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Uniquely expressed in the colon, MS4A12 exhibits store-operated Ca2+ entry (SOCE) activity. However, compared to MS4A1 (CD20), a Ca2+ channel and ideal target for successful leukaemia immunotherapy, MS4A12 has rarely been studied. In this study, we investigated the involvement of MS4A12 in Ca2+ influx and expression changes in MS4A12 in human colonic malignancy. Fluorescence of GCaMP-fused MS4A12 (GCaMP-M12) was evaluated to analyse MS4A12 activity in Ca2+ influx. Plasma membrane expression of GCaMP-M12 was achieved by homo- or hetero-complex formation with no-tagged MS4A12 (nt-M12) or Orai1, respectively. GCaMP-M12 fluorescence in plasma membrane increased only after thapsigargin-induced depletion of endoplasmic reticulum Ca2+ stores, and this fluorescence was inhibited by typical SOCE inhibitors and siRNA for Orai1. Furthermore, GCaMP-MS4A12 and Orai1 co-transfection elicited greater plasma membrane fluorescence than GCaMP-M12 co-transfected with nt-M12. Interestingly, the fluorescence of GCaMP-M12 was decreased by STIM1 over-expression, while increased by siRNA for STIM1 in the presence of thapsigargin and extracellular Ca2+. Moreover, immunoprecipitation assay revealed that Orai1 co-expression decreased protein interactions between MS4A12 and STIM1. In human colon tissue, MS4A12 was expressed in the apical region of the colonic epithelium, although its expression was dramatically decreased in colon cancer tissues. In conclusion, we propose that MS4A12 contributes to SOCE through complex formation with Orai1, but does not cooperate with STIM1. Additionally, we discovered that MS4A12 is expressed in the apical membrane of the colonic epithelium and that its expression is decreased with cancer progression.

Although the safety and feasibility of conventional laparoscopic surgery (CLS) for appendiceal mucocele (AM) has been reported, studies on single-incision laparoscopic surgery (SILS) for AM have not been reported. Here, we aimed to compare the perioperative and short-term outcomes between SILS and CLS for AM and to evaluate the oncological safety of SILS. We retrospectively analyzed the medical records of patients, diagnosed based on computed tomography findings, who underwent laparoscopic surgery for AM between 2010 and 2018 at one institution. We excluded patients strongly suspected of having malignant lesions and those with preoperative appendiceal perforation. Patients were divided into two groups—CLS and SILS. Pathological outcomes and long-term results were investigated. The median follow-up period was 43.7 (range: 12.3–118.5) months. Ultimately, 116 patients (CLS = 68, SILS = 48) were enrolled. Patient demographic characteristics did not differ between the groups. The preoperative mucocele diameter was greater in the CLS than in the SILS group (3.2 ± 2.9 cm vs. 2.3 ± 1.4 cm, P = 0.029). More extensive surgery (right hemicolectomies and ileocecectomies) was performed in the CLS than in the SILS group (P = 0.014). Intraoperative perforation developed in only one patient per group. For appendectomies and cecectomies, the CLS group exhibited a longer operation time than the SILS group (63.3 ± 24.5 min vs. 52.4 ± 17.3 min, P = 0.014); the same was noted for length of postoperative hospital stay (2.9 ± 1.8 days vs. 1.7 ± 0.6 days, P

The use of an ostomy for urination and defecation leads to reduced quality of life. Although many ostomy management strategies are needed, such strategies are often implemented by patients. Thus, there is a need for a home health care service platform that can be used in ostomy patient management.We developed an ostomy patient management platform by identifying the needs of patients and medical staff through the Chronic Care Ostomy Self-Management Training Program in the United States and from studies conducted in Korea.The platform encompassed physical management, psychological management, maintenance of social function, spiritual stability, and home medical care. These components were implemented through monitoring, self-care guidance, and a community platform. For the monitoring function, a patient entered their health status in a mobile application (app); the medical staff at the affiliated hospital then monitored the stoma status through a web interface.Our platform allows medical staff to monitor ostomy patients through a web interface and help such patients to fully manage their ostomy at home using an app. We expect that the continued development of patient-oriented functions in our app will allow ostomy patients to experience quality of life improvements.

