Journal of the Anus Rectum and Colon最新文献

{"title":"Characteristics and Surgical Outcomes of Patients with Intestinal Endometriosis Undergoing Bowel Resection.","authors":"Hisashi Ro, Yutaka Kojima, Makoto Takahashi, Kiichi Sugimoto, Shun Ishiyama, Masaya Kawai, Kumpei Honjo, Shiori Takeuchi, Yu Kawasaki, Keisuke Murakami, Mari Kitade, Kazuhiro Sakamoto","doi":"10.23922/jarc.2025-037","DOIUrl":"10.23922/jarc.2025-037","url":null,"abstract":"<p><strong>Objective: </strong>To retrospectively evaluate the clinical features, perioperative findings, and long-term outcomes of patients who underwent bowel resection for intestinal endometriosis, and to clarify diagnostic and therapeutic challenges with the goal of supporting optimal surgical strategies that minimize recurrence while preserving function.</p><p><strong>Methods: </strong>Twenty-one patients who underwent bowel resection for intestinal endometriosis from 2002 to 2022 were evaluated regarding clinicopathological findings and short and long-term outcomes.</p><p><strong>Results: </strong>The median age was 38 years. All patients had gastrointestinal symptoms. Colonoscopy confirmed endometriosis histologically in only 1 patient (7.1%). Lesions were identified in the sigmoid colon to the upper rectum in 17 patients, some of which were accompanied by obliteration of the pouch of Douglas. Low anterior resection was performed in 15 of these patients, and temporary stomas were created in 4 patients. Gynecologic procedures were performed in 9 patients. Histopathology showed invasion into the submucosal and muscular layers. Early complications (Clavien-Dindo ≥2) occurred in 2 patients (anastomotic leak and ileus), while late complications included anastomotic stenosis, bowel stricture, and rectovaginal fistula (1 patient each). Only one recurrence (4.8%) was observed during a median follow-up of 2,088 days. Spontaneous pregnancy was achieved in 2 patients.</p><p><strong>Conclusions: </strong>This study highlights the clinical significance of bowel resection for intestinal endometriosis, suggesting the importance of comprehensive evaluation to improve diagnostic accuracy, the utility of collaboration with gynecology, and the potential for recurrence reduction and functional preservation through appropriate resection margins. These findings may contribute to the development of future treatment strategies for this condition.</p>","PeriodicalId":56349,"journal":{"name":"Journal of the Anus Rectum and Colon","volume":"10 1","pages":"8-18"},"PeriodicalIF":1.5,"publicationDate":"2026-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12854292/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146108533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Risk Factors for Colostomy after Chemoradiotherapy in Patients with Squamous Cell Carcinoma of the Anus: A Nationwide, Multicenter Analysis in Japan.","authors":"Atsushi Kohyama, Shinobu Ohnuma, Michiaki Unno, Yoichi Ajioka, Kenichi Sugihara, Kazutaka Yamada","doi":"10.23922/jarc.2025-029","DOIUrl":"10.23922/jarc.2025-029","url":null,"abstract":"<p><strong>Objectives: </strong>This study investigated the incidence of colostomy, aiming to identify its risk factors following chemoradiotherapy (CRT) for squamous cell carcinoma of the anus (SCCA) in a large Asian cohort, and to clarify the prognostic significance of a complete response (CR). While CRT is the standard of care for SCCA, the risk of colostomy remains a major concern due to its potential impact on a patient's quality of life. Prior studies focused mainly on Western populations, and data from Asian cohorts are limited.</p><p><strong>Methods: </strong>We conducted a retrospective multicenter study of 246 patients with SCCA who underwent CRT at 47 Japanese Society for Cancer of the Colon and Rectum (JSCCR)-affiliated institutions-the largest Asian cohort analyzed to date. Colostomy incidence, colostomy-free survival (CFS), and associated risk factors were assessed.</p><p><strong>Results: </strong>Consistent with earlier Western reports, the 5-year cumulative colostomy incidence was 20.4% and the CFS rate was 65.9%. Multivariable analysis identified tumor size >50 mm (HR 9.619, P=0.0026) and male sex (HR 5.170, P<0.0001) as independent predictors of colostomy. Failure to achieve CR was strongly associated with higher colostomy risk (HR 3.732, P<0.0001), and local recurrence after CR further increased this risk (HR 16.302, P<0.0001).