Anorectal transplantation (ART) belongs to the emerging field of vascularized composite allotransplantation. Researchers have studied this procedure experimentally for over two decades as a strategy to restore anal function in patients with severe fecal incontinence and permanent colostomy. These conditions significantly impact the quality of life and pose a global public health issue. This narrative review provides a comprehensive analysis of anorectal transplantation research, covering experimental studies in animal models, and ex vivo investigations. It examines and compares different surgical techniques, considering both procedural effectiveness and functional recovery. These experiments indicate that ART can be successfully performed from a technical standpoint. Ex vivo studies demonstrate acceptable surgical times, and studies in animal models confirm graft viability and functional restoration. Future research should refine surgical techniques, investigate neural regeneration mechanisms, and develop immunosuppressive protocols to advance the field toward clinical application. ART holds the potential to completely change the treatment of severe anorectal dysfunction and permanent colostomy, offering a definitive solution to these irreversible conditions.

Objectives: This study aimed to evaluate short-term outcomes of sacral neuromodulation (SNM) for fecal incontinence (FI) in a Japanese clinical setting, and to assess the predictive value of response during the test stimulation phase.

Methods: We retrospectively evaluated patients with FI who underwent SNM between 2014 and 2024. Patients proceeded to permanent implantation following a 2-week test stimulation. Primary outcomes included changes in weekly FI episodes, Cleveland Clinic Florida Fecal Incontinence Score (CCFIS), Fecal Incontinence Severity Index (FISI), and Japanese Fecal Incontinence Quality of Life Scale (JFIQL). Anorectal manometry data were also assessed. A receiver operating characteristic (ROC) curve was constructed to investigate the predictive utility of test-phase response.

Results: Of 34 patients, 32 (94.1%) proceeded to implantation. Two subsequently required explantation, and 30 completed the 12-month follow-up. At 12 months, median weekly FI episodes decreased from 7.5 to 3.0, CCFIS from 15.0 to 9.0, and FISI from 36.5 to 22.5; JFIQL improved from 2.02 to 2.53 (all p < 0.05). A ≥50% reduction in FI episodes was achieved in 20 of 30 patients (66.7%). Maximum squeezing pressure significantly increased from 90.0 to 107.0 mmHg (p = 0.013), while maximum resting pressure did not change significantly. ROC analysis yielded an area under the curve (AUC) of 0.663, identifying a 36.4% reduction in FI episodes during the test phase.

Conclusions: SNM demonstrated favorable short-term outcomes in Japanese patients with FI, including improved continence, quality of life, and anal sphincter function. Early partial response during the test phase may serve as a useful predictor of sustained benefit.

Objectives: Adjuvant chemotherapy (AC) is the standard treatment for stage III colorectal cancer (CRC). However, its effectiveness is limited owing to adverse effects, particularly chemotherapy-induced peripheral neuropathy (CIPN). The objective of this study was to evaluate the real-world efficacy of Ninjin'yoeito (NYT), a traditional Kampo medicine, in improving chemotherapy tolerance and reducing adverse effects during AC with capecitabine plus oxaliplatin (CAPOX).

Methods: Fifty-eight patients undergoing AC with CAPOX for CRC were retrospectively analyzed. The patients were divided into two groups: those who received NYT (N group) and those who did not receive NYT (C group). Propensity score matching (PSM) was performed to minimize baseline differences. Outcomes, including appetite loss, fatigue, CIPN, and relative dose intensity (RDI), were compared between the groups.

Results: According to the post-matching analysis, the N group demonstrated significant reductions in appetite loss (Grade ≥1:16 vs. 10; p = 0.03), fatigue (Grade ≥1:17 vs. 12; p = 0.04), and CIPN (Grade ≥1:14 vs. 7; p = 0.02). In addition, the N group exhibited significantly higher RDI for capecitabine (93.6% vs. 73.5%; p = 0.002) and oxaliplatin (83.5% vs. 55.8%; p < 0.001). No NYT-related adverse events were observed.