Background and objectives This study aimed to investigate the clinical course and prognostic factors after isolated local recurrence (iLR) and to identify the predictive factors for R0 resection of locally recurrent rectal cancer (LRRC). Methods We retrospectively reviewed the medical records of 76 patients with iLR who had undergone radical surgery for a primary tumor from 2003 to 2015. Results The iLR rate was 2.5%. From 76 patients, 39 patients underwent R0 resection for iLR. Multivariate analysis revealed that initial open surgery, neoadjuvant chemoradiation, and p/ypT ≥ 3 were poor prognostic factors after iLR as regard to the variables related to the primary tumor; and symptom presence at the time of iLR diagnosis, higher fixity, and no chemotherapy after iLR were associated with shorter overall survival after iLR, and R0 resection of LRRC was the only favorable prognostic factor for progression-free survival after iLR as regard to the variables related to LRRC. Higher tumor level, negative pathologic circumferential margin of the primary tumor, and low fixity of LRRC were favorable factors in achieving R0 resection of LRRC. Conclusions Early detection of iLR before symptom development, use of chemotherapy after iLR and R0 resection of LRRC should be considered to improve survival outcomes after iLR.

Background Preoperative chemoradiotherapy (PCRT) followed by surgery and adjuvant chemotherapy is the current standard treatment for stage II/III rectal cancer. However, radiotherapy in the pelvic area is commonly associated with complications such as anastomotic leakage, sexual dysfunction, and fecal incontinence. Recently, the MERCURY study showed that preoperative high-resolution magnetic resonance imaging (MRI) helped to selectively avoid PCRT. It remains unclear whether PCRT is necessary in patients who can achieve a negative circumferential resection margin (CRM) with surgery alone and in patients with cT1–2N1 or cT3N0 without CRM involvement and lateral lymph node metastasis. This study aims to evaluate the efficacy of upfront radical surgery with total mesorectal excision (TME) followed by adjuvant chemotherapy with folinic acid (or leucovorin), fluorouracil, and oxaliplatin (FOLFOX) versus the current standard treatment in patients with surgically resectable, locally advanced rectal cancer. Methods This study, named TME-FOLFOX, is a prospective, open-label, multicenter, phase II randomized trial. Patients with locally advanced rectal cancer will be randomized to receive PCRT followed by TME and adjuvant chemotherapy (arm A) or upfront radical surgery with TME followed by adjuvant FOLFOX chemotherapy (arm B). Clinical stage II/III rectal cancer without CRM involvement and lateral lymph node metastasis will be defined using preoperative MRI. The primary endpoint is 3-year disease-free survival (DFS). Secondary endpoints include 5-year DFS, local recurrence rate, systemic recurrence rate, cost-effectiveness, and overall survival. We hypothesized that our experimental group (arm B) will have a 3-year DFS of 75% and a non-inferiority margin of 15%. Discussion Identifying whether patients require PCRT is one of the critical issues in locally advanced rectal cancer. This study aims to elucidate whether PCRT may not be required for all patients with stage II/III rectal cancer, especially for the MRI-based intermediate-risk group (with cT1–2N1 or cT3N0) without CRM involvement and lateral lymph node metastasis. If the findings indicate that our proposed treatment, which omits PCRT, is non-inferior to the standard treatment, then patients may avoid unnecessary radiation-related toxicity, have a shorter treatment duration, and save on medical costs. Trial registration ClinicalTrials.gov, NCT02167321. Registered on 19 June 2014.

Summary: Background/objective: Although many studies have demonstrated similar perioperative outcomes for single-incision laparoscopic surgery (SILS) and conventional laparoscopic surgery (CLS) for colon cancer, few have directly compared the costs of them. We aimed to compare costs between SILS and CLS for colon cancer. Methods: We analyzed the clinical outcomes and overall hospital costs of patients who underwent laparoscopic surgery for colon cancer from July 2009 to September 2014 at our institution; 288 were used for analysis after propensity score matching. The total hospital charge, including fees for the operation, anesthesia, preoperative diagnosis, and postoperative management was analyzed. Results: The total hospital charges were similar in both groups ($8770.40 vs. $8352.80, P = 0.099). However, the patients' total hospital bill was higher in the SILS group than in the CLS group ($4184.82 vs. $3735.00, P

BACKGROUND Comparable to circumferential resection margin in rectal cancer, radial margin is a potential prognostic factor in colon cancer that has just begun to be studied. No previous studies have investigated the influence of radial margin in the context of complete mesocolic excision. OBJECTIVE This study aimed to examine the impact of radial margin on oncologic outcomes after complete mesocolic excision for colon cancer. DESIGN We retrospectively reviewed patients with stage I to III colon cancer who underwent curative resection from October 2010 to March 2013. SETTINGS This study was conducted using the prospective colorectal cancer registry of Severance hospital. PATIENTS A total of 834 consecutive patients who underwent complete mesocolic excision for colon adenocarcinoma were included. INTERVENTIONS We assigned patients into 3 groups according to radial margin distance: group A, radial margin ≥2.0 mm; group B, 1.0 ≤ radial margin < 2.0 mm; group C, radial margin

