cancer patients had higher ESTIMATE and immune scores and lower tumor purity. These patterns of expression of immune checkpoint-related genes and TMB level were higher in R_cancer than in L_cancer patients. Finally, we using Lasso Cox regression analyses established a prognostic model for L_cancer patients and a prognostic model for R_cancer patients. The AUC values of the risk score for OS in L_cancer were 0.862 in the training set and 0.914 in the testing set, while those in R_cancer were 0.835 in the training set and 0.857 in the testing set. The AUC values in fivefold cross-validation were between 0.727 and 0.978, proving that the two prognostic models have great stability. The nomogram of L_cancer included prognostic genes, age, pathological M, pathological stage, and gender, the AUC values of which were 0.800 in the training set and 0.905 in the testing set. Meanwhile, the nomogram of R_cancer comprised prognostic genes, pathological N, pathological T, and age, the AUC values of which were 0.836 in the training set and 0.850 in the testing set. In the R_cancer patients, high-risk patients had a lower proportion of 'B cells memory', 'Dendritic cells resting', immune score, ESTIMATE score, immune checkpoint-related genes, and HLA-family genes, and a higher proportion of 'T cells follicular helper', 'Dendritic cells activated', and 'Mast cells activated'.Conclusions: We found significant differences between L_cancer and R_cancer patients and established a clinical predictive nomogram for L_cancer patients and a nomogram for R_cancer patients. Additionally, R_cancer patients in low-risk groups may be more beneficial from immunotherapy. [ABSTRACT FROM AUTHOR]

Introduction: There are little data concerning the long-term outcome of single-incision laparoscopic surgery (SILS) for colon cancer. Therefore, we investigated not only the short-term outcomes but also the long-term outcomes of SILS for right-side colon cancer. Methods: We retrospectively compared short- and long-term outcomes of SILS and conventional laparoscopic surgery (CLS) for right-sided colon cancer in our institution. Intergroup differences of short-term outcomes were evaluated using χ2 or Fisher exact tests and 2-sample Student t tests. The disease-free survival rates (long-term outcome) of stage II and III patients were estimated using the Kaplan-Meier method and compared using log-rank tests. Results: There were 290 operations conducted for right-side (cecum and ascending) colorectal cancers from April 2011 to July 2018. Open surgery was performed in 12 cases from start to the operation. SILS was performed in 196 cases and CLS in 55 cases. One patient underwent intraoperative conversion from SILS to laparotomy for bleeding control. In addition, 1 port was added to SILS in 3 cases. These 4 cases were included in the analysis as the SILS group according to the principle of intent to treat. Background: Factors including age, gender, body mass index, performance status, and tumor stage were not statistically different between the SILS and CLS groups. In short-term outcomes, the number of harvested lymph nodes was not statistically different. SILS required less operating time (p < 0.001) and resulted in a reduced bleeding volume (p < 0.001). There was no statistical difference in the frequency of overall complications (p = 0.06). The disease-free survival of stage II and III patients was not statistically different between the 2 groups. Conclusions: With the proper adaptation of SILS by an experienced surgeon, the short- and long-term outcomes of SILS were not inferior to those of CLS. Therefore, SILS could be a treatment option for right-sided colon cancer. [ABSTRACT FROM AUTHOR]

Background: Complete mesocolic excision + D3 lymphadenectomy for right-sided colon cancer is standard procedure in Japan. A postmortem study has shown that in patients with the ileocolic artery (ICA) crossing posterior to the superior mesenteric vein (SMV), D3 lymphadenectomy may be potentially inadequate due to anatomical difficulties in lymphadenectomy of the ventral and lateral areas of the ICA. However, whether the ICA crossing pattern is associated with oncologic outcomes of right-sided colon cancer remains unclear. This study aimed to clarify whether differences in ICA crossing patterns are associated with disease-free survival and overall survival. Methods: In this retrospective study, we searched a prospectively maintained database to identify medical records of patients with right-sided colon cancer who underwent right hemicolectomy and D3 lymphadenectomy. We classified patients into two groups based on the ICA crossing pattern: ICA crossing anterior to the SMV (group A) and ICA crossing posterior to the SMV (group P). We compared oncologic outcomes between the two groups. Results: A total of 336 patients were included in the final analytic cohort: 175 in group A and 161 in group P. There was no significant difference in the number of harvested lymph nodes between the two groups. The two groups did not differ in 5-year overall survival within any disease stage. Similarly, the 5-year disease-free survival rates did not differ significantly between the two groups within any disease stage. We performed univariate and multivariate analyses, which showed the ICA crossing pattern had no clinical relevance. Conclusion: Our study did not show an association between the ICA crossing pattern and oncologic outcomes in patients with right-sided colon cancer who underwent right hemicolectomy with D3 lymphadenectomy. [ABSTRACT FROM AUTHOR]

