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Introduction: Obstruction in colon cancer is a well-known risk factor for worse oncologic outcomes. However, studies on differences in survival of patients with incomplete obstructive colon cancer (IOCC) by tumor location are insufficient. Thus, the aim of this study was to compare oncologic outcomes between IOCC and non-obstructive colon cancer (NOCC) according to tumor location. Methods: From January 2010 to December 2015, a total of 2,004 patients diagnosed with stage II or stage III colon adenocarcinoma who underwent elective colectomy were included (IOCC, n = 405; NOCC, n = 1,599). Incomplete obstruction was defined as a state in which colonoscopy could not pass through the cancer lesion but did not require emergent surgery, stent insertion, or stoma formation because the patient was asymptomatic without problem in bowel preparation. Kaplan–Meier method and log-rank tests were used to compare survival between IOCC and NOCC. Multivariable analysis was performed to determine which factors affected survivals. Results: Stage III IOCC patients showed significantly lower overall survival (OS) and recurrence-free survival (RFS). Stage II IOCC patients and stage III NOCC patients had similar survival curves. IOCC patients with tumors on the right side showed worse OS than other patients. In multivariable analysis, incomplete obstruction was an independent risk factor for worse OS and RFS in all stages. Tumor located at the right side in stage III was an independent risk factor for RFS (HR: 1.40, p = 0.030). Conclusions: Patients with IOCC showed significantly worse survival outcomes than those with NOCC. Stage II IOCC patients and stage III NOCC patients showed similar survival. Patients with stage III IOCC located at the right side showed significantly worse oncologic outcomes than those located at the left side. These results confirm that prognosis is different depending on the presence of incomplete obstruction and the location of the tumor, even in the same stage. [ABSTRACT FROM AUTHOR]

Aim: There is controversy about the treatment of para‐aortic lymph node (PALN) metastasis and usefulness of surgical removal. We investigated the clinical effects of synchronous isolated PALN dissection in patients with this metastasis. Methods: Patients with colorectal cancer with isolated PALN metastasis were selected between January 2008 and December 2016 at Samsung Medical Center. Patients who were selected for gross‐free PALN dissection were set as the dissection group (DG). Patients who did not undergo PALN dissection or underwent biopsy were set as the non‐dissection group (NDG). The oncological and operative outcomes were compared. Results: A total of 73 patients were recruited. The most clinical and pathological characteristics were not significantly different. The incidence of postoperative complications was also similar. The 5‐year overall survival of DG patients was 33.9%, that of NDG patients was 10.1%, and the survival curves were significantly different (P = 0.044). Multivariate analysis revealed that location of tumour in the left colon rather than in the right colon was a risk factor affecting survival in sub‐analysis. Conclusion: PALN dissection did not increase postoperative complications and had a better effect on patient survival. It is suggested that lymphadenectomy be performed more aggressively when PALN metastasis is seen in patients with right colon cancer. [ABSTRACT FROM AUTHOR]

Background: The aim of the study was to determine factors predicting lymph node metastasis in patients with T1 or T2 colon cancer. Methods: A total of 906 patients with T1 or T2 colon cancer who underwent colon resection with regional lymphadenectomy in a tertiary hospital, from January 2008 to December 2013, were analyzed. The prognostic factors for LN metastasis and the risk factors for survival were analyzed. Results: There were 728 patients (80.4%) without lymph node metastasis (LN-negative group) and 178 patients (19.6%) with lymph node metastasis (LN-positive group). Tumor invasion depth (P < 0.001), lymphatic invasion (P < 0.001), and perineural invasion (P = 0.008) were significantly different between the two groups. During the median follow-up period of 69 months, the 5-year disease-free survival rate was 98.6% for the LN-negative group and 92.8% for the LN-positive group (P ≤ 0.001). In multivariate analysis, influencing factors associated with disease-free survival rate were LN metastasis (P = 0.001) and perineural invasion (P = 0.040). Female, depth of tumor invasion (P = 0.001), and lymphatic invasion (P < 0.001) were significant independent predictive factors for lymph node metastasis in multivariate analysis. Conclusion: Positive LN status predicted poor disease-free survival in patients with early cancer. This suggests that depth of tumor invasion ≥ sm2 and the presence of lymphatic invasion in early colon cancer provide useful information to determine which patients would benefit from radical surgery. [ABSTRACT FROM AUTHOR]