Serum carcinoembryonic antigen (CEA) is a widely used tumor marker in colorectal cancer (CRC), but within normal range of preoperative CEA levels the clinical significance of CEA is unknown. The aim of this study was to evaluate the usefulness of CEA within the normal range as a prognosticator of non-metastatic CRC. This retrospective cohort study included 2021 CRC patients with normal preoperative CEA who underwent elective curative surgery (discovery group). We determined the optimal cut-off value for disease-free survival (DFS) discrimination using the Contal and O’Quigley method. We also assessed the prognostic significance of the cut-off value in a prospective cohort of 171 stage III colon cancer patients treated with oxaliplatin-based adjuvant chemotherapy (validation group). The optimal cut-off CEA value was 2.1 ng/mL in the discovery group. The DFS rates were significantly poorer in patients with high-normal preoperative CEA levels (2.1–5.0 ng/mL) than in those with low-normal CEA levels (

Although studies of robotic rectal cancer surgery have demonstrated the effects of learning on operation time, comparisons have failed to demonstrate differences in clinicopathological outcomes between unadjusted learning phases. This study aimed to investigate the learning curve of robotic rectal cancer surgery for clinicopathological outcomes and compare surgical outcomes between adjusted learning phases. Study design We enrolled 506 consecutive patients with rectal adenocarcinoma who underwent robotic resection by a single surgeon between 2007 and 2018. Risk-adjusted cumulative sum (RA-CUSUM) for surgical failure was used to analyze the learning curve. Surgical failure was defined as the occurrence of any of the following: conversion to open surgery, severe complications (Clavien–Dindo grade ≥ 3a), insufficient number of harvested lymph nodes (LNs), or R1 resection. Comparisons between learning phases analyzed by RA-CUSUM were performed before and after propensity score matching. In RA-CUSUM analysis, the learning curve was divided into two learning phases: phase 1 (1st–177th cases, n = 177) and phase 2 (178th–506th cases, n = 329). Before matching, patients in phase 2 had deeper tumor invasion and higher rates of positive LNs on pretreatment images and preoperative chemoradiotherapy. After matching, phase 1 (n = 150) and phase 2 (n = 150) patients exhibited similar clinical characteristics. Phase 2 patients had lower rates of surgical failure overall and these components: conversion to open surgery, severe complications, and insufficient harvested LNs. For robotic rectal cancer surgery, surgical outcomes improved after the 177th case. Further studies by other robotic surgeons are required to validate our results.

Background: Developing personalized strategies for cancer has shown good efficacies. Methods: We assessed the molecular targets programmed death ligand 1 (PD-L1), microsatellite instability (MSI), and PIK3CA. Seventy-four patients with liposarcomas who underwent curative resection were assessed for PD-L1 expression in the tumor and tumor-infiltrating lymphocytes (TILs), mismatch repair proteins (MLH1, PMS2, MSH2, and MSH6) by immunohistochemistry, MSI using polymerase chain reaction, and PIK3CA mutation/amplification using pyrosequencing and fluorescence in situ hybridization. Results: Seventeen (23%) cases were TIL+ (≥1 + expression) and associated with longer 5-year overall survival than those with TIL– tumors (84.4 vs. 60.8%, p = 0.007). Six (35.3%) PD-L1+ tumors were detected only in TIL+ cases, with none detected in tumor cells. Two well-differentiated liposarcomas showed MSI, one low and one high with concurrent loss of MLH1, MSH6, and PMS2. PIK3CA mutation was detected in 7 (9.5%) [exon 9 (n = 4) and exon 20 (n = 3)] and only 1 Q546K mutation was a PD-L1+ tumor. PIK3CA copy number gain was detected in 18 (24.4%) and was associated with TIL+ tumors (p = 0.045). Conclusions: Our comprehensive immuno-molecular panel suggests that liposarcoma should be categorized based on the molecular genomic subtype for precision medicine.

