Evaluation of the advantage of surgeons certified by the endoscopic surgical skill qualification system participating in laparoscopic low anterior rectal resection.

Background: A technical qualification system was developed in 2004 by the Japan Society for Endoscopic Surgery. An analysis of the EnSSURE study on 3188 stage II-III rectal cancer patients, which was performed by including the participation of qualified surgeons as assistants and advisers without restricting their participation as operators, revealed that the participation of technically qualified surgeons in surgery improved the technical and oncological safety of laparoscopic rectal resection. Aim: This secondary retrospective analysis of the EnSSURE study examined the advantage of qualified surgeons participating in laparoscopic low anterior resection (LAR). Methods: The outcomes of low anterior resection were compared between groups with and without the participation of surgeons qualified by the Endoscopic Surgical Skill Qualification System (Q and non-Q groups, respectively). We used propensity score matching to generate paired cohorts at a one-to-one ratio. The postoperative complication rate, short-term results (hemorrhage volume, operative time, number of dissected lymph nodes, open conversion rate, intraoperative complication rate, and R0 resection rate), and long-term results (disease-free survival rate, local recurrence rate, and overall survival rate) were evaluated. Results: The frequencies of postoperative complications, anastomotic bleeding, and intraperitoneal abscess were significantly lower, the operative time was significantly shorter, the postoperative hospital stay was significantly shorter, and the number of dissected lymph nodes was higher in the Q group. No significant differences were observed in disease-free survival, local recurrence, or overall survival rate rates between the groups. Conclusion: The participation of qualified surgeons in LAR is technically advantageous.

Investigation of the impact of COVID-19 on postoperative outcomes using a nationwide Japanese database of patients undergoing laparoscopic distal gastrectomy and low anterior resection for gastric cancer and rectal cancer.

Background: The COVID-19 outbreak made conventional medical care impossible, forcing changes in both healthcare providers and patients. In Japan, COVID-19 infection began spreading in earnest in 2020 and exploded in 2021. There was concern that the medical impact of COVID-19 in 2021 would differ from that in 2020. We aimed to clarify the impact of COVID-19 on mortality and anastomotic leakage in laparoscopic surgery for gastric cancer and rectal cancer in Japan using the National Clinical Database (NCD). Methods: We collected data from patients who underwent laparoscopic distal gastrectomy (LDG) and laparoscopic low anterior resection (LLAR) from January 2018 to December 2021 from the NCD, a web-based surgical registration system in Japan. The number of surgical cases, monthly incidence of mortality and morbidity (anastomotic leakage), standardized mortality ratio (SMR), and standardized morbidity-leakage ratio (SMLR [ratio of observed patients to expected patients calculated using the risk calculator established in the NCD]) were evaluated. Results: The numbers of LDG and LLAR cases continued to decline in the first year of the pandemic in 2020 and were as low in 2021 as in 2020. Although the numbers of robot-assisted LDG and LLAR cases increased, the growth rate was lower than the rate of increase prior to the pandemic. Mortality and anastomotic leakage, two of the most important complications, as assessed by SMR and SMLR, did not worsen during the pandemic in comparison to the pre-pandemic period. Conclusions: Laparoscopic surgeries were performed safely in Japan and were not affected by the COVID-19 pandemic.

Risk factors of bleeding during rectal cancer surgery in obese patients in Japan.