Conclusion: NYT could improve AC outcomes by reducing adverse effects and supporting a higher RDI, particularly in patients with frailty.

Objectives: Robot-assisted surgery has rapidly expanded worldwide. The hinotori™ Surgical System (hinotori), the first domestically developed robotic platform in Japan, has recently been introduced in colorectal surgery. This study aimed to evaluate the clinical outcomes of colorectal procedures performed using the hinotori.

Methods: A single-center retrospective observational study was conducted on consecutive patients who underwent robot-assisted colorectal surgery with the hinotori at Kyoto University Hospital between August 2023 and November 2025. Patient demographics, operative details, and short-term outcomes were analyzed separately for colon and rectal cancer.

Results: A total of 94 patients were included: 53 with colon cancer and 41 with rectal cancer. In the colon cancer group, the median operative time was 255 minutes, and one patient (1.9%) developed a Clavien-Dindo grade II complication; no grade ≥III events occurred. In the rectal cancer group, the median operative time was 327 minutes, and one patient (2.4%) experienced a grade II complication; no grade ≥III complications occurred. No conversions to open surgery and no reoperations within 30 days were observed. The median postoperative hospital stay was 10 days for colon cancer and 12 days for rectal cancer.

Conclusion: Robot-assisted colorectal surgery using the hinotori was safe and feasible. This largest case series to date provides data supporting its feasibility and safety.

Objectives: We aimed to clarify the differences in clinical and histological characteristics between two decompression techniques for obstructive colorectal cancer (OCRC): trans-anal decompression tube (TADT) and self-expandable metallic stent (SEMS).

Methods: Overall, 96 of 175 patients with OCRC treated in our department between 2000 and 2020, were assigned into TADT (n = 44) and SEMS (n = 52) groups, and the success rate and complications of decompression, surgical outcomes, clinicopathological findings, and prognosis were compared.

Results: The technical success rate was high in all patients. During surgery, the SEMS group showed significant differences in laparoscopy (p < 0.01), D3 dissection (p < 0.001), and the number of lymph nodes dissected (p < 0.01). In multivariate analysis, lymphatic invasion was associated with decompression (odds ratio [OR], 5.49; 95% confidence interval [CI], 2.12-14.20; p < 0.01) and lymph node metastasis (OR, 4.44; 95% CI, 1.69-11.70; p < 0.01), while SEMS was associated with venous invasion (OR, 0.40; 95% CI, 0.16-0.98; p = 0.04). The 5-year and recurrence-free survival rates for 70 patients with stage II and III OCRC were 76.7% and 73.2%, respectively. Although there was no significant difference in the overall survival, the recurrence-free survival was significantly better in the SEMS group (85.0% vs. 58.3%, p = 0.04).

Conclusions: The results of this study suggest that SEMS may be preferable to TADT from a histological perspective.

Objectives: This study aims to evaluate the short-term surgical outcomes and clarify the risk factors of mortality and morbidity within the 90 days following palliative surgery for malignant bowel obstruction (MBO) caused by unresectable colorectal cancer (CRC) from an immuno-nutritional point of view.

Methods: 66 patients had palliative surgery for MBO caused by unresectable CRC due to metastatic and recurrent tumors between January 2005 and December 2021. We evaluated 57 patients, excluding nine due to missing data. In a multivariate analysis, clinically relevant variables, including age, American Society of Anesthesiologists Physical Status Classification, Controlling Nutritional Status (CONUT) score, Prognostic Nutrition Index (PNI), and perioperative factors, were evaluated as potential risk factors.

Results: Three (5.3%) patients died within 30 days. Clavien-Dindo classification grade (C-D) ≥3 complications occurred in 10 (17.5%) patients. Although all patients required stoma creation, they resumed oral intake in 3 postoperative days (range, 1-9). The median overall survival was 224 days, with a 90-day mortality rate of 24.6%. In the multivariable analyses, a higher preoperative CONUT score was significantly associated with 90-day mortality. In addition, both a higher CONUT score and emergency surgery were significantly associated with the occurrence of C-D grade ≥3 complications.