Objective The aim of this study is to develop a nomogram for prediction of pathologic complete remission (pCR) after preoperative chemoradiotherapy (CRT) for rectal cancer. Methods mRNA expression levels of seven molecular markers [p53, p21, Ki-67, vascular endothelial growth factor (VEGF), CD133, CD24, CD44] were measured by reverse transcriptase polymerase chain reaction (RT-PCR) in 120 rectal cancers. Endoscopic findings of clinical complete remission (cCR) and biologic variables were used to construct nomogram in the training group (n=80), which was validated in the validation group (n=40). Results mRNA expression levels of four markers (p53, p21, Ki67, CD133) correlated with pCR (24/80, 30.0%) in the training group. Low expression of p53 and/or high expression of p21, Ki67 and CD133 showed greater pCR rate. pCR was shown in 18 (69.2%) of 26 cases showing endoscopic cCR in the training group. Higher pCR rate was demonstrated in lower tumor location than middle tumor (19/49, 38.8% vs. 5/31, 16.1%). A nomogram for prediction of pCR was developed from the multivariate prediction model using these six variables, which showed good discrimination ability in the training group [area under the curve (AUC)=0.945] and validation group (AUC=0.922). The calibration plot showed good agreement between actual and predicted pCR in both patient groups. Conclusions Nomogram for assessment of pCR can be useful for making treatment decisions after CRT according to predicted responses.

Purpose Upfront systemic chemotherapy with target agents has been recommended for patients with stage IV colon cancer. Some with partial response are considered for curative resection. There is high risk of developing postoperative complications following upfront systemic chemotherapy. We aimed to evaluate short-term perioperative outcomes of curative surgery after upfront chemotherapy in comparison with upfront surgery in patients with metastatic colon cancer. Methods Between January 2010 and October 2015, 146 patients (80 in the surgery first group, 66 in the upfront chemotherapy group) who underwent surgical resection before or after systemic chemotherapy for metastatic colon cancer were included in the present study. All decisions for treatment were made through a multidisciplinary team. Postoperative clinical outcomes and complications were analyzed to compare the groups. Results There was no difference between the 2 groups in terms of postoperative clinical outcomes. Overall complication rates were not different between the groups (surgery first group: 46.3% vs. upfront chemotherapy group: 60.6%; P = 0.084). When classified according to the Clavien-Dindo method, there was no difference between the 2 groups in terms of major complications (grade 3 or more) (surgery first group: 18.9% vs. upfront chemotherapy group: 27.5%; P = 0.374). Conclusion There was no significant increase in major postoperative complications in metastatic colon cancer patients who received upfront chemotherapy followed by curative surgery. Careful patient selection and treatment planning are important.

Purpose Tailgut cysts are rare congenital or developmental lesions that arise from vestiges of the embryological hindgut. They are usually present in the presacral space. We report our single-center experience with managing tailgut cysts. Methods We conducted a retrospective analysis of 24 patients with tailgut cyst treated surgically at the Colorectal Surgery Department of Severance Hospital, Yonsei University, Seoul, South Korea, between 2007–2018. Results This study included 24 patients (18 females) with a median age of 51.5 years (range, 21–68 years). Ten cases were symptomatic and 14 were asymptomatic. Cysts were retrorectal in 21 patients. Cysts were below the coccyx level in 16 patients, opposite the coccyx in 6, and above the coccyx in 2. Cysts were supralevator in 5 patients, had a supra- and infralevator extension in 18 patients, and were infralevator in 1. Ten patients were managed using an anterior laparoscopic approach, 11 using a posterior approach, and 3 using a combined approach. Mean cyst size was 5.5 ± 2.7 cm. Postoperative complications were Clavien-Dindo (CD) classification grade II in 9 patients (37.5%) and CD grade III in 1 (4.2%). The posterior approach group showed the highest rate of complications (P = 0.021). Patients managed using a combined approach showed a larger cyst size (P < 0.001), longer operation times (P < 0.001), and a greater likelihood of tumor level above the coccyx (P = 0.002) compared to other approaches. The tumors of 2 male patients were malignant: 1 was a neuroendocrine tumor treated with radiotherapy, while the other was a closely followed adenocarcinoma. Median follow-up was 12 months (range, 1–66 months) with no recurrence. Conclusion Tailgut cysts are uncommon but can cause perineal or pelvic pain. Complete surgical excision via an appropriate approach according to tumor size, location, and correlation with adjacent pelvic floor muscles is the key treatment.