BACKGROUND: According to several clinical trials for patients with rectal cancer, laparoscopic surgery significantly reduces intraoperative complications and bleeding compared with laparotomy and demonstrated comparable long-term results. However, obesity is considered one of the risk factors for increased surgical difficulty, including complication rate, prolonged operation time, and bleeding. METHODS: Patients with clinical pathological stage II/III rectal cancer and a body mass index of ≥25 kg/m2 who underwent laparotomy or laparoscopic surgery between January 2009 and December 2013 at 51 institutions participating in the Japan Society of Laparoscopic Colorectal Surgery were included. These patients were divided into major bleeding (>500 mL) group and minor bleeding (≤500 mL) group. The risk factors of major bleeding were evaluated by univariate and multivariate analyses. RESULTS: This study included 517 patients, of which 74 (19.9%) experienced major bleeding. Patient characteristics did not significantly differ between the two groups. The major bleeding group had a longer operative time (p < 0.001) and a larger tumor size than the minor bleeding group (p = 0.011). In the univariate analysis, age >65 years, laparotomy, operative time >300 min, and multivisceral resection were significantly associated with intraoperative massive bleeding. In the multivariate analysis, age >65 years (odds ratio [OR], 2.29; 95% confidence interval [CI], 1.13-4.82), laparotomy (OR, 20.82; 95% CI, 11.56-39.75), operative time >300 min (OR, 5.39; 95% CI, 1.67-132), and multivisceral resection (OR, 10.72; 95% CI, 2.47-64.0) showed to be risk factors for massive bleeding. CONCLUSION: Age >65 years, laparotomy, operative time >300 min, and multivisceral resection were risk factors for massive bleeding during rectal cancer surgery in patients with obesity.

Impact of the endoscopic surgical skill qualification system on conversion to laparotomy after low anterior resection for rectal cancer in Japan (a secondary analysis of the EnSSURE study).

BACKGROUND AND AIMS: Conversion to laparotomy is among the serious intraoperative complications and carries an increased risk of postoperative complications. In this cohort study, we investigated whether or not the Endoscopic Surgical Skill Qualification System (ESSQS) affects the conversion rate among patients undergoing laparoscopic surgery for rectal cancer. METHODS: We performed a retrospective secondary analysis of data collected from patients undergoing laparoscopic surgery for cStage II and III rectal cancer from 2014 to 2016 across 56 institutions affiliated with the Japan Society of Laparoscopic Colorectal Surgery. Data from the original EnSSURE study were analyzed to investigate risk factors for conversion to laparotomy by performing univariate and multivariate analyses based on the reason for conversion. RESULTS: Data were collected for 3,168 cases, including 65 (2.1%) involving conversion to laparotomy. Indicated conversion accounted for 27 cases (0.9%), while technical conversion accounted for 35 cases (1.1%). The multivariate analysis identified the following independent risk factors for indicated conversion to laparotomy: tumor diameter [mm] (odds ratio [OR] 1.01, 95% confidence interval [CI] 1.01-1.05, p = 0.0002), combined resection of adjacent organs [+/-] (OR 7.92, 95% CI 3.14-19.97, p < 0.0001), and surgical participation of an ESSQS-certified physician [-/+] (OR 4.46, 95% CI 2.01-9.90, p = 0.0002). The multivariate analysis identified the following risk factors for technical conversion to laparotomy: registered case number of institution (OR 0.99, 95% CI 0.99-1.00, p = 0.0029), institution type [non-university/university hospital] (OR 3.52, 95% CI 1.54-8.04, p = 0.0028), combined resection of adjacent organs [+/-] (OR 5.96, 95% CI 2.15-16.53, p = 0.0006), and surgical participation of an ESSQS-certified physician [-/+] (OR 6.26, 95% CI 3.01-13.05, p < 0.0001). CONCLUSIONS: Participation of ESSQS-certified physicians may reduce the risk of both indicated and technical conversion. Referral to specialized institutions, such as high-volume centers and university hospitals, especially for patients exhibiting relevant background risk factors, may reduce the risk of conversion to laparotomy and lead to better outcomes for patients. TRIAL REGISTRATION: This study was registered with the Japanese Clinical Trials Registry as UMIN000040645.

Risk factors for anastomotic leakage after low anterior resection for obese patients with rectal cancer.