</p><p><strong>Conclusions: </strong>In this largest Asian cohort to date of patients with SCCA treated with CRT, tumor size, male sex, and abscence of CR emerged as key predictors of colostomy. Early identification of high-risk patients and achieving CR are essential for improving anal preservation and guiding individualized treatment strategies.</p>","PeriodicalId":56349,"journal":{"name":"Journal of the Anus Rectum and Colon","volume":"10 1","pages":"43-53"},"PeriodicalIF":1.5,"publicationDate":"2026-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12854289/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146108668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Reduction of Early Postoperative Anal Pain following Hemorrhoid Surgery with Epidural Anesthesia: A Pilot Study.","authors":"Ryota Koyama, Gentaro Ishiyama, Akihiko Nishio, Takuro Kyuno, Aya Sato, Emi Akizuki, Yuji Ishiyama","doi":"10.23922/jarc.2025-011","DOIUrl":"10.23922/jarc.2025-011","url":null,"abstract":"<p><strong>Objectives: </strong>Hemorrhoids commonly occur worldwide, and surgical intervention is required in severe cases. However, a method for postoperative pain control is yet to be established. In this study, we developed a caudal epidural anesthesia tube placement method and demonstrated its meaningful outcomes.</p><p><strong>Methods: </strong>We postoperatively analyzed 85 patients who underwent hemorrhoid surgery at the Sapporo Ishiyama Hospital. Using a computer-generated method, patients were assigned to the caudal epidural tube placement group (E group; n = 47) or without tube placement group (N group; n = 38) and compared using a numeric rating scale (NRS).</p><p><strong>Results: </strong>Goligher classification grade ≥3 severe hemorrhoids were found in 93% of patients in the study. Anal cushion lifting (ACL), a surgical technique requiring no hemorrhoid resection with or without excision (e.g., Milligan-Morgan hemorrhoidectomy), was used. Swelling was observed in 15% of overall patients, but it was controlled with conservative treatment. Postoperative bleeding occurred in one patient in the N group. The mean duration of caudal epidural tube placement was 33.7 h, and there were no adverse events such as infection. The NRS results showed that the E group had a significantly lower mean NRS score at postoperative 24 and 48 h compared with the N group. No apparent rebound pain after tube removal occurred, and the transition to an oral analgesic was smooth and successful.</p><p><strong>Conclusions: </strong>Our novel method may contribute to the pain management during early periods following hemorrhoidectomy.</p>","PeriodicalId":56349,"journal":{"name":"Journal of the Anus Rectum and Colon","volume":"9 4","pages":"415-419"},"PeriodicalIF":1.5,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12574802/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145432958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preoperative Albumin-bilirubin Score and Colon Inflammatory Index Predict the Prognosis in Colorectal Cancer Patients: A Retrospective Study.","authors":"Akihito Kubota, Yasuhiro Takano, Akitaka Sasaki, Teppei Kamada, Ken Eto","doi":"10.23922/jarc.2025-023","DOIUrl":"10.23922/jarc.2025-023","url":null,"abstract":"<p><strong>Objectives: </strong>The albumin-bilirubin (ALBI) score and colon inflammatory index (CII) are new sensitive scoring systems for several cancers. However, their clinical significance in colorectal cancer remains unclear. This study investigated the significance of ALBI score and CII for prognosis after colorectal cancer surgery.</p><p><strong>Methods: </strong>The present study analyzed data from patients who underwent curative resection for colorectal cancer. We investigated the association between preoperative ALBI score, CII, and disease-free and overall survival following surgery. Univariate and multivariate analyses were conducted to identify independent risk factors for poor prognosis in patients with colorectal cancer.</p><p><strong>Results: </strong>A total of 234 patients were included in the present study. Kaplan-Meier analysis demonstrated that patients with higher ALBI scores and poor CII had significantly worse disease-free and overall survival. In multivariate analysis, ALBI score ≥ -2.45 (P = 0.002), CII poor (P < 0.001), and pathological N1-3 stage (P = 0.017) were independent predictors of disease-free survival. Similarly, ALBI score ≥ -2.45 (P < 0.001 ), CII poor (P = 0.003), and pathological N1-3 stage (P = 0.015) were independent predictors of overall survival.