Total mesorectal excision (TME) is challenging to perform in a deep, narrow pelvis. While previous studies used pelvimetry to assess bony pelvic structures, there is no consensus on exact definition of deep, narrow pelvis. We hypothesized that the shape of pelvic floor muscle may impact the performance of transabdominal pelvic dissection. We aimed to evaluate which parameters of the shape of pelvic floor muscle impact the difficulty of TME and present a predictive reference value for TME difficulty. From January 2015 to December 2015, 85 consecutive patients who had undergone curative resection for middle to lower rectal cancer were retrospectively studied. Pelvimetry was performed using preoperative T2-weighted magnetic resonance imaging. Predictive factor analysis for surgical duration was studied using linear regression. Mann–Whitney U test, comparing surgical duration between two groups classified by predictive factor, was used for the analysis of reference value. Multivariate analysis revealed that body mass index, protective stoma, number of surgeon, and incline angle of pelvic floor muscle (β) were independent predictors of surgical duration. Test statistics of Mann–Whitney U for the difference in surgical duration between groups above and below a β of 54° were maximized. The incline angle of pelvic floor muscle is an independent predictor of surgical duration. In patients with steeper incline of PFM, transabdominal TME is expected to be difficult. This index is novel, but needs to be further validated.

With increasing rates of sphincter preservation because of advances in preoperative chemoradiation, restoration of bowel continuity has become a main goal of rectal cancer treatment. However, in many patients, postoperative bowel dysfunction negatively affects the quality of life.This study aimed to analyze predictors of bowel dysfunction after sphincter-preserving surgery in patients with rectal cancer.This was a cross-sectional study.Assessment of bowel dysfunction was conducted between November 2015 and June 2017 at our institution.A total of 316 patients with rectal cancer who underwent sphincter-preserving surgery between February 2009 and April 2017 and agreed with an interview for assessing bowel dysfunction were included.Bowel dysfunction was assessed with the Memorial Sloan Kettering Cancer Center Bowel Function Instrument and Wexner score. All the assessments were conducted face-to-face by the same interviewer.The median time interval between the restoration of bowel continuity and assessment was 10 months (interquartile range, 3-37), and the median total Memorial Sloan Kettering Cancer Center and Wexner scores were 65 (interquartile range, 58-73) and 6 (interquartile range, 0-11). The time interval was correlated with the Memorial Sloan Kettering Cancer Center scores (rho, 0.279) and Wexner scores (rho, -0.306). In a multivariate analysis, handsewn anastomosis and short time interval (≤1 year) were independently associated with poor bowel function (Memorial Sloan Kettering Cancer Center score ≤65). A short time interval (≤1 year), preoperative chemoradiation, and ileostomy were independently associated with major fecal incontinence (Wexner ≥8).Selection bias may be inherent.Bowel function recovers with time after the restoration of bowel continuity. A short time interval, handsewn anastomosis, preoperative chemoradiation, and ileostomy were significantly associated with poor bowel function or major fecal incontinence. Surgeons should discuss postoperative bowel dysfunction and its predictive factors with the patients. See Video Abstract at http://links.lww.com/DCR/A930.

BACKGROUND A survival paradox of stage IIB/IIC and IIIA colon cancer has been consistently observed throughout revisions of the TNM system. This study aimed to understand this paradox with clinicopathological and molecular differences. METHODS Clinicopathological characteristics of patients with pathologically confirmed stage IIB/IIC or IIIA colon cancer were retrospectively reviewed from a database. Publicly available molecular data were retrieved, and intrinsic subtypes were identified and subjected to gene sets enrichment analysis (GSEA). RESULTS Among the 159 patients included in the clinicopathological analysis, those at stage IIB/IIC had worse 3-year disease-free and overall survival than those at stage IIIA (59.3% vs 91.7%, P

Although self-expandable metal stents (SEMS) are widely used as a bridge to surgery (BTS) in patients with malignant colorectal cancer obstruction, there has been some debate about their effect on long-term oncological outcomes. Furthermore, data on the safety and feasibility of minimally invasive surgery (MIS) combined with stent placement are scarce. We aimed to determine the long-term oncological outcomes of SEMS as a BTS, and the short-term outcomes of SEMS used with minimally invasive colorectal surgery. Data from patients who were admitted with malignant obstructing colon cancer between January 2006 and December 2015 were retrospectively reviewed; 71 patients underwent direct surgery and 182 patients underwent SEMS placement as a BTS. Long-term and short-term outcomes of the groups were compared. In a subgroup analysis of the BTS group, the short-term outcomes of conventional open surgery and MIS were compared. There were no differences in long-term oncologic outcomes between groups. The primary anastomosis rate was higher in the stent group than in the direct surgery group. In the stent group, postoperative complication rates were lower in the minimally invasive group than in the open surgery group. Time to flatus and time to soft diet resumption were shorter in the minimally invasive group, as was length of hospital stay. Elective surgery after stent insertion does not adversely affect long-term oncologic outcomes. Furthermore, MIS combined with stent insertion for malignant colonic obstruction is safe and feasible.