PURPOSE: We aimed to analyze the risk factors for anastomotic leakage (AL) after low anterior resection (LAR) in obese patients (body mass index [BMI] ≥ 25 kg/m2) with rectal cancer. METHODS: Data were collected from four hundred two obese patients who underwent LAR for rectal cancer in 51 institutions. RESULTS: Forty-six (11.4%) patients had clinical AL. The median BMI (27 kg/m2) did not differ between the AL and non-AL groups. In the AL group, comorbid respiratory disease was more common (p = 0.025), and the median tumor size was larger (p = 0.002). The incidence of AL was 11.5% in the open surgery subgroup and 11.4% in the laparoscopic surgery subgroup. Among the patients who underwent open surgery, the AL group showed a male predominance (p = 0.04) in the univariate analysis, but it was not statistically significant in the multivariate analysis. Among the patients who underwent laparoscopic surgery, the AL group included a higher proportion of patients with comorbid respiratory disease (p = 0.003) and larger tumors (p = 0.007). CONCLUSION: Comorbid respiratory disease and tumor size were risk factors for AL in obese patients with rectal cancer. Careful perioperative respiratory management and appropriate selection of surgical procedures are required for obese rectal cancer patients with respiratory diseases.

Overexpression of VSNL1 Enhances Cell Proliferation in Colorectal Carcinogenesis.

INTRODUCTION: We have previously reported that overexpression of visinin-like protein 1 (VSNL1) is frequently observed in advanced colorectal adenocarcinomas and correlates with poorer prognosis. In this study, we determined the levels of VSNL1 expression in the earlier stages of colorectal tumors including adenomas and adenocarcinomas, and attempted to clarify the functional significance of VSNL1 overexpression in colorectal carcinogenesis. METHODS: Levels of VSNL expression in colorectal tumor tissues were analyzed using immunohistochemistry. The effects of VSNL1 downregulation and overexpression on cell proliferation, resistance to apoptosis, and invasiveness were determined using two VSNL1-overexpressing colorectal cancer cell lines, CW-2 and HCT-116 and VSNL1 inducibly expressing SNU-C5, respectively. Gene expression signatures in VSNL1-downregulated CW-2 and HCT-116 were identified using transcriptome and gene set enrichment analyses. RESULTS: VSNL1 expression was restricted to only a few crypt cells in the non-tumorous epithelium, whereas it became enhanced in adenomas and adenocarcinomas with the progression of tumorigenesis. Downregulation of VSNL1 in CW-2 and HCT-116 cells suppressed their proliferation through induction of apoptosis. Conversely, overexpression of VSNL1 in SNU-C5 cells enhanced resistance to anoikis. Transcriptome and gene set enrichment analyses revealed that downregulation of VSNL1 altered the expression level of the apoptosis-related gene set in CW-2 and HCT-116 cells. CONCLUSION: VSNL1 plays a role in both the development and progression of colorectal tumors by enhancing cell viability.

Impact of laparoscopic surgery on short-term and long-term outcomes in elderly obese patients with colon cancer.

Background: Laparoscopic surgery is reported to be useful in obese or elderly patients with colon cancer, who are at increased risk of postoperative complications because of comorbidities and physical decline. However, its usefulness is less clear in patients who are both elderly and obese and may be at high risk of complications. Methods: Data for obese patients (body mass index ≥25) who underwent laparoscopic or open surgery for stage II or III colon cancer between January 2009 and December 2013 were collected by the Japan Society of Laparoscopic Colorectal Surgery. Surgical outcomes, postoperative complications, and relapse-free survival (RFS) were compared between patients who underwent open surgery and those who underwent laparoscopic surgery according to whether they were elderly (≥70 y) or nonelderly (<70 y). Results: Data of 1549 patients (elderly, n = 598; nonelderly, n = 951) satisfied the selection criteria for analysis. Length of stay was shorter and surgical wound infection was less common in elderly obese patients who underwent laparoscopic surgery than in those underwent open surgery. There were no significant between-group differences in overall complications, anastomotic leakage, ileus/small bowel obstruction, or RFS. There were also no significant differences in RFS after laparoscopic surgery according to patient age. Conclusion: Laparoscopic surgery is safe in elderly obese patients with colon cancer and does not worsen their prognosis. There was no significant difference in the effectiveness of laparoscopic surgery between obese patients who were elderly and those who were nonelderly.

A case of sigmoid colon perforation due to segmental absence of intestinal musculature (SAIM) accompanied by vascular Ehlers-Danlos syndrome: a case report.