Conclusions: A higher preoperative CONUT score may provide valuable prognostic information regarding short-term outcomes, including 90-day mortality and severe postoperative complications, following palliative surgery for MBO caused by unresectable colorectal cancer.

Objectives: Preoperative chemotherapy increases resectability in patients with resectable colorectal liver metastasis who undergo curative hepatectomy; however, there is no consensus regarding patient selection. The aim of this study was to identify high-risk patients with synchronous colorectal liver metastasis and compare the outcomes of preoperative chemotherapy with those of upfront surgery.

Methods: This multi-institutional, retrospective study enrolled patients who underwent their first liver resection for synchronous colorectal liver metastasis from January 2010 to July 2019. We retrospectively studied the clinicopathological features and prognoses of synchronous colorectal liver metastasis subjected to curative liver resection. Surgical outcomes were compared between the preoperative chemotherapy and upfront surgery groups.

Results: We analyzed 215 patients categorized into the preoperative chemotherapy (n=111) and upfront surgery (n=104) groups. The distribution of primary colorectal cancer locations significantly differed, and the preoperative chemotherapy group had more and larger tumors than did the upfront surgery group. There were no significant between-group differences in recurrence-free survival and overall survival. Primary lymph node metastasis ≥N2, tumor burden score >5, positive carbohydrate antigen 19-9 on treatment, and the Kirsten rat sarcoma viral oncogene homolog mutation were independent risk factors for recurrence-free survival. The recurrence-free survival rate was significantly higher in the preoperative chemotheapy group than in the upfront surgery group for patients with ≥2 risk factors.

Conclusions: Our study suggests new criteria for identifying high-risk patients with synchronous colorectal liver metastasis and shows that preoperative chemotherapy may be an effective option for high-risk patients with ≥2 risk factors.

Objectives: Postoperative clinical recurrence is common in patients with Crohn's disease (CD) despite intestinal resection. Although histopathological findings at resection margins suggestively influence recurrence, their prognostic value remains unclear. This study evaluated the pathological features of the intestinal resection margins in CD and assess their utility in predicting postoperative clinical recurrence.

Methods: This retrospective, single-centre cohort study included 224 patients with CD who underwent intestinal resection without visible residual disease at the Tokyo Yamate Medical Center between January 2019 and December 2021. The patients were followed up until July 2024. The histological features at the resection margins, including plexitis, positive margins, granulomas, and lymphoid follicles, were graded using standardised systems. Associations between these histopathological findings, preoperative clinical characteristics, and clinical recurrence were analysed using univariate and multivariate methods; survival analyses used the Kaplan-Meier method and Cox proportional hazards models.

Results: Severe plexitis at the proximal margin was found in 60.3% of cases and was not associated with preoperative clinical factors or distance from macroscopic lesions. Cox regression identified severe plexitis (hazard ratio [HR]: 1.64, 95% confidence interval [CI]: 1.11-2.44, p=0.013) and lack of prophylactic treatment (HR: 1.64, 95% CI: 1.14-2.35, p=0.007) as independent predictors of clinical recurrence. A stepwise relationship was observed between plexitis severity and recurrence risk.

Conclusions: Severe plexitis at the proximal margin is an independent histopathological predictor of CD postoperative clinical recurrence and is unaffected by preoperative factors or resection length, serving as an objective and valuable marker for postoperative risk stratification.

Objectives: Optimal indications for lateral lymph node dissection in patients with rectal cancer have not yet been established. To address this, we previously proposed magnetic resonance imaging-based size criteria that combine long- and short-axis measurements. However, the initial study derived criteria based on an analysis with knowledge of histopathological outcomes. Therefore, this study aimed to prospectively validate the clinical utility of these magnetic resonance imaging-based criteria.