</p><p><strong>Conclusions: </strong>ALBI score and CII were strong predictors of poor prognosis in patients who underwent curative resection for colorectal cancer, emphasizing their potential utility in clinical practice. Incorporating these markers into routine clinical practice may enhance individualized treatment strategies and postoperative surveillance.</p>","PeriodicalId":56349,"journal":{"name":"Journal of the Anus Rectum and Colon","volume":"9 4","pages":"370-377"},"PeriodicalIF":1.5,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12574803/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145433004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ophthalmic Toxicities in BEACON Triplet Therapy for BRAF V600E-Mutant Colorectal Cancer: A Case Series.","authors":"Hayato Nakamura, Kiyoshi Suzumura, Kazuhiro Oiwa, Tomonori Tsuchiya, Kazumi Nishimae, Masahiro Tanaka, Masaki Terasaki, Yoshichika Okamoto","doi":"10.23922/jarc.2025-031","DOIUrl":"10.23922/jarc.2025-031","url":null,"abstract":"<p><p>The BEACON regimen, comprising cetuximab, encorafenib, and binimetinib, is a critical treatment for BRAF-mutant metastatic colorectal cancer (mCRC). While effective, this regimen may be associated with a high frequency of serous retinal detachment (SRD) as an ocular toxicity, which is a less recognized risk in colorectal cancer. Here, we report three patients with mCRC who developed SRD shortly after starting BEACON therapy. Each patient experienced acute visual disturbances, and optical coherence tomography (OCT) confirmed SRD without other retinal abnormalities. Temporary discontinuation of therapy improved the OCT findings in all patients. Two patients resumed treatment with a doublet regimen (excluding binimetinib) and maintained stable vision without irreversible damage. The third patient continued binimetinib with an adjusted dosing schedule of 1 week administration and 1 week off, with no ocular toxicity; the other two drugs were continued. None of the patients experienced permanent vision impairment. These cases highlight the importance of early recognition and proactive management of ocular toxicity in patients receiving BEACON therapy. Regular ophthalmological monitoring and appropriate dose adjustments are essential to prevent visual damage while maintaining treatment efficacy.</p>","PeriodicalId":56349,"journal":{"name":"Journal of the Anus Rectum and Colon","volume":"9 4","pages":"465-471"},"PeriodicalIF":1.5,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12574812/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145432963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two Cases of Low Intersphincteric Anal Fistulas with Intrafistulous Calculi.","authors":"Yoshiyuki Suzuki, Kosuke Okamoto, Joji Kuromizu, Nobuyoshi Miyajima, Yasuhiro Shimojima, Yukihito Kokuba, Naomi Matsumura, Yoichi Kono, Ayumi Beniya, Sayuri Matsushima, Yu Sakai, Makoto Matsushima","doi":"10.23922/jarc.2025-028","DOIUrl":"10.23922/jarc.2025-028","url":null,"abstract":"<p><p>Anal fistulas with intrafistulous calculi are extremely rare. Enterolithiasis generally occurs due to the precipitation, aggregation, and calcification of non-digestible materials; however, its occurrence within anal fistulas remains poorly understood. Here, we report two cases of low intersphincteric anal fistulas with intrafistulous calculi, diagnosed via endoanal ultrasonography and treated surgically. We discuss the possible pathophysiological mechanisms, imaging characteristics, and clinical significance of these calculi.</p>","PeriodicalId":56349,"journal":{"name":"Journal of the Anus Rectum and Colon","volume":"9 4","pages":"455-457"},"PeriodicalIF":1.5,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12574804/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145433011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Short-term Outcomes and Associated Factors of Postoperative Complications following Laparoscopic Ileocecal Resection in Complex Crohn's Disease.","authors":"Eiichi Nakao, Kenji Tatsumi, Nao Obara, Koki Goto, Hirosuke Kuroki, Akira Sugita, Kazutaka Koganei","doi":"10.23922/jarc.2025-018","DOIUrl":"10.23922/jarc.2025-018","url":null,"abstract":"<p><strong>Objectives: </strong>Minimally invasive surgery (MIS) is widely used for Crohn's disease (CD), but its feasibility in complex CD is still debated. This study aimed to evaluate short-term outcomes and identify factors associated with major complications following laparoscopic ileocecal resection in patients with complex CD.