BACKGROUND: Segmental absence of intestinal musculature (SAIM) is a partial defect of the intrinsic muscular layer of the intestinal tract. In this report, we describe a case of perforation of the sigmoid colon due to SAIM accompanied by vascular Ehlers-Danlos syndrome (vEDS), which was successfully treated by surgical therapy. CASE PRESENTATION: A male in his 30 s was being followed up for vEDS diagnosed by genetic testing. He had undergone two major vascular surgeries, abdominal aortic artery revascularization and thoracic endovascular aortic repair for a residual dissection and enlarging abdominal aortic aneurysm. On postoperative day 11, the patient developed perforation of the sigmoid colon for which intraperitoneal lavage and drainage, Hartmann surgery, and transverse colostomy were performed. Histological findings showed no disturbance of blood flow or diverticulum but did show a defect in the intrinsic muscular layer around the perforation site, leading to the pathological diagnosis of SAIM and associated perforation of the sigmoid colon. Postoperatively, the patient had no complications and was discharged on postoperative day 18. The patient is being followed as an outpatient and has experienced no relapse. CONCLUSIONS: Both SAIM and vEDS, which may be related diseases, are associated with the presence of tissue fragility and have a high potential to cause intestinal perforation Caution should be exercised during surveillance in patients with constipation and examinations that cause increased intestinal pressure.

The clinical impact of COVID-19 on endoscopic surgery in Japan: Analysis of data from the National Clinical Database.

Aim: This study aimed to evaluate the impact of the coronavirus disease (COVID-19) pandemic on elective endoscopic surgeries in Japan using the National Clinical Database. Methods: We retrospectively analyzed the clinicopathological factors and surgical outcomes of laparoscopic cholecystectomy (LC), laparoscopic distal gastrectomy (LDG), and laparoscopic low anterior resection (LLAR) and compared the monthly numbers of each procedure performed in 2020 with those in 2018 and 2019. The degree of infection in prefectures was classified into low and high groups. Results: In 2020, the number of LCs (except for acute cholecystitis) was 76 079 (93.0% of that in 2019), the number of LDGs was 14 271 (85.9% of that in 2019), and the number of LLARs was 19 570 (88.1% of that in 2019). Although the number of robot-assisted LDG and LLAR cases increased in 2020, the growth rate was mild compared with that in 2019. There was little difference in the number of cases in the degree of infection in the prefectures. The numbers of LC, LDG, and LLAR cases decreased from May to June and recovered gradually. In late 2020, the proportion of T4 and N2 cases of gastric cancer and the number of T4 cases of rectal cancer increased compared with those in 2019. There was little difference between the proportions of postoperative complications and mortality in the three procedures between 2019 and 2020. Conclusion: The number of endoscopic surgeries decreased in 2020 as a result of the COVID-19 pandemic. However, the procedures were performed safely in Japan.

Laparoscopic versus open resection for stage II/III rectal cancer in obese patients: A multicenter propensity score-based analysis of short- and long-term outcomes.

Aim: Whether a laparoscopic procedure can contribute to the improvement of clinical outcomes in obese patients with stage II/III rectal cancer compared to an open procedure remains unclear. Objective: This study evaluated the technical and oncological safety of laparoscopic surgery versus open surgery in obese patients (body mass index [BMI] ≥25 kg/m2) with rectal cancer. Patients and Methods: Data were collected from patients with pathological stage II/III rectal cancer and analyzed. Operations were performed via laparoscopic or open surgery from 2009 to 2013. A comparative analysis was performed after applying propensity score matching to the two cohorts (laparoscopic group and open group). The primary endpoint was 3-y relapse-free survival (RFS). Results: Overall, 524 eligible cases were collected from 51 institutions. Equal numbers of propensity score-matched patients were included in the laparoscopic (n = 193) group and open (n = 193) group. Although the rate of D3 lymph node dissection did not differ between the laparoscopic group (87.0%) and the open group (88.6%), the median number of harvested lymph nodes was significantly lower in the laparoscopic group versus open group (17.5 vs 21, P = 0.0047). The median postoperative hospital stay was also significantly shorter in the laparoscopic group (14 d) vs the open group (17 d) (P = 0.0014). Three-y RFS was not significantly different between the two groups (hazard ratio 1.2454, 95% confidence interval 0.9201-1.6884, P = 0.4689). Conclusion: The short- and long-term results of this large cohort study (UMIN ID: UMIN000033529) indicated that laparoscopic surgery in obese rectal cancer patients has advantageous short-term outcomes and no disadvantageous long-term outcomes.