Background: A growing body of research indicates significant differences between left-sided colon cancers (LCC) and right-sided colon cancers (RCC). Pan-immune-inflammation value (PIV) is a systemic immune response marker that can predict the prognosis of patients with colon cancer. However, the specific distinction between PIV of LCC and RCC remains unclear., Aim: To investigate the prognostic and clinical significance of PIV in LCC and RCC patients., Methods: This multicenter retrospective cohort study included 1510 patients with colon cancer, comprising 801 with LCC and 709 with RCC. We used generalized lifting regression analysis to evaluate the relative impact of PIV on disease-free survival (DFS) in these patients. Kaplan-Meier analysis, as well as univariate and multivariate analyses, were used to examine the risk factors for DFS. The correlation between PIV and the clinical characteristics was statistically analyzed in these patients., Results: A total of 1510 patients {872 female patients (58%); median age 63 years [interquartile ranges (IQR): 54-71]; patients with LCC 801 (53%); median follow-up 44.17 months (IQR 29.67-62.32)} were identified. PIV was significantly higher in patients with RCC [median (IQR): 214.34 (121.78-386.72) vs 175.87 (111.92-286.84), P < 0.001]. After propensity score matching, no difference in PIV was observed between patients with LCC and RCC [median (IQR): 182.42 (111.88-297.65) vs 189.45 (109.44-316.02); P = 0.987]. PIV thresholds for DFS were 227.84 in LCC and 145.99 in RCC. High PIV (> 227.84) was associated with worse DFS in LCC [PIV-high: Adjusted hazard ratio (aHR) = 2.39; 95% confidence interval: 1.70-3.38; P < 0.001] but not in RCC (PIV-high: aHR = 0.72; 95% confidence interval: 0.48-1.08; P = 0.114)., Conclusion: These findings suggest that PIV may predict recurrence in patients with LCC but not RCC, underscoring the importance of tumor location when using PIV as a colon cancer biomarker., Competing Interests: Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article., (©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.)

Summary: Background: D3 lymph node dissection is becoming the standard procedure for the treatment of advanced right colon cancer and has shown increasing evidence of its oncologic benefit. However, a clear indication for its application is lacking and data on this topic is unsatisfactory. Thus, the necessity for D3 lymph node dissection in clinical stage I right colon cancer remains controversial. Methods: We retrospectively analyzed data from clinical stage I right colon cancer patients who underwent radical surgery at three hospitals of Korea university medical center between January 2015 and June 2018. We compared surgical complications and short-term oncologic outcomes between D2 and D3 lymph node dissections in these patients. Results: Among 512 patients, 122 (23.8%) were clinical stage I. Of these, 88 and 34 patients received D2 and D3 lymph node dissection, respectively. There were no statistically significant differences in clinicopathologic variables and surgical outcomes between the two groups. Upstaging occurred in 16 patients (47.1%) in the D3 group and 23 patients (26.1%) in the D2 group. There were four recurrences in the D2 group but no recurrence in the D3 group. Log-rank tests showed no statistically significant difference in disease-free survival rates between the two groups (p = 0.210). Conclusion: There was no significant difference in disease-free survival rates between D2 and D3 lymph node dissection in clinical stage I right colon cancer patients. However, recurrence occurred in the D2 group. Efforts to improve the accuracy of clinical staging are required and more studies with better quality are needed.

Purpose Primary tumor location of colon cancer has been reported to affect the prognosis after curative resection. However, some reports suggested the impact was varied by tumor stage. This study analyzed the prognostic impact of the sidedness of colon cancer in stages II, III, and liver metastasis after curative resection using propensity-matched analysis. Methods Right-sided colon cancer was defined as a tumor located from cecum to splenic flexure, while any more distal colon cancer was defined as left-sided colon cancer. Patients who underwent curative resection at Nara Medical University hospital between 2000 and 2016 were analyzed. Results There were 110 patients with stage II, 100 patients with stage III, and 106 patients with liver metastasis. After propensity matching, 28 pairs with stage II and 32 pairs with stage III were identified. In the patients with stage II, overall survival (OS) and recurrence-free survival (RFS) were not significantly different for right- and left-sided colon cancers. In the patients with stage III, OS and RFS were significantly worse in right-sided colon cancer. In those with liver metastasis, OS of right-sided colon cancer was significantly worse than left-sided disease, while RFS was similar. Regarding metachronous liver metastasis, the difference was observed only in the patients whose primary colon cancer was stage III. In each stage, significantly higher rate of peritoneal recurrence was found in those with right-sided colon cancer. Conclusion Sidedness of colon cancer had a significant and varied prognostic impact in patients with stage II, III, and liver metastasis after curative resection.