</p><p><strong>Methods: </strong>A retrospective study was conducted on patients with complex CD who underwent laparoscopic ileocecal resection. Patients with prior intestinal surgery for CD were excluded to ensure a uniform cohort. Short-term outcomes, including operative time, blood loss, complications, and hospital stay, were compared between patients undergoing laparoscopic (LS) and open surgery (OS). Univariate analysis was performed to assess factors associated with major complications (Clavien-Dindo grade ≥3).</p><p><strong>Results: </strong>A total of 101 patients were included (LS, n=21; OS, n=80). The LS group had significantly lower blood loss (140 vs. 222.5 mL, P=0.048) and shorter postoperative hospitalization (12 vs. 15 days, P=0.0068). No conversions to open surgery were required. There was no significant difference in the incidence of major complications (9.5% vs. 3.8%, P=0.57). Major complications occurred in 4.8% of cases overall. Univariate analysis showed that both preoperative abscess formation (P=0.048) and increased intraoperative blood loss (P=0.020) were significantly associated with major complications.</p><p><strong>Discussion: </strong>Our findings support that laparoscopic ileocecal resection is both feasible and beneficial for complex CD, offering reduced blood loss and shorter hospital stays. However, both preoperative abscess formation and increased intraoperative blood loss were significantly associated with major complications, highlighting the importance of meticulous infection control and intraoperative hemostasis.</p>","PeriodicalId":56349,"journal":{"name":"Journal of the Anus Rectum and Colon","volume":"9 4","pages":"378-384"},"PeriodicalIF":1.5,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12574806/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145433016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"R0 Resection for Stage IVc Appendiceal Goblet Cell Adenocarcinoma Diagnosed after Left Adnexectomy: A Case Report.","authors":"Naoki Sakuyama, Yasunori Ota, Susumu Aikou, Satoko Momma, Junko Mukohyama, Dai Shida","doi":"10.23922/jarc.2025-025","DOIUrl":"10.23922/jarc.2025-025","url":null,"abstract":"<p><p>The role of surgical resection in stage IV appendiceal goblet cell adenocarcinoma remains unclear. We report a case of a 44-year-old woman who underwent left adnexectomy for an ovarian tumor at another hospital. Pathological examination revealed not only an ovarian mature cystic teratoma but also goblet cell adenocarcinoma in the ovarian stroma, later diagnosed as appendiceal goblet cell adenocarcinoma with ovarian metastasis. Further evaluation suggested tumor invasion or metastasis to the rectosigmoid colon. Given the feasibility of curative resection, laparoscopic surgery was performed. Intraoperative findings confirmed rectal metastasis rather than direct invasion from appendiceal goblet cell adenocarcinoma. Peritoneal seeding to the greater omentum was confirmed intraoperatively, leading to total proctocolectomy with Hartmann's procedure, omentectomy, and right adnexectomy. Macroscopically, R0 resection was achieved. Pathological examination confirmed Grade 1 appendiceal goblet cell adenocarcinoma with metastases to the right ovary, rectosigmoid colon, and peritoneum. The patient received adjuvant chemotherapy and remains recurrence-free at 33 months postoperatively. This case highlights the importance of precise pathological assessment in ovarian tumors and suggests that aggressive surgical management may contribute to long-term survival, even in stage IV appendiceal goblet cell adenocarcinoma.