Success rate of acquiring informed consent and barriers to participation in a randomized controlled trial of laparoscopic versus open surgery for non-curative stage IV colon cancer in Japan (JCOG1107).

BACKGROUND: Successful achievement of randomized controlled trials (RCTs) is dependent on the acquisition of informed consent (IC) from patients. The aim of this study was to prospectively calculate the proportion of participation in a surgical RCT and to identify the reasons for failed acquisition of IC. METHODS: A 50-insitution RCT was conducted to evaluate oncological outcomes of open and laparoscopic surgery for stage IV colon cancer (JCOG1107: UMIN-CTR 000000105). The success rate of obtaining IC was evaluated in eight periods between January 2013 and January 2021. In addition, reasons for failed acquisition of IC were identified from questionnaires. RESULTS: In total, 391 patients were informed of their eligibility for the trial, and 168 (42%) were randomly assigned to either the laparoscopic surgery group (n = 84) or open surgery group (n = 84). The success rate of IC acquisition ranged from 33 to 58% in three periods. The most common reasons for failed IC acquisition were the patients' preference for one approach of surgery based on recommendations from referring doctors and family members, and anxiety/unhappiness about randomization. CONCLUSIONS: The success rate of acquiring IC from patients for an RCT of laparoscopic versus open surgery for stage IV colon cancer was lower than the expected rate planned in the protocol. To obtain the planned rate, investigators should make efforts to inform patients and their families about the medical contributions a surgical RCT can make and recognize that the period in equipoise may be limited.

Intussusception in the ascending colon caused by cecal chronic diverticulitis: a case report.

Although intussusception in adults generally results from malignant tumors and polyps, intussusception caused by chronic diverticulitis is extremely rare. We present the case of a 59-year-old man treated with steroids and biopharmaceuticals at the Department of Dermatology for psoriasis vulgaris. Cecal diverticulitis frequently recurred, for which he was treated during follow-up. This time, endoscopy showed a circumferential stenosis in the ascending colon, and computed tomography showed the appearance of a target sign in the right colon. As a result, the patient was preoperatively diagnosed as having intussusception of the ascending colon triggered by diverticulitis of the cecum and underwent laparoscopic right colectomy. Pathological findings of the specimen revealed multiple diverticulitis of the cecum. Therefore, we thought that the intussusception was caused by chronic inflammation of the diverticula and surrounding fibrosis. Among intussusception in adults, chronic diverticulitis should be considered as a target of surgical treatment on rare occasions.

Establishment and validation of a nomogram for predicting potential lateral pelvic lymph node metastasis in low rectal cancer.

BACKGROUND: Identifying lateral pelvic lymph node (LPN) metastasis in low rectal cancer is crucial before treatment. Several risk factors and prediction models for LPN metastasis have been reported. However, there is no useful tool to accurately predict LPN metastasis. Therefore, we aimed to construct a nomogram for predicting LPN metastasis in rectal cancer. METHODS: We analyzed the risk factors for potential LPN metastasis by logistic regression analysis in 705 patients who underwent primary resection of low rectal cancer. We included patients at 49 institutes of the Japan Society of Laparoscopic Colorectal Surgery between June 2010 and February 2012. Clinicopathological factors and magnetic resonance imaging findings were evaluated. The nomogram performance was assessed using the c-index and calibration plots, and the nomogram was validated using an external cohort. RESULTS: In the univariable logistic regression analysis, age, sex, carcinoembryonic antigen, tumor location, clinical T stage, tumor size, circumferential resection margin (CRM), extramural vascular invasion (EMVI), and the short and long axes of LPN and perirectal lymph node (PRLN) were nominated as risk factors for potential LPN metastasis. We identified a combination of the short axis of LPN, tumor location, EMVI, and short axis of PRLN as optimal for predicting potential LPN metastasis and developed a nomogram using these factors. This model had a c-index of 0.74 and was moderately calibrated and well-validated. CONCLUSIONS: This is the first study to construct a well-validated nomogram for predicting potential LPN metastasis in rectal cancer, and its performance was high.