RAS somatic variants are predictors of resistance to anti-EGFR therapy for colorectal cancer (CRC) and affect the outcome of the disease. Our study aimed to evaluate the frequency of RAS, with a focus on KRAS variants, and their association with tumor location and some clinicopathological characteristics in Bulgarian CRC patients. We prospectively investigated 236 patients with advanced and metastatic CRC. Genomic DNA was extracted from FFPE tumor tissue samples, and commercially available kits were used to detect RAS gene somatic mutations via real-time PCR. A total of 115 (48.73%) patients tested positive for RAS mutations, with 106 (44.92%) testing positive for KRAS mutations. The most common mutation in exon 2 was c.35G>T p.Gly12Val (32.56%). We did not find a significant difference in KRAS mutation frequency according to tumor location. However, patients with a mutation in exon 4 of KRAS were 3.23 times more likely to have a tumor in the rectum than in other locations (95% CI: 1.19–8.72, p = 0.021). Studying the link between tumor location and KRAS mutations in exon 4 is crucial for better characterizing CRC patients. Further research with larger cohorts, especially in rectal cancer patients, could provide valuable insights for patient follow-up and treatment selection.

Background: This study aimed to assess the clinical implications of the advanced lung cancer inflammation index (ALI) in patients with right-sided colon cancer (RCC) after complete mesocolic excision (CME). Methods: A total of 441 patients with RCC who underwent CME were included. The optimal cut-off value for the ALI was determined using the X-tile software. Logistic and Cox regression analyses were used to identify risk factors for postoperative complications and long-term outcomes. Predictive nomograms for overall survival (OS) and disease-free survival (DFS) were constructed after propensity score matching (PSM), and their performance was assessed using the net reclassification improvement index (NRI), integrated discrimination improvement index (IDI), and time-dependent receiver operating characteristic (time-ROC) curve analysis. Results: The optimal preoperative ALI cut-off value was 36.3. After PSM, ASA classification 3/4, operative duration, and a low ALI were independently associated with postoperative complications in the multivariate analysis (all P<0.05). Cox regression analysis revealed that an age >60 years, a carbohydrate antigen 19-9 (CA19-9) level >37 U/mL, pathological N+ stage, and a low ALI were independently correlated with OS (all P<0.05). A CA19-9 level >37 U/mL, pathological N+ stage, lymphovascular invasion, and a low ALI were independent predictors of DFS (all P<0.05). Predictive nomograms for OS and DFS were constructed using PSM. Furthermore, a nomogram combined with the ALI was consistently superior to a non-ALI nomogram or the pathological tumor-node-metastasis classification based on the NRI, IDI, and time-ROC curve analysis after PSM (all P<0.05). Conclusion: The ALI was an effective indicator for predicting short- and long-term outcomes in patients with RCC. [ABSTRACT FROM AUTHOR]

The anomalies of the middle colic artery have rarely been reported and reviewed in literature. However, in case such anomalies are observed in clinical practice, surgery must still be performed safely. This report presents the case of a 78-years-old female who underwent ileocecal resection and hepatectomy due to ascending colon cancer with liver metastasis. Preoperative abdominal contrast-enhanced computed tomography showed an anomaly of the middle colic artery. Since such anomaly is extremely rare, preoperative evaluation of vascular structure is important for safely performing the surgery.

Purpose: Anastomotic leakage after right-sided colon cancer surgery is a serious complication that affects postoperative mortality. The Charlson comorbidity index (CCI) has been reported to be a useful predictor of postoperative complications. Methods: A total of 593 cases of right-sided colon cancer resections performed from 2016 to 2020 were examined. The patients were divided into two groups according to the presence or absence of anastomotic leakage (AL, n = 28; no-AL, n = 565); clinicopathological and surgical characteristics were compared between the groups. Results: The AL group patients had a higher comorbidity rate (96.4% vs. 66.9%, p < 0.001), higher CCI score (p < 0.001), higher blood loss (42 mL vs. 23 mL, p = 0.046), and longer hospital stay (30 days vs. 12 days, p < 0.001) than the no-AL group patients. The percentages of chronic pulmonary disease (14.3% vs. 3.9%, p = 0.029), cerebrovascular disease (14.3% vs. 1.9%, p = 0.022), connective tissue disease (39.3% vs. 3.2%, p < 0.001), leukemia (3.6% vs. 0%, p = 0.042), and moderate to severe liver disease (7.1% vs. 0%, p = 0.002) were significantly higher in the AL group. In the multivariate analysis, CCI ≥ 2 was identified as an independent predictor of postoperative anastomotic leakage (hazard ratio 4.91, 95% confidence interval 2.23–10.85, p < 0.001). Conclusions: CCI could predict anastomotic leakage after right-sided colon cancer surgery. [ABSTRACT FROM AUTHOR]