Background: The diagnostic impact of lymphovascular invasion (LVI), perineural invasion (PNI), and tumor budding in stage I colon cancer is currently unknown. This study was conducted to evaluate the prognostic impact of LVI, PNI, and tumor budding in stage I colon cancer. Methods: From January 2008 to December 2013, 720 patients who underwent curative surgery and were diagnosed with stage I colon cancer were reviewed retrospectively. These patients were categorized into two groups based on LVI, PNI, and tumor budding: the no risk group (n = 566) and risk group (n = 154). Results: Median follow-up period was 103.5 months, and the 5-year disease-free survival rate of the risk group was significantly lower than that of the no risk group (p = 0.025). In multivariate analysis, only the risk group had prognostic factors for 5-year disease-free survival (p = 0.036). In addition, only differentiation was an independent predictor in the risk group (p = 0.009). Conclusion: LVI, PNI, and tumor budding are strong prognostic factors for stage I colon cancer. Therefore, patients with positive LVI, PNI, or tumor budding should receive close follow-up and potentially be considered for chemotherapy. [ABSTRACT FROM AUTHOR]

Purpose: The goal of this study was to evaluate the long-term oncologic outcomes after laparoscopic converted surgery for patients with colon cancer. Methods: Retrospective database of consecutive curative-intent laparoscopic-assisted surgery for primary stage I–III colon cancer was reviewed from 2000 to 2013. The patients were divided into non-conversion and conversion groups. The patient characters, operative features, perioperative parameters, pathologic features, and oncologic outcomes were compared. Results: A total of 4010 patients were included in the study: 3929 in the non-conversion group and 81 (2%) in the conversion group. The median follow-up period was 63.9 months. There were significant differences in age, preoperative clinical T-stage, and tumor size between the groups. In operative details between the two groups, there were also significant differences in access to surgery, tumor location, cancer obstruction, cancer perforation, and estimated blood loss (P < 0.001). The two most common reasons for conversion were adhesion (n = 37, 46%) and bleeding (n = 21, 26%). Multivariate analysis showed that conversion was an independent predictor of both overall survival (OS) (P < 0.001) and disease-free survival (P = 0.003). The 5-year OS rate of the conversion group was 79.6%, and that of the non-conversion group was 96.2% (P < 0.001). The multivariate predictors of conversion were age, type of surgery, cancer obstruction, cancer perforation, and clinical T-stage. Conclusion: Conversion to open surgery may affect patient survival and recurrence after laparoscopic-assisted surgery for colon cancer. Our data suggest that conversion is associated with poor outcomes, but we should not hesitate to convert it to patients who have difficulty in laparoscopic surgery. [ABSTRACT FROM AUTHOR]

Background: The introduction of complete mesocolic excision (CME) with central vessel ligation (CVL) for right-sided colon cancer has improved oncologic outcomes. However, there is controversy over the oncologic safety of laparoscopic CME with CVL. This study compared short-term and long-term oncologic outcomes between laparoscopic and open modified CME (mCME) with CVL in patients with right-sided colon cancer.Methods: We enrolled 1239 patients who underwent open mCME with CVL and 1010 patients treated by a laparoscopic approach for right-side colon cancer between 2000 and 2013 and used 1:1 propensity score matching to adjust for potential baseline confounders between two groups.Results: After propensity score matching, 683 patients who underwent open mCME with CVL were compared with 683 patients treated with a laparoscopic approach. There were no significant differences between these groups in age, sex, ASA score, TNM stage, tumor size, lymphovascular invasion, and perineural invasion. Comparison of open and laparoscopic mCME groups showed no significant difference in postoperative morbidity (21.4 vs. 18.3%, p = 0.175) and mortality (0.1 vs. 0%, p = 1.000). The laparoscopic mCME group showed shorter length of hospital stay. The 5-year overall survival rate was 83.7% in the open group and 94.7% in the laparoscopic group (p < 0.001). The laparoscopic group also showed a significantly better 5-year disease-free survival rate (82.7 vs. 88.7%, p = 0.009) and 5-year disease-specific survival rate (83.7 vs. 94.7%, p < 0.001).Conclusion: Laparoscopic modified mesocolic excision with central vascular ligation is a safe and feasible approach with better short-term recovery profiles and potential oncologic benefits than the open approach for right-sided colon cancer. [ABSTRACT FROM AUTHOR]