Challenges needed to be overcome in multi-institutional surgical trials: accumulated experience in the JCOG Colorectal Cancer Study Group (CCSG).

JCOG-CCSG has been conducting several surgical trials and experienced several challenges. The first point is the appropriate timing of conducting the trial. Once a certain number of surgeons acquire the new technique and its utility is accepted, it suddenly becomes difficult to maintain 'equipoise' between the standard and new treatment, which may lead to poor patient accrual. Smooth preparation and commencement of the trial at an appropriate timing is necessary for its success. Second is the appropriate quality assurance of surgery. High-level quality assurance will strengthen the comparability of randomized control trials and minimize the heterogeneity among hospitals. On the other hand, it may impair the generalizability of the trial. Large observational studies help to bridge the gap of heterogeneity among hospitals. Third is the selection of an appropriate endpoint. Overall survival (OS) is the gold-standard primary endpoint; however, the number of events is much less due to more effective treatment. JCOG0212 and JCOG0404 were unable to demonstrate the non-inferiority of omission of lateral lymph node dissection and laparoscopic surgery partly due to a lack of power. Disease-free survival (DFS) is also a promising candidate for primary endpoint, but as in JCOG0603, special attention must be paid when DFS does not correlate with OS. Although careful discussion is required because the precision of the hazard ratio depends on the number of events, an alternative population-level summary of variables, including restricted mean survival time, can be considered as the primary endpoint. Future surgical trials should be planned considering these points.

Impact of Endoscopic Surgical Skill Qualification on Laparoscopic Resections for Rectal Cancer in Japan: The EnSSURE Study.

Objective: This cohort study investigated short- and long-term postoperative outcomes of laparoscopic procedures for rectal cancer performed with versus without certified surgeons. Background: In Japan, the Endoscopic Surgical Skill Qualification System (ESSQS) evaluates surgical skills deemed essential for laparoscopic surgery; however, it is unknown whether this certification contributes to procedural safety. Methods: Outcomes of laparoscopic rectal resections for cStage II and III rectal cancer performed from 2014 to 2016 at 56 Japanese hospitals were retrospectively reviewed. The impact of having versus not having certified surgeons on postoperative complications and other short- and long-term outcomes were assessed. In cases with ESSQS-certified surgeons, surgeons attended surgery in the capacity of an operator, assistant, scope operator, or advisor. Results: Overall, 3188 procedures were analyzed, with 2644 procedures performed with and 544 without ESSQS-certified surgeons. A multivariate logistic regression model showed that the adjusted odds ratio of postoperative complications after procedures performed with ESSQS-certified surgeons was 0.68 (95% confidence interval, 0.51-0.91; P = 0.009). The adjusted odds ratios for conversion and pathological R0 resection rates with ESSQS-certified surgeons were 0.20 (P < 0.001) and 2.10 (P = 0.04), respectively. Multiple linear regression analyses showed significantly shorter surgical duration and more harvested lymph nodes for operations performed with ESSQS-certified surgeons. Multivariate Cox regression showed that the adjusted hazard ratios for poor overall and recurrence-free survival after operations performed with ESSQS-certified surgeons were 0.88 (P = 0.35) and 1.04 (P = 0.71), respectively. Conclusions: This study showed the superiority of the short-term postoperative results for laparoscopic rectal procedures performed with ESSQS-certified surgeons.