Methods: We conducted a prospective multicenter validation study including 125 patients with rectal cancer who underwent radical surgery with lateral lymph node dissection. Two independent reviewers who were blinded to the clinical and pathological data evaluated 250 lateral pelvic regions using pretreatment magnetic resonance imaging. Interobserver agreement was assessed using weighted kappa statistics. The need for lateral lymph node dissection was evaluated using predefined size-based criteria and compared with the histopathological outcomes.

Results: Among the 250 lateral regions evaluated, 206 were dissected, and 29 were histopathologically positive for lateral lymph node metastases. Two reviewers independently assessed whether lateral lymph node dissection was required or could be omitted in 250 regions based on the criteria, and the interobserver agreement was good (weighted kappa = 0.671). The proposed criteria achieved sensitivities of 86.2% and 82.8% and specificities of 57.1% and 52.0% for reviewers 1 and 2, respectively.

Conclusion: This validation study demonstrated that our magnetic resonance imaging-based size criteria are clinically applicable and effective for the preoperative diagnosis of lateral lymph node metastases.

Objectives: Familial adenomatous polyposis (FAP) is an inherited disorder characterized by multiple colorectal polyposis and is frequently associated with a variety of extracolonic lesions. However, neoplastic lesions of the biliary tract system, excluding those of the ampulla of Vater, are extremely rare in FAP, and the impact of APC alterations on their tumorigenesis remains unclear. We aimed to clarify the relationship between germline variants and somatic variants in the APC gene in biliary tract neoplasms (BTNs) of FAP patients.

Methods: A total of 115 genetically confirmed FAP cases treated at our department between 1997 and 2024 were investigated regarding development of BTNs. APC gene analysis was performed in the BTNs.

Results: Of 115 FAP cases, three developed BTNs. Case 1 was a 69-year-old female who underwent subtotal stomach-preserving pancreaticoduodenectomy for duodenal and middle bile duct carcinoma. Case 2 was a 67-year-old female who underwent pancreaticoduodenectomy for gastric, duodenal, and upper bile duct carcinoma. Case 3 was a 47-year-old male who underwent pancreas-sparing total duodenectomy with cholecystectomy for Spigelman Stage IV duodenal polyposis and gallbladder polyposis. In addition to germline pathogenic variants, somatic pathogenic variants of APC were identified in all the BTNs.

Conclusions: These findings suggest that the APC two-hit theory may underlie the tumorigenesis of these rare BTNs, consistent with the pathogenic process observed in colonic and other extracolonic lesions in patients with FAP.

Purpose: This study evaluated the concordance between preoperative clinical and postoperative pathological staging in stage II-III colorectal cancer (CRC), stratified by BRAF V600E mutation and mismatch repair (MMR) status.

Methods: We retrospectively analyzed 754 patients who underwent curative resection for stage II-III CRC between 2015 and 2023. Molecular subtypes were defined as proficient MMR with BRAF mutation (pMMR/BRAF-MT), proficient MMR without mutation (pMMR/BRAF-WT), or deficient MMR (dMMR). Concordance of T factor, N factor, and overall stage was classified as underdiagnosis, match, or overdiagnosis.

Results: The cohort included 29 (3.8%) pMMR/BRAF-MT, 646 (85.7%) pMMR/BRAF-WT, and 79 (10.5%) dMMR cases. The overall concordance rates between clinical and pathological staging were 55.2% for the T factor, 39.9% for the N factor, and 50.4% for stage. N-factor concordance was lowest (39.9%), with pMMR/BRAF-MT showing the highest underdiagnosis (44.8%) and dMMR the highest overdiagnosis (50.6%). Multivariable analysis identified pMMR/BRAF-MT as an independent predictor of N-factor underestimation (OR 2.76, 95% CI 1.24-6.12, p=0.013). Survival analyses were exploratory and potentially underpowered because of the limited number of events.

Conclusions: Molecular subtype significantly affects staging accuracy in stage II-III CRC. BRAF-mutated and dMMR tumors are prone to under- and overstaging, respectively. These findings highlight the potential value of incorporating molecular subtype information into preoperative assessment to improve staging accuracy and guide optimal treatment planning.

