Akio Shiomi

BACKGROUND: JCOG1107 (UMIN-CTR, number UMIN000009715) was a non-inferiority phase III trial comparing laparoscopic and open surgery for symptomatic, non-curable stage IV colon cancer. The primary analysis confirmed the non-inferiority of laparoscopic surgery in terms of progression-free survival. OBJECTIVE: To compare long-term outcomes of laparoscopic and open surgery for stage IV colon cancer. DESIGN: Multicenter, open-label, randomized, controlled phase III trial. SETTING: Forty-two Japanese institutions. PATIENTS: Participants were considered eligible if they had pathologically confirmed adenocarcinoma or adenosquamous carcinoma with a primary tumor between the cecum and rectosigmoid, presenting with stenosis and/or bleeding, and one to three non-curable factors. The required sample size was 194 to ensure 70% power, a one-sided alpha of 5%, and a non-inferiority hazard ratio margin of 1.38. INTERVENTIONS: Patients were randomized to receive either open or laparoscopic primary tumor resection, followed by modified FOLFOX6 plus bevacizumab or capecitabine plus oxaliplatin with bevacizumab. MAIN OUTCOME MEASURES: The primary endpoint was progression-free survival. RESULTS: A total of 195 patients were randomized, including 95 open and 100 laparoscopic surgeries. Postoperative chemotherapy was given to 82 and 86 patients, respectively. The median follow-up period for all randomized patients was 24.4 months. Grade ≥3 late complications occurred in one open (1.1%) and two laparoscopic (2.0%) patients. Three-year progression-free survival was 5.3% (95% confidence interval: 2.0–11.0) for open surgery and 3.0% (0.8–7.8) for laparoscopic surgery (hazard ratio: 1.028; 95% confidence interval: 0.772–1.370; p for non-inferiority = 0.02). The three-year overall survival was 31.5% (22.5–41.0) and 28.5% (20.0–37.6) (hazard ratio: 1.048; 95% confidence interval: 0.780–1.410), respectively. LIMITATIONS: Chemotherapy was administered without knowledge of microsatellite instability or RAS/BRAF mutation status. CONCLUSION: Laparoscopic surgery is non-inferior to open surgery for non-curable stage IV colon cancer and should be considered an acceptable surgical option. See Video Abstract .

The lymph node metastasis (LNM) rate of submucosal invasive colorectal cancer (pT1 CRC) is low (approximately 10%), even when the risk factors for LNM outlined in the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines for endoscopically resected lesions are present. To ensure that patients receive appropriate treatment, novel factors that link endoscopic and pathological diagnoses and more accurately predict LNM are needed. Polypoid growth (PG)/non-polypoid growth (NPG) classification, depth of submucosal invasion and stalk status are examples of such interconnected factors. This study investigated the association between LNM and the histological PG (hPG)/NPG (hNPG) classification in pT1 CRC. A total of 1059 consecutive cases with both sessile and pedunculated pT1 CRCs were examined. LNM was present in 126 (11.9%) patients. The hPG and hNPG types were observed in 49% (519/1059) and 51% (540/1059) of cases, respectively. Cohen's kappa coefficient for intra- and inter-observer agreement was 0.78. Multivariate analysis identified hNPG type (p < 0.001), positive lymphovascular invasion (LVI) (p < 0.001) and budding grade (BD) 2/3 (p < 0.001) as independent predictors of LNM. A new algorithm incorporating these three factors increased the predicted LNM rate to 16.0%, yielded an LNM prediction rate of 11.9%, compared with the 12.5% rate of the JSCCR algorithm. Notably, no LNM occurred in hPG lesions with negative LVI and BD 1, indicating that 25.8% (273/1059) of patients could have avoided additional surgery. Thus, hPG/hNPG classification may provide a simple and reproducible tool for refining LNM risk stratification in pT1 CRC.

Transverse colon cancer is traditionally treated with extended right hemicolectomy (EHC), which involves division of the middle colic, right colic, and ileocolic arteries, along with removal of the terminal ileum and right colon. Transverse colectomy (TC) is a limited resection removing only 10 cm of bowel on either side of the tumor, along with resection of the middle colic artery and regional lymphadenectomy. This approach may contribute to the preservation of bowel function without compromising oncologic adequacy. This multicenter, randomized, phase III trial is designed to evaluate the non-inferiority of TC compared with EHC in terms of relapse-free survival among patients with Stage II/III transverse colon cancer whose main feeding artery is the middle colic artery. In total, 510 patients will be enrolled across major Japanese centers over 5 years. The trial has been registered with the Japan Registry of Clinical Trials (jRCT1030240479).