Abstract Background The use of a self-expandable metallic stent (SEMS) as a bridge to surgery has increased for patients with obstructing colorectal cancer. However, relatively few reports have compared SEMS as a bridge to elective surgery for acute malignant obstruction of the right-sided colon (MORC) vs. emergency surgery (ES). This study aimed to evaluate the benefits of elective surgery after SEMS placement vs. ES for patients (including stage IV cases) with acute MORC. Methods Patients with acute MORC who underwent radical resection for a primary tumour from July 2008 to November 2016 at Zhongshan Hospital of Fudan University were retrospectively enrolled. Postoperative short-term outcomes, progression-free survival (PFS), and overall survival (OS) were compared between the SEMS and ES groups. Results In total, 107 patients with acute MORC (35 in the SEMS group and 72 in the ES group) were included for analysis. The Intensive Care Unit admission rate was lower (11.4% vs. 34.7%, P = 0.011), the incidence of complications was reduced (11.4% vs. 29.2%, P = 0.042), and the postoperative length of hospitalisation was significantly shorter (8.23 ± 6.50 vs. 11.18 ± 6.71 days, P = 0.033) for the SEMS group. Survival curves showed no significant difference in PFS (P = 0.506) or OS (P = 0.989) between groups. Also, there was no significant difference in PFS and OS rates between patients with stage II and III colon cancer. After colectomy for synchronous liver metastases among stage IV patients, the hepatectomy rates for the SEMS and ES groups were 85.7% and 14.3%, respectively (P = 0.029). The hazard ratio for colectomy alone vs. combined resection was 3.258 (95% CI 0.858–12.370; P = 0.041). Conclusion Stent placement offers significant advantages in terms of short-term outcomes and comparable prognoses for acute MORC patients. For synchronous liver metastases, SEMS placement better prepares the patient for resection of the primary tumour and liver metastasis, which contribute to improved survival.

Background: Some significant differences exist between the outcomes of left‐ and right‐sided colon cancer patients. The presence of nodal metastases is a critical prognostic factor, especially in the absence of distant metastasis. Our research studied the lymph nodes status of left‐ and right‐sided colon cancer patients to determine the influence of this factor on prognosis. Methods: Our data were obtained from the Surveillance, Epidemiology and End Results (SEER) database. We used the chi‐square test to analyze the clinicopathological characteristics. The X‐tile program was adopted to acquire optimal cutoff points of lymph node index. Kaplan–Meier curves were used to analyze prognosis and multivariate Cox regression models were performed to identify the independent factors associated with survival. Nomograms were built to predict the overall survival of patients, Harrell's C‐index and calibration plots were used to validate the nomograms. Results: The study included 189,941 patients with colon cancer without metastasis (left 69,885, right 120,056) between 2004 and 2015. There are more patients with adequate examined lymph nodes in right‐sided. Lymph node status in patients with right colon cancer has a more significant impact on the risk of death. LODDS (C‐index: 0.583; AIC: 6875.4) was used to assess lymph node status. The nomograms showed that lymph node status was the main factor to predict the outcome in right‐sided colon patients. Conclusions: The influence of lymph node status on predicting prognosis is significantly different between patients with left and right colon cancer without metastasis. The tumor site needs to be considered when lymph node status is used to assess the outcome of patients. [ABSTRACT FROM AUTHOR]