Background The National Lung Screening Trial (NLST) and NELSON trial showed that low-dose chest computed tomography (LDCT) screening significantly reduced the mortality form lung cancer. Although cancer survivors are known to have high risk for second malignant neoplasm (SMN), the usefulness of LDCT screening for lung cancer in cancer survivors is not clear. Methods Between August 2016 and August 2017, 633 long-term colorectal cancer (CRC) survivors visited the survivorship clinic in Cancer Prevention Center, Yonsei Cancer Center, Seoul, Republic of Korea. We surveyed the smoking status and recommended LDCT screening to ever-smoking CRC survivors aged 55–80 years. The participants were classified into three risk groups: risk group 1 (RG1) who met the NLST criteria (Age 55–74 years, ≥ 30 pack-years of smoking, smoking cessation < 15 years); risk group 2 (RG2) who would not meet the NLST criteria but were at increased 6-year risk of lung cancer (PLCOM2012 ≥ 0.0151); risk group 3 (RG3) who did not meet any of the criteria above. Results Among 176 ever-smoking CRC survivors, 173 (98.3%) were male, 32 (18.2%) were current-smoker, and median age was 66 years (range, 55–79 years). We found 38 positive findings (non-calcified nodule ≥ 4 mm), 8 clinically significant findings, 66 minor abnormalities, and 64 negative findings on LDCT. Positive findings were identified in 15 of 79 (19.0%) of RG1, in 9 of 36 (25%) of RG2, and in 14 of 61 (23.0%) of RG3. Second primary lung cancers were found in 2 patients of RG2, and in 1 patient of RG3. SMN was most frequently found in RG2 (11 of 36 patients, 30.6%), compared with RG1 (12.7%) or RG3 (9.8%) (P = 0.016). Conclusions LDCT screening for lung cancer in Korean CRC survivors is feasible. Well-designed clinical trial for defining high risk patients for lung cancer among CRC survivors is needed.

BackgroundAlthough the current standard preoperative chemoradiotherapy (PCRT) for stage II/III rectal cancer decreases the risk of local recurrence, it does not improve survival and increases the likelihood of preoperative overtreatment, especially in patients without circumferential resection margin (CRM) involvement.MethodsStage II/III rectal cancer without CRM involvement and lateral lymph node metastasis was radiologically defined by preoperative magnetic resonance imaging (MRI). Patients who received PCRT followed by total mesorectal excision (TME) (PCRT group) and upfront surgery (US) with TME (US group) between 2010 and 2016 were analyzed. We derived cohorts of PCRT group versus US group using propensity-score matching for stage, age, and distance from the anal verge. Three-year relapse-free survival rate, disease-free survival (DFS), and overall survival (OS) were compared between the two groups.ResultsA total of 202 patients were analyzed after propensity score matching. There were no differences in baseline characteristics. The median follow-up duration was 62 months (interquartile range, 46–87). There was no difference in the 3-year disease-free survival rate between the PCRT and US groups (83 vs. 88%, respectively; p=0.326). Likewise, there was no significant difference in the 3-year OS (89 vs. 91%, respectively; p=0.466). The 3-year locoregional recurrence rates (3 vs. 2% with US, p=0.667) and distant metastasis rates (16 vs. 11%, p=0.428) were not significantly different between the two groups. Time to completion of curative treatment was significantly shorter in the US group (132 days) than in the PCRT group (225 days) (pConclusionUsing MRI-guided selection for better risk stratification, US without neoadjuvant therapy can be considered in early stage patients with good prognosis. PCRT may not be required for all stage II/III rectal cancer patients, especially for the MRI-proven intermediate-risk group (cT1-2/N1, cT3N0) without CRM involvement and lateral lymph node metastasis. Further prospective studies are warranted.

Studies find similar perioperative outcomes between single-incision laparoscopic surgery (SILS) and conventional laparoscopic surgery (CLS) for colon cancer. However, few have reported long-term outcomes of SILS versus CLS. We aimed to compare long-term postoperative and oncologic outcomes as well as perioperative outcomes between SILS and CLS for colon cancer. A total of 641 consecutive patients who underwent laparoscopic surgery for colon cancer from July 2009 to September 2014 were eligible for the study. Data from 300 of these patients were used for analysis after propensity score-matching (n = 150 per group). Variables associated with short- and long-term outcomes were analyzed. The SILS group had a shorter mean total incision length, less postoperative pain, and a similar mean rate of incisional hernia (2.7% versus 3.3%) compared with the CLS group. The 7-year overall and disease-free survival rates were 92.7% versus 94% (p = 0.673) and 85.3% versus 84.7% (p = 0.688) in the SILS and CLS groups, respectively. Compared with CLS, SILS for colon cancer appeared to be safe in terms of perioperative and long-term postoperative and oncologic outcomes. The results suggested that SILS is a reasonable treatment option for colon cancer for a selected group of patients.