</p>","PeriodicalId":56349,"journal":{"name":"Journal of the Anus Rectum and Colon","volume":"9 4","pages":"458-464"},"PeriodicalIF":1.5,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12574813/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145433047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Operative Time as a Universal Risk Factor for Infectious Complications after Colorectal Cancer Surgery: A Multicenter Stratified Analysis by Surgical Site.","authors":"Takao Shimizu, Takeshi Yamada, Takuya Nishino, Kay Uehara, Akihisa Matsuda, Keisuke Minamimura, Yasuyuki Yokoyama, Ryo Ohta, Nobuhiko Taniai, Hiroshi Yoshida","doi":"10.23922/jarc.2025-046","DOIUrl":"10.23922/jarc.2025-046","url":null,"abstract":"<p><strong>Objectives: </strong>Postoperative infectious complications in colorectal cancer prolong hospital stays and increase the risk of recurrence. Given that risk factors may vary depending on the surgical procedure-namely, right-sided colon, left-sided colon, and rectal cancer-we aimed to identify both common and procedure-specific risk factors．.</p><p><strong>Methods: </strong>This retrospective multicenter study included 2,636 patients who underwent elective colorectal cancer surgery between April 2015 and March 2023 at three affiliated institutions. The primary endpoint was the incidence of Clavien-Dindo grade ≥2 infectious complications by surgical site. Multivariate logistic regression analyses were performed to identify common and procedure-specific risk factors across the three anatomical groups．.</p><p><strong>Results: </strong>Infectious complications occurred in 18.5% of patients. The incidence significantly differed by surgical site: 11.7% in right-sided colon, 14.6% in left-sided colon, and 22.0% in rectal cancer (P < 0.001). Operative time was the only risk factor common to all procedures. Right-sided colon cancer was associated with additional risks including advanced age, low BMI, male sex, and open surgery. Rectal cancer, in contrast, showed younger age and male sex as contributing factors. Both male sex and higher BMI correlated significantly with longer operative times in all groups．.</p><p><strong>Conclusions: </strong>Prolonged operative time appears to be a consistent and independent risk factor for postoperative infectious complications across various colorectal cancer procedures. In contrast, other factors such as age, body mass index, sex, and surgical approach showed associations that varied depending on the type of procedure．.</p>","PeriodicalId":56349,"journal":{"name":"Journal of the Anus Rectum and Colon","volume":"9 4","pages":"420-427"},"PeriodicalIF":1.5,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12574814/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145432954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clinicopathological Features by Differentiation and Prognostic Factors in Anal Canal Carcinoma.","authors":"Hajime Kayano, Seiichiro Yamamoto, Yasumitsu Saiki, Kazutaka Yamada, Kenichi Sugihara, Yoichi Ajioka","doi":"10.23922/jarc.2025-024","DOIUrl":"10.23922/jarc.2025-024","url":null,"abstract":"<p><strong>Objectives: </strong>In this study, we aimed to present the clinicopathological features of anal canal carcinomas based on differentiation and clarify whether differentiation affects prognosis.</p><p><strong>Methods: </strong>We included 597 patients with adenocarcinoma registered in the multicenter colorectal cancer registry data of the Colorectal Cancer Study Group. We also included 151 patients with squamous cell carcinoma enrolled by the 47 medical affiliates of the Colorectal Cancer Study Group in a multicenter cohort study conducted in Japan. The clinicopathological features by differentiation and prognostic factors of each histological type were examined retrospectively.</p><p><strong>Results: </strong>The clinicopathological features of adenocarcinoma were similar to those of rectal carcinoma by differentiation. In contrast, the clinicopathological features of squamous cell carcinoma did not differ according to differentiation. Differentiation was a prognostic factor in patients with adenocarcinoma (G3/4; hazard ratio: 1.91, 95% confidence interval: 1.22-3.01, <i>p</i>=0.0043) but not in patients with squamous cell carcinoma.</p><p><strong>Conclusions: </strong>Differentiation was a prognostic factor for adenocarcinoma in anal canal carcinoma; thus, differentiation should be considered in the treatment strategy. However, differentiation was not a prognostic factor in squamous cell carcinoma. Further studies should explore the involvement of differentiation in squamous cell carcinoma treatment.</p>","PeriodicalId":56349,"journal":{"name":"Journal of the Anus Rectum and Colon","volume":"9 4","pages":"385-397"},"PeriodicalIF":1.5,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12574808/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145432986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}