Abstract Background In recent years, the differences between left-sided colon cancer (LCC) and right-sided colon cancer (RCC) have received increasing attention due to the clinicopathological variation between them. However, some of these differences have remained unclear and conflicting results have been reported. Methods From The Cancer Genome Atlas (TCGA), we obtained RNA sequencing data and gene mutation data on 323 and 283 colon cancer patients, respectively. Differential analysis was firstly done on gene expression data and mutation data between LCC and RCC, separately. Machine learning (ML) methods were then used to select key genes or mutations as features to construct models to classify LCC and RCC patients. Finally, we conducted correlation analysis to identify the correlations between differentially expressed genes (DEGs) and mutations using logistic regression (LR) models. Results We found distinct gene mutation and expression patterns between LCC and RCC patients and further selected the 30 most important mutations and 17 most important gene expression features using ML methods. The classification models created using these features classified LCC and RCC patients with high accuracy (areas under the curve (AUC) of 0.8 and 0.96 for mutation and gene expression data, respectively). The expression of PRAC1 and BRAF V600E mutation (rs113488022) were the most important feature for each model. Correlations of mutations and gene expression data were also identified using LR models. Among them, rs113488022 was found to have significance relevance to the expression of four genes, and thus should be focused on in further study. Conclusions On the basis of ML methods, we found some key molecular differences between LCC and RCC, which could differentiate these two groups of patients with high accuracy. These differences might be key factors behind the variation in clinical features between LCC and RCC and thus help to improve treatment, such as determining the appropriate therapy for patients.

Abstract Background The introduction of complete mesocolic excision (CME) with central vascular ligation (CVL) for right-sided colon cancer has improved the oncologic outcomes. Recently, we have introduced a modified CME (mCME) procedure that keeps the same principles as the originally described CME but with a more tailored approach. Some retrospective studies have reported the favourable oncologic outcomes of laparoscopic mCME for right-sided colon cancer; however, no prospective multicentre study has yet been conducted. Methods This study is a multi-institutional, prospective, single-arm study evaluating the oncologic outcomes of laparoscopic mCME for adenocarcinoma arising from the right side of the colon. A total of 250 patients will be recruited from five tertiary referral centres in South Korea. The primary outcome of this study is 3-year disease-free survival. Secondary outcome measures include 3-year overall survival, incidence of surgical complications, completeness of mCME, and distribution of metastatic lymph nodes. The quality of laparoscopic mCME will be assessed on the basis of photographs of the surgical specimen and the operation field after the completion of lymph node dissection. Discussion This is a prospective multicentre study to evaluate the oncologic outcomes of laparoscopic mCME for right-sided colon cancer. To the best of our knowledge, this will be the first study to prospectively and objectively assess the quality of laparoscopic mCME. The results will provide more evidence about oncologic outcomes with respect to the quality of laparoscopic mCME in right-sided colon cancer. Trial registration ClinicalTrials.gov ID: NCT03992599 (June 20, 2019). The posted information will be updated as needed to reflect protocol amendments and study progress.

Abstract Background Given the differences in embryonic origin, vascular and nervous supplies, microbiotic burden, and main physiological functions of left and right colons, tumor location is increasingly suggested to dictate tumor behavior affecting pathology, progression and prognosis. Right-sided colon cancers arise in the cecum, ascending colon, hepatic flexure and/or transverse colon, while left-sided colon cancers arise in the splenic flexure, descending, and/or sigmoid colon. In contrast to prior reports, we attempt to delineate programs of tumorigenesis independently for each side. Methods Four hundred and eleven samples were extracted from The Cancer Genome Atlas-COAD cohort, based on a conservative sample inclusion criterion. Each side was independently analyzed with respect to their respective normal tissue, at the level of transcription, post-transcription, miRNA control and methylation in both a stage specific and stage-agnostic manner. Results Our results indicate a suppression of enzymes involved in various stages of carcinogen breakdown including CYP2C8, CYP4F12, GSTA1, and UGT1A within right colon tumors. This implies its reduced capacity to detoxify carcinogens, contributing to a genotoxic tumor environment, and subsequently a more aggressive phenotype. Additionally, we highlight a crucial nexus between calcium homeostasis (sensing, mobilization and absorption) and immune/GPCR signaling within left-sided tumors, possibly contributing to its reduced proliferative and metastatic potential. Interestingly, two genes SLC6A4 and HOXB13 show opposing regulatory trends within right and left tumors. Post-transcriptional regulation mediated by both RNA-binding proteins (e.g. NKRF (in left) and MSI2 (in right)) and miRNAs (e.g. miR-29a (in left); miR-155, miR181-d, miR-576 and miR23a (in right)) appear to exhibit side-specificity in control of their target transcripts and is pronounced in right colon tumors. Additionally, methylation results depict location-specific differences, with increased hypomethylation in open seas within left tumors, and increased hypermethylation of CpG islands within right tumors. Conclusions Differences in molecular mechanisms captured here highlight distinctions in tumorigenesis and progression between left and right colon tumors, which will serve as the basis for future studies, influencing the efficacies of existing and future diagnostic, prognostic and therapeutic interventions.