Objectives: Colonic self-expandable metallic stents (SEMSs) are widely used for preoperative decompression in obstructive colorectal cancer (CRC) patients undergoing total colonoscopy (TCS). However, the factors influencing the success of TCS and the risk of perforation remain unclear. This study aimed to identify key determinants of successful TCS after SEMS placement.

Methods: We retrospectively analyzed the clinical data of 48 patients who underwent placement of an 18 mm diameter colorectal SEMS as a bridge to surgery (BTS) at a single center between November 2017 and November 2023. Clinical success was defined as successful TCS regardless of endoscopist or scope change. Patients were divided into successful and unsuccessful TCS groups. The effects of tumor (location, stenosis, depth, and peritoneal dissemination) and procedural variables (timing of TCS, stent size, colonoscope type, and performing endoscopist) were analyzed.

Results: The mean patient age was 72 years, and 71% were male. The clinical success rate of TCS was 77% (37/48). Univariate analysis revealed that tumor invasion depth (T4) was significantly associated with TCS failure (odds ratio [OR]: 0.23, P=0.0427). Smaller-diameter colonoscopes were correlated with higher success rates. Synchronous cancers were detected in 10% of the cases.

Conclusions: The tumor invasion depth impacts the success of TCS. Smaller-diameter scopes may improve outcomes, particularly with deeper tumor invasion.

We herein report a rare case of granulocyte colony-stimulating factor (G-CSF) -producing adenosquamous carcinoma of the ascending colon. An 80-year-old man was admitted to our hospital complaining of constipation and hypophagia. His medical history over the past nine years included chronic obstructive pulmonary disease, arteriosclerosis obliterans, and acute limb ischemia. He had no history of inflammatory bowel disease or other gastrointestinal conditions. Colonoscopy and contrast-enhanced computed tomography revealed a tumor in the ascending colon. Biopsies were obtained from five different areas of the lesion, all of which showed histological features consistent with squamous cell carcinoma. Notably, despite the absence of clinical signs of infection, the white blood cell count (WBC) and C-reactive protein (CRP) levels were elevated. Given these findings, a G-CSF-producing tumor was suspected. Subsequent measurement of serum G-CSF levels confirmed this elevation. Based on these findings, we initially suspected G-CSF-producing squamous cell carcinoma of the ascending colon, and proceeded with radical surgical resection. However, the final pathological examination revealed that the tumor contained a minor adenocarcinomatous component (approximately 1%), leading to a definitive diagnosis of adenosquamous carcinoma. We herein review the relevant literature and describe the diagnostic considerations, surgical management, and postoperative course of this rare case.

Background: The da Vinci single port (SP) system is a novel robotic surgical platform that allows multiple robotic instruments and a flexible camera to be introduced through a single umbilical incision. Compared with conventional multi-port robotic or laparoscopic approaches, it offers cosmetic advantages, reduced abdominal wall trauma, and potentially less postoperative pain. These features make it especially suitable for technically demanding gastrointestinal procedures, including simultaneous resections for synchronous malignancies.

Case Presentation: An 81-year-old woman was referred with lower rectal cancer, staged as cT3N0M0 (Stage IIA). Preoperative investigations also identified a synchronous gastric cancer, staged as cT2N0M0 (Stage I). To minimize incision size and surgical invasiveness, the SP system was selected. A distal gastrectomy and low anterior resection were successfully performed in a single session through a single umbilical incision, supplemented by three additional ports, two of which were later used for drain placement. The operation was accomplished without intraoperative difficulties, and the patient recovered smoothly, being discharged without postoperative morbidity.

Conclusion: This case highlights the feasibility and safety of the SP system in simultaneous multi-organ resections for synchronous gastrointestinal cancers. The approach provides an advanced minimally invasive option that minimizes surgical trauma while maintaining oncologic adequacy.