Background Perineural invasion ( PNI) may influence the prognosis of colon cancer, but little is known about its predictive value. The aim of this study was to reveal the role of PNI in predicting prognosis after curative resection of colon cancer, especially T3N0. Methods Two hundred and fifty-five patients who underwent curative resection for colon cancer at Samsung Medical Center and were later diagnosed with stage T3N0 by a pathological report between November 2004 and December 2007 were retrospectively recruited into the study. Results Among the 255 patients, 156 were male and 99 were female. The mean age was 61 years (range, 25 to 88 years). The most common tumour location was the sigmoid colon (93 patients, 36.5%). The median follow-up period was 61 months (range, 1 to 98 months). PNI was detected in 18 patients (7.1%). Adjuvant chemotherapy was performed in 205 patients (80.4%). The 5-year disease-free survival rate was greater for patients with PNI negative tumours compared with those with PNI positive tumours (92.0% versus 76.0%, P = 0.025). Adjuvant chemotherapy was not associated with significant differences in survival rate (94.8% versus 96.9%, P = 0.625). On multivariate analysis, PNI was an independent prognostic factor for disease-free and overall survival ( P = 0.046, hazard ratio (HR) = 3.113, 95% confidence interval ( CI) = 1.020-9.505 and P = 0.019, HR = 9.395, 95% CI = 1.453-60.755 respectively). Conclusions PNI is the only significant prognostic factor affecting disease-free and overall survival in patients with T3N0 colon cancer. [ABSTRACT FROM AUTHOR]

Background Although a single incision laparoscopic ( SIL) technique has been used increasingly in colorectal surgery, there are only a few reports on the clinical availability of this approach coupled with low anterior resection ( SIL- LAR) for colorectal cancers. We report here 96 consecutive cases of SIL- LAR and reduced port LAR cases, of which the initial approach was SIL. Methods This is a retrospective review of prospectively collected data of SIL- LAR cases performed by a single surgeon in Samsung Medical Center between June 2011 and June 2012. Results Out of 96 cases, 28 were finished as 'pure' SIL- LAR. Sixty-four cases were performed with one additional port, and four needed two more ports. There was no open conversion. The median duration of operation was 165 min. Proximal and distal resection margins were negative in all cases. Circumferential resection margins were positive in four cases. The median duration of postoperative stay was 7 days and the complication rate was 20%. There were six cases of anastomosis leakage (6%). Conclusion The SIL- LAR technique can be applied safely with the optional use of an additional port. One additional port in the right suprapubic area is useful for obtaining a secure distal division and a safe total mesorectal excision, especially in patients with lower lesions or history of neoadjuvant chemoradiation. [ABSTRACT FROM AUTHOR]