Aim: Using data from the LANDMARC study, we aimed to evaluate the impacts of abdominoperineal resection (APR) on postoperative sexual function in males with rectal cancer undergoing minimally invasive surgery. Methods: Patients were categorized into the APR ( n = 44) and anal‐sparing surgery (AS) groups ( n = 329). A detailed subgroup analysis was performed in patients with tumors located < 5 cm from the anal verge (APR, n = 39; AS, n = 59). Sexual function was assessed preoperatively and at 3, 6, and 12 months postoperatively using the International Index of Erectile Function‐5 (IIEF‐5), Erection Hardness Score (EHS), and a customized questionnaire for ejaculatory function. Propensity score–based logistic regression models and longitudinal analyses were applied to address significant baseline imbalances. Results: In the overall cohort, APR was independently associated with significantly impaired erectile function. Adjusted models showed higher predicted probabilities of erectile dysfunction (ErD) after APR at 3 months (38.7% vs. 16.8) and 12 months (34.7% vs. 13.7%). Longitudinal analyses confirmed increased odds of ErD at 3 months (OR 2.86; 95% CI 1.25–6.53) and 12 months (OR 3.05; 95% CI 1.30–7.14). Potency impairment was also significantly more frequent at 3 months. Ejaculatory dysfunction was more common after APR early postoperatively. In patients with tumors located < 5 cm from the anal verge, APR remained associated with impaired erectile function, whereas ejaculatory function showed partial recovery. Conclusion: Results suggest that APR is associated with a high risk of postoperative sexual dysfunction, even in minimally invasive surgery. Sexual function preservation is an important consideration when APR is considered.

Background: This study aimed to evaluate the clinical utility and prognostic significance of sarcopenia classification based on the psoas major muscle volume index (PVI) in elderly patients with rectal cancer. Methods: We retrospectively analyzed 428 patients aged ≥ 65 years who underwent laparoscopic or robot‐assisted radical rectal cancer resection between 2014 and 2018. PVI was calculated by dividing the semi‐automatically measured psoas major muscle volume on three‐dimensional computed tomography (CT) by the cube of height (m ³ ). Sex‐specific PVI cutoff values for 5‐year overall survival (OS) were determined using time‐dependent receiver operating characteristic analysis. Associations between PVI, nutritional and inflammatory markers, conventional sarcopenia indices, and long‐term outcomes were investigated. Results: PVI cut‐off values were ≤ 58.9 cm ³ /m ³ for males and ≤ 39.9 cm ³ /m ³ for females. Patients with low PVI had significantly worse nutritional and inflammatory profiles. The 5‐year OS (86.6% vs. 94.6%, p = 0.001), cancer‐specific survival (93.5% vs. 97.4%, p = 0.003), and relapse‐free survival (76.2% vs. 85.4%, p = 0.021) were significantly lower in the low PVI group than in the normal‐high PVI group. Multivariate analysis identified low PVI (hazard ratio: 2.55; p = 0.012) and Prognostic Nutritional Index < 40 as independent predictors of poor OS. Conclusion: PVI‐based sarcopenia classification reflects nutritional and inflammatory status and enables effective prognostic stratification in elderly patients with rectal cancer. It may serve as a simple and objective tool for preoperative risk assessment, offering improved prognostic stratification compared with conventional CT‐based indices.

The number of deaths from colorectal cancer in Japan continues to rise, with over 50,000 deaths recorded in 2018. In the 2024 edition, revisions to all aspects of treatment were undertaken, with corrections and additions made based on knowledge gained since the 2022 version (drug therapy) and the 2019 version (other treatments). The Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2024 for the treatment of colorectal cancer have been prepared to present standard treatment strategies, reduce disparities among institutions, avoid both unnecessary and insufficient treatment, and enhance mutual understanding between healthcare professionals and patients by making these guidelines accessible to the public. These guidelines were developed through consensus by the JSCCR Guideline Committee, following a careful review of evidence retrieved from literature searches and considering the medical insurance system and actual clinical practice in Japan. Therefore, these guidelines serve as a tool for managing colorectal cancer in real-world clinical settings. More specifically, they can be used to support obtaining informed consent from patients and selecting the most appropriate treatment method for each patient. Controversial topics were selected as clinical questions, and recommendations were provided. Each recommendation is accompanied by an evidence classification and a recommendation category, both based on consensus reached by the Guideline Committee members. This article presents the English version of the JSCCR guidelines 2024.