Current Status of Endoscopic Surgery in Japan: The 15th National Survey of Endoscopic Surgery by the Japan Society for Endoscopic Surgery.

In Japan, the first endoscopic surgery, a laparoscopic cholecystectomy, was performed in 1990. Since then, operative procedures have been standardized, and the safety and efficacy of endoscopic surgery have been evaluated. In accordance with the social acceptance of endoscopic surgery as a less invasive type of surgery, the number of endoscopic procedures performed has increased in all surgical domains. The Japan Society for Endoscopic Surgery (JSES) has played an important role in the development of endoscopic surgery in Japan. Notably, a technical skills certification system for surgeons was established by the JSES to train instructors on how to teach safe endoscopic surgery. Furthermore, the JSES has conducted a national survey every 2 years. In 2019, 291,792 patients underwent endoscopic surgery in all surgical domains, such as abdominal, thoracic, mammary and thyroid gland, cardiovascular, obstetrics and gynecology, urologic, orthopedic, and plastic surgery. The 15th National Survey of Endoscopic Surgery conducted by the JSES demonstrated the status of laparoscopic surgery in Japan in 2018-2019.

Identification of patient subgroups with unfavorable long-term outcomes associated with laparoscopic surgery in a randomized controlled trial comparing open and laparoscopic surgery for colon cancer (Japan Clinical Oncology Group Study JCOG0404).

BACKGROUND: Previously, we conducted a randomized controlled trial (JCOG0404) for stage II/III colon cancer patients and reported that the long-term survival after open surgery (OP) and laparoscopic surgery (LAP) were almost identical; however, JCOG0404 suggested that survival of patients after LAP with tumors located in the rectosigmoid colon, cT4 or cN2 tumors, and high body mass index (BMI) might be unfavorable. AIM: To identify the patient subgroups associated with poor long-term survival in the LAP arm compared with the OP arm. METHODS: Patients aged 20-75, clinical T3 or deeper lesion without involvement of other organs, clinical N0-2 and M0 were included. The patients with pathological stage IV and R2 resection were excluded from the current analysis. In each subgroup, the hazard ratio for LAP (vs. OP) in overall survival (OS) from surgery was estimated using a multivariable Cox regression model adjusted for the clinical and pathological factors. RESULTS: In total, 1025 patients (OP, 511 and LAP, 514) were included in the current analysis. Adjusted hazards ratios for OS of patients with high BMI (>25 kg/m2), pT4, and pN2 in LAP were 3.37 (95% confidence interval [CI], 1.24-9.19), 1.33 (0.73-2.41), and 1.74 (0.76-3.97), respectively. In contrast, that of rectosigmoid colon tumors was 0.98 (0.46-2.09). CONCLUSIONS: Although LAP is an acceptable optional treatment for stage II/III colon cancer, the present subgroup analysis suggests that high BMI (>25 kg/m2), pT4, and pN2 except for RS were factors associated with unfavorable long-term outcomes of LAP in patients with colon cancer who underwent curative resection. (JCOG 0404: NCT00147134/UMIN-CTR: C000000105.).

Institutional variation in survival and morbidity in laparoscopic surgery for colon cancer: From the data of a randomized controlled trial comparing open and laparoscopic surgery (JCOG0404).

BACKGROUND: Institutional variation in outcomes is a key factor to ascertain the generalizability of results and reliability of the clinical trial. This study evaluated institutional variation in survival and postoperative complications using data from JCOG0404 comparing laparoscopic colectomy (LAP) with open colectomy (OP). METHODS: Institutions with fewer than 10 registered patients were excluded from this analysis. Institutional variation was evaluated in terms of early postoperative complications, overall survival, and relapse-free survival and estimated using a mixed-effect model with institution as a random effect after adjusting for background factors. RESULTS: This analysis included 1028 patients in the safety analysis and 1040 patients in the efficacy analysis from 26 institutions. In the safety analysis, there was no variation in grades 3-4 early postoperative complications (in OP, median 6.3% [range 6.3%-6.3%]; in LAP, median 2.6% [range 2.6%-2.6%]), but some variation in grades 1-4 early postoperative complications was observed (in OP, median 20.8% [range 13.2%-31.8%]; in LAP, median 11.9% [range 7.2%-28.7%]), and that in grades 2-4 was observed only in LAP (median 8.8% [range 4.7%-24.0%]; in OP, median 12.7% [range 12.7%-12.7%]). Two specific institutions showed especially high incidences of postoperative complications in LAP. In the efficacy analysis, there was no institutional variation in OP, although a certain variation was observed in LAP. CONCLUSIONS: Some institutional variations in safety and efficacy were observed, although only in LAP. We conclude that a qualification system, including training and education, is needed when new surgical techniques such as laparoscopic surgery are introduced in clinical practice.