Background Even though the validity of the carcinoembryonic antigen (CEA) test has been shown for monitoring colorectal cancer recurrence after surgery, it has been applied without specification to the site of recurrence. In the present study, we aimed to verify the validity of CEA as a site-specific surveillance tool in colorectal cancer after curative resection by analyzing the sensitivity of CEA according to the pattern of recurrence. Methods A total of 722 patients diagnosed with recurrent colorectal cancer after curative resections were enrolled, and their medical records were reviewed. Using a cutoff CEA value of 5 ng/ml at the time of detection, the sensitivity of the CEA test according to the pattern of recurrence (locoregional or systemic recurrence) and detailed information about the location of the recurrence sites were investigated. Results In patients with recurrence in the peritoneum, combined sites, and the liver, the sensitivities of CEA test were 59.4%, 51.3%, and 44.8%, respectively. These values were higher than those in the para-aortic lymph nodes, lungs, and the brain, with sensitivities of 30.4%, 23.6%, and 16.7%, respectively. In the subset analysis, the CEA test sensitivities for patients with recurrence in the peritoneum, liver, and para-aortic lymph nodes were 61.9%, 53.2%, and 22.2% in colon cancer and 54.5%, 36.0%, and 35.7% in rectal cancer, respectively. Conclusions Postoperative surveillance CEA levels may have different values according to the site of recurrence. Therefore, a follow-up strategy considering site-specific CEA sensitivity after surgery could improve early detection of recurrent colorectal cancer.

The aim of this study was to analyze clinical outcomes after surgical and/or conservative management of patients with colonic diverticulitis. Between January 2001 and November 2018, data for 1175 patients (right (Rt.) side: n = 1037, left (Lt.) side: n = 138) who underwent conservative management (n = 987) and surgical management (n = 188) for colonic diverticulitis were retrieved from a retrospective database. The Rt. sided was defined up to the proximal two-thirds of the transverse colon and Lt. sided was defined from the distal one-third of the transverse colon. The overall incidence of colonic diverticulitis is gradually increasing. The mean age of all patients was 43.2 ± 17 and was significantly higher in patients with Lt.-sided (57.0 ± 15.7) than with Rt.-sided (41.4 ± 13.4) diverticulitis (p = 0.001). The most common lesion site was cecum (71.7%, n = 843). First-time attacks were the most common (91.0%, n = 1069). The surgical rate was 12.2% on the right. sided and 44.9% on the left sided (p < 0.005). The mean age, age distribution, BMI, open surgery rate, stoma formation rate, and Hinchey types III and IV rate were significantly higher in Lt. sided than in Rt. sided (p < 0.005). Older age, higher BMI (≥ 25), and Hinchey types III and IV were significantly associated with surgical risk factors of diverticulitis (p < 0.005). Base on present study, Lt.-sided colonic diverticulitis tends to be more severe than Rt. sided, and surgery is more often required. In addition, colonic diverticulitis that requires surgery seems to be older and more obese on Lt. sided.

Summary: Background/objective: Some locally advanced rectal cancer (LARC) patients treated with neoadjuvant chemoradiotherapy (CRT) prior to total mesorectal excision (TME) show early recurrence with a short disease-free interval. This is unacceptable for patients and their families, necessitating re-evaluation of the treatment process. We aimed to evaluate the risk factors and prognostic impact of early recurrence in patients who received preoperative CRT (pCRT) followed by TME for LARC. Methods: Of 714 patients who underwent curative resection after pCRT for LARC from January 2010 to December 2016, we included 139 who developed recurrence after resection. Patients were divided into an early recurrence group, diagnosed

Although multiple studies have examined anastomotic leakage (AL) after low anterior resection (LAR), their definitions of AL varied, and few have studied late diagnosed AL after surgery. This study aimed to characterize late AL after anal sphincter saving surgery (SSS) for rectal cancer by examining clinical characteristics, risk factors, and management of patients with late AL compared with early AL. Data from January 2005 to December 2014 were collected from a total of 1903 consecutive patients who underwent anal sphincter saving surgery for rectal cancer and were retrospectively reviewed. Late AL was defined as AL diagnosed more than 30 days after surgery. Variables and risk factors associated with early and late diagnosed AL were analyzed by multivariate logistic regression. Overall, early, and late rates of AL were 13.7%, 6.7%, and 7%, respectively. Receiving neoadjuvant chemoradiotherapy (nCRT) was a risk factor for developing late AL, but not early AL (OR, 3.032; 95% CI, 1.947–4.722; p