Background/Aim: To date, several clinical trials have compared isoperistaltic and antiperistaltic anastomosis; however, in the context of robot-assisted surgery (RAS), a consensus on the optimal approach has yet to be established. This study aimed to compare the short-term outcomes of intracorporeal isoperistaltic and antiperistaltic side-to-side anastomoses in RAS for right-sided colon cancer. Patients and Methods: A retrospective subgroup analysis was conducted using a database collected from a Japanese multicenter prospective study. Patients diagnosed with curatively resectable right-sided colon cancer (cStage I-IIIC) who underwent RAS with intracorporeal anastomosis were included. Surgical and postoperative outcomes were compared between the isoperistaltic and antiperistaltic anastomosis groups. Results: Among the 78 patients analyzed, 23 (29.5%) underwent antiperistaltic anastomosis and 55 (70.5%) underwent isoperistaltic anastomosis. There were no significant differences in age, sex, American Society of Anesthesiologists Physical Status score, previous abdominal surgical history, or clinical stage between the groups. Isoperistaltic anastomosis was more frequently performed in ascending and transverse colon cancers, whereas antiperistaltic anastomosis was more frequent in cecal cancers. Right hemicolectomy was significantly more frequent in the isoperistaltic group than in the antiperistaltic group (92.7% vs. 60.9%) (p=0.0014). The total operative time was longer in the antiperistaltic group, but the console and anastomosis times were comparable. No intraoperative complications, conversions, or transfusions were reported. Postoperative complication rates were similar between the two groups. Conclusion: This study demonstrated equivalent short-term outcomes between intracorporeal isoperistaltic and antiperistaltic anastomoses in RAS for right-sided colon cancer. Both techniques appear to be safe and effective, supporting the recommendation that surgeons maintain proficiency in both methods to allow flexibility based on intraoperative conditions.

Aim: Perineal wound infection (PWI) is a critical complication unique to abdominoperineal resection (APR) that requires preventive interventions. This study compared the efficacy of a 4‐day regimen of sulbactam/ampicillin (SBT/ABPC) with that of a 1‐day regimen of cefmetazole (CMZ) for preventing PWI after APR. Methods: Eighty patients who underwent APR for rectal cancer were enrolled in this multicenter, open‐label, randomized controlled trial. The primary outcome was the incidence of PWI, and secondary outcomes included the incidence of surgical site infections (SSI), other complications, and length of postoperative hospital stay. Based on an assumed PWI incidence of 46% for CMZ and 14% for SBT/ABPC, a sample size of 40 participants per group was required to achieve a 90% power at a two‐sided 10% significance level. Results: Of the 80 randomized patients, 76 were analyzed in the SBT/ABPC ( n = 39) and CMZ ( n = 37) groups. The incidence of PWI (10.3% vs. 24.3%, respectively; p = 0.096) was significantly lower in the SBT/ABPC group than in the CMZ group, based on a planned two‐sided significance level of 10%. SSI, other complications, including antibiotic‐related adverse events, and length of postoperative hospital stay, were not significantly different between the two groups. SBT/ABPC demonstrated broader bacterial coverage than CMZ in the PWI treatment. Conclusion: The 4‐day SBT/ABPC regimen significantly reduced the incidence of PWI after APR compared to the 1‐day CMZ regimen. This simple approach to antibiotic selection may be beneficial for preventing PWI.

Aim: Few reports have described pelvic reinforcement procedure ( PRP ) to prevent perineal hernia ( PH ) in robotic abdominoperineal resection (Ro‐ APR ) for rectal cancer. This study aimed to investigate the safety and efficacy of PRP in Ro‐ APR . Methods: Patients who underwent Ro‐APR for rectal cancer between January 2020 and June 2023 were retrospectively examined. PRP was performed as a prophylactic procedure for PH. Four types of PRP were performed depending on the case (closure of the levator ani muscles, the pelvic peritoneum with the uterus, the pelvic peritoneum, and the pelvic peritoneum with a bladder peritoneal flap). Background factors and surgical outcomes were compared between patients without PRP (PRP−) and with PRP (PRP+). Imaged PH was diagnosed using computed tomography 1 year postoperatively. Imaged PH with symptoms was defined as symptomatic PH. Results: We evaluated 81 patients, including 51 PRP− (63.0%) and 30 PRP+ (37.0%). There were no differences in the characteristics between the two groups. There was no significant difference in operative time between the two groups (358 min vs. 329 min, p = 0.460). PRP− had a significantly higher rate of imaged PH (39.2% vs. 6.7%, p = 0.005) and symptomatic PH (19.6% vs. 3.3%, p = 0.047). The two groups had no significant differences in the other postoperative complications. In multivariate analysis, the independent risk factor for PH was not undergoing PRP (odds ratio 9.71, p = 0.005). Conclusion: PRP in Ro‐APR for rectal cancer can be safely performed and helps prevent PH.