Prognostic Impact of Lateral Pelvic Node Dissection on the Survival of Patients in Low Rectal Cancer Subgroups Based on Lymph Node Size.

BACKGROUND: Lateral pelvic node (LPN) dissection (LPND) is considered a promising technique for treating low rectal cancer; however, there is insufficient evidence of its prognostic value. Using centrally reviewed preoperative pelvic magnetic resonance (MR) images, this study aimed to find the patient population who has benefited from LPND. PATIENTS AND METHODS: MR images of patients from 69 institutes with stage II-III low rectal cancer were reviewed by experienced radiologists. Recurrence-free survival (RFS), overall survival (OS), and short-term outcomes were measured. RESULTS: In total, 731 preoperative MR images were reviewed (excluding patients with short-axis LPN ≥ 10 mm). Of these, 322 underwent total mesorectum excision (TME) without LPND (non-LPND group), and 409 underwent TME with LPND (LPND group). Preoperative treatment was performed for 40% and 25% of patients in the non-LPND and LPND groups, respectively. The incidence of postoperative complications was higher in the LPND group (44.5%) than in the non-LPND group (33.2%; P = 0.002). Among patients with LPNs < 5 mm, OS and RFS curves were not significantly different between the groups. Among patients with LPNs ≥ 5 mm, the LPND group had significantly higher 5-year OS and RFS than the non-LPND group (OS: 81.9% versus 67.3%; RFS: 69.4% versus 51.6%). On multivariate analysis of LPN ≥ 5 mm cases, LPND was independently associated with RFS. CONCLUSIONS: Despite the high incidence of postoperative complications, this study showed the prognostic impact of LPND on low rectal cancer patients with LPNs (≥ 5 mm, < 10 mm short axis) measured by experienced radiologists. Trial registration UMIN-ID: UMIN000013919.

Early response in phosphorylation of ribosomal protein S6 is associated with sensitivity to trametinib in colorectal cancer cells.

Mutations in RAS or BRAF are associated with poor prognosis and resistance to epidermal growth factor receptor (EGFR)-targeted therapy in colorectal cancer (CRC). Despite their common ability to activate downstream genes such as MEK and ERK, the therapeutic benefit of MEK inhibitors for patients with RAS/BRAF mutant CRC is limited, highlighting the need for biomarkers to predict the efficacy of MEK inhibition. Previously, we reported that a change in phosphorylation of ribosomal protein S6 (pS6) after MEK inhibition was significantly associated with sensitivity to MEK inhibition in gastric cancer cells. Here, we investigated the value of the response in pS6 for predicting the efficacy of trametinib, a MEK inhibitor, in patients with RAS/BRAF mutant CRC using patient-derived CRC organoids. We found that a subset of CRC cell lines and organoids were sensitive to trametinib. The change in phosphorylated ERK, a downstream molecule of the RAS/RAF/MEK pathway, was not significantly associated with trametinib sensitivity. On the other hand, only those with sensitivity showed a reduction of pS6 levels in response to trametinib. The change in pS6 after trametinib treatment was detectable by Western blotting, immunohistochemistry or immunocytochemistry. We also demonstrated an impact of MEK inhibition on pS6 in vivo using a xenograft model. Our data suggest that, in combination with patient-derived organoids, immunostaining-based detection of pS6 could be useful for prediction of trametinib sensitivity.