Background and Aim Considering the significant racial and ethnic diversity in genetic variation, it is unclear whether the genome-wide association studies-identified colorectal cancer ( CRC)-susceptibility single-nucleotide polymorphisms ( SNPs) discovered in European populations are also relevant to the Korean population. However, studies on CRC-susceptibility SNPs in Koreans are limited. Methods To investigate the racial and ethnic diversity of CRC-susceptibility genetic variants, we genotyped for the established European CRC-susceptibility SNPs in 198 CRC cases and 329 controls in Korea. To identify novel genetic variants using genome-wide screening in Korea, Illumina Human Hap 370K/610K Bead Chips were performed on 105 CRC patients, and candidate CRC-susceptibility SNPs were selected. Subsequently, genotyping for replication was done in 189 CRC cases and 190 controls. Results Among the European CRC-susceptibility SNPs, rs4939827 in SMAD7 was associated with a significant decreased risk of Korean CRC (age-/gender-adjusted odds ratio [95% confidence interval]: additive model, 0.67 [95% CI, 0.47-0.95]; dominant model, 0.59 [95% CI, 0.39-0.91]). rs4779584 and rs10795668 were associated with CRC risk in females and males, respectively. Among candidate CRC-susceptibility SNPs selected from genome-wide screening, novel SNP, rs17051076, was found to be associated with a significantly increased risk of microsatellite instability-high CRC (age-/gender-adjusted odds ratio [95% confidence interval]: additive model, 4.25 [95% CI, 1.51-11.98]; dominant model, 3.52 [95% CI, 1.13-10.94]) in the replication study. Conclusions rs4939827, rs4779584, and rs10795668 may contribute to the risk of CRC in the Korean population as well as in European populations. Novel rs17051076 could be associated with microsatellite instability-high CRC in Koreans. These associations support the ethnic diversity of CRC-susceptibility SNPs and should be taken into account in large-scale studies. [ABSTRACT FROM AUTHOR]

Abstract: Background: For patients with T3N0M0 colon cancer without known risk factors, the necessity of chemotherapy has no definite consensus. Methods: From 1994 to 2004, we retrospectively analyzed 247 patients who had pathologically confirmed T3N0M0 colon cancer without risk factors. Results: Among the 247 patients, 198 (80.2%) received chemotherapy and 49 (19.8%) underwent surgery alone. The 5-year survival rate was 92.8% for patients with T3N0M0 colon cancer without risk factors. Only chemotherapy increased survival (P = .032) by multivariate analysis. The 5-year survival rates were 85.4% in the surgery-only group and 94.2% in the group that received surgery with chemotherapy. There was no difference in the therapeutic efficacy of 5-fluorouracil, capecitabine, and uracil/tegafur (P = .424) for survival. Conclusion: The results of this study showed that chemotherapy improved the survival of patients with T3N0M0 colon cancer without risk factors. [Copyright &y& Elsevier]

The name of the author of the original published version of this article was presented incorrectly. The author name "JungWook Huh" should have been presented as "Jung Wook Huh". [ABSTRACT FROM AUTHOR]

Abstract Tumor associated glycoprotein 72 (TAG-72) is a membrane-bound glycoprotein complex that is overexpressed in many adenocarcinomas. Recently, monoclonal antibody targeting TAG72, minretumomab, have been introduced as a potential therapeutic target in colorectal cancers (CRC) as well as breast and lung cancers. However, the detailed expression profile of TAG72 and its prognostic effect in CRC are not clear yet. We investigated the relationship between tumor associated glycoprotein 72 (TAG-72) expression and clinicopathologic characteristics in CRC using 3E8 antibody, a fully humanized antibody with the highest affinity to TAG-72. Immunohistochemical staining for TAG-72 was performed in 578 CRC patients, and the results were analyzed using a modified Remmele scoring system (score: 0–12). Of the 578 patients, 144 (24.9%) composed the TAG-72 overexpression (TAG-72high) group. TAG-72high was significantly associated with microsatellite stable tumor (P =.002), lymphatic invasion (P =.001), venous invasion (P =.005), and high pN status (P <.001). In survival analyses, TAG-72high group showed shorter disease-free survival in univariate analysis (P =.001), and TAG-72high was found to be an independent prognostic factor in multivariate analysis (P =.028), in addition to TNM stage. In conclusion, TAG-72 is thought to be the factors involved in the progression of CRC and may be considered as one of the potential therapeutic target. [ABSTRACT FROM AUTHOR]