Robotic surgery has advantages in terms of the ergonomic design and expectations of shortening the learning curve, which may reduce the number of patients with adverse outcomes during a surgeon’s learning period. We investigated the differences in the learning curves of robotic surgery and clinical outcomes for rectal cancer among surgeons with differences in their experiences of laparoscopic rectal cancer surgery. Patients who underwent robotic surgery for colorectal cancer were reviewed retrospectively. Patients were divided into five groups by surgeons, and their clinical outcomes were analyzed. The learning curve of each surgeon with different volumes of laparoscopic experience was analyzed using the cumulative sum technique (CUSUM) for operation times, surgical failure (open conversion or anastomosis-related complications), and local failure (positive resection margins or local recurrence within 1 year). A total of 662 patients who underwent robotic low anterior resection (LAR) for rectal cancer were included in the analysis. Number of laparoscopic LAR cases performed by surgeon A, B, C, D, and E prior to their first case of robotic surgery were 403, 40, 15, 5, and 0 cases, respectively. Based on CUSUM for operation time, surgeon A, B, C, D, and E’s learning curve periods were 110, 39, 114, 55, and 23 cases, respectively. There were no significant differences in the surgical and oncological outcomes after robotic LAR among the surgeons. This study demonstrated the limited impact of laparoscopic surgical experience on the learning curve of robotic rectal cancer surgery, which was greater than previously reported curves.

Tumor location and KRAS mutational status have emerged as prognostic factors of colorectal cancer. We aimed to define the prognostic impact of primary tumor location and KRAS mutational status among synchronous colorectal liver metastases (CRLM) patients who underwent simultaneous curative-intent surgery (SCIS). We compared the clinicopathologic characteristics and long-term outcomes of 227 patients who underwent SCIS for synchronous CRLM, according to tumor location and KRAS mutational status. We cross-classified tumor location and KRAS mutational status and compared survival outcomes between the four resulting patient groups. Forty-one patients (18.1%) had right-sided (RS) tumors and 186 (81.9%) had left-sided (LS) tumors. One-third of tumors (78/227) harbored KRAS mutations. The KRAS mutant-type (KRAS-mt) was more commonly observed among RS tumors than among LS tumors [21/41 (51.2%) vs. 57/186 (30.6%), p = 0.012]. Median follow-up time was 43.4 months. Patients with RS tumors had shorter survival times than those with LS tumors [median disease-free survival (DFS): RS, 9.9 months vs. LS, 12.1 months, p = 0.003; median overall survival (OS): RS, 49.7 months vs. LS, 88.8 months, p = 0.039]. RS tumors were a negative prognostic factor for DFS [hazard ratio (HR) 1.878, p = 0.001] and OS (HR 1.660, p = 0.060). RS KRAS-mt and LS KRAS wild-type (KRAS-wt) tumors had the worst and best oncological outcomes, respectively. Tumor location has a prognostic impact in patients who underwent SCIS for CRLM, and RS KRAS-mt tumors yielded the worst oncological outcome. These results may allow for more tailored multimodality treatments.

Purposes Although adjuvant chemotherapy (AC) has been established as a standard of treatment for advanced rectal cancer, there is no guideline regarding the timing of AC initiation. In this study, we aimed to evaluate the oncologic outcome of early AC initiation and clarify the ideal time to AC among rectal cancer patients receiving preoperative chemo-radiotherapy (preCRT). Methods The medical records of 719 patients who underwent curative resection followed by AC for rectal cancer were analyzed retrospectively. Data distributions were compared according to the calculated cut-off for AC initiation, survival results, and chemotherapy-induced toxicity. Additionally, patients were divided into two groups according to preCRT status and compared with respect to differences in the optimal time to AC. Results Overall, a cut-off time point of 20 days after surgery for AC initiation was identified as the optimal interval; this yielded a significant difference in disease-free survival but no significant difference in AC toxicity. In the cut-off analysis of patients treated without preCRT, 19 days was identified as the optimal time to AC. However, for patients treated with preCRT, no significant value affected the survival outcome. Conclusions Earlier initiation of AC (within approximately 3 weeks) was associated with better oncological outcomes among patients with rectal cancer. Additionally, the optimal timing of AC was unclear among patients who received preCRT; this might be attributable to an undetermined role of AC after preCRT or the effects of complications such as anastomotic leakage.