Purpose: A variety of clinical features of anastomotic leak occur during the surgical treatment of rectal cancer. However, little information regarding management of leakage is available and treatment guidelines have not been validated. The aim of this study was to evaluate the validity of currently proposed expert opinions on the management of anastomotic leak, after low anterior resection for rectal cancer. Methods: A retrospective analysis was conducted for 1,786 patients who underwent sphincter-preserving surgery for rectal cancer between 2005 and 2015. Clinical outcomes including anastomotic leak-associated mortality and permanent stoma were analyzed. Results: The overall incidence of anastomotic leak was 6.8% (122 of 1,786), including 6.1% (30 of 493 patients) with diverting stoma and 7.1% (92 of 1,293 patients) without diverting stoma (p = 0.505). A majority of patients without diversion were treated with diverting stoma (76 of 88 patients [86.4%]); 1 mortality (0.8%) was observed in this group. Treatments in the diversion group mainly included conservative treatment, local drainage, and/or transanal repair (26 of 30 patients [86.7%]).The anastomotic failure rates were 20.7% (19 of 92 patients) in the no diversion group and 53.3% (16 of 30 patients) in the diversion group. In the multivariate analysis, preoperative chemoradiotherapy (p < 0.001) and delayed diagnosis of anastomotic leak (p = 0.036) were independent risk factors for permanent stoma. Conclusion Management of anastomotic leak should be tailored to individual patients. When anastomotic leak occurred, preoperative chemoradiotherapy and delayed diagnosis seemed to be associated with permanent stoma.

Purpose: The relationship between microsatellite instability (MSI) and tumor response after neoadjuvant chemoradiotherapy (nCRT) in rectal cancer remains unclear. The present study aimed to evaluate the association between MSI and tumor response to nCRT in rectal cancer treatment. Methods: Patients with rectal cancer from 2 tertiary hospitals who underwent nCRT, followed by radical surgery, were included. The microsatellite status was determined using a PCR-based Bethesda panel. Tumors with a Dworak’s tumor regression grade of 3 or 4 were considered to have a good response. Predictive factors for a good response to nCRT were analyzed. Results: Of the 1,401 patients included, 910 (65.0%) had MSI results and 1.5% (14 of 910) showed MSI-H. Among all the patients, 519 (37.0%) showed a good response to nCRT. A univariate analysis showed that MSI-H tended to be negatively associated with a good response to nCRT, but no statistical significance was observed (7.1% vs. 24.1%, P = 0.208).Multivariate analysis showed that well-differentiated tumors were the only predictive factor for good response to nCRT (odds ratio [OR], 2.241; 95% confidence interval [CI], 1.492–3.364; P < 0.001). MSI status tended to be associated with the response to nCRT (OR, 0.215; 95% CI, 0.027–1.681; P = 0.143). Conclusion MSI-H was not associated with response to nCRT in patients with rectal cancer.

PURPOSE: The bowel frequency of patients who had undergone rectal resection might be difficult to distinguish from the diarrhea of Clostridium difficile infection (CDI). The change of bowel movement following rectal surgery has been a challenge for the diagnosis of CDI and scarce studies discussed this diagnostic difficulty.METHODS: From January 2004 to January 2018, a total of 8,327 patients in a single tertiary colorectal cancer center was evaluated for CDI, and their medical records were ret rospectively reviewed. Bowel frequency and treatment outcomes were compared between the rectal resection group (RG) and colectomy group (CG). Diagnostic time was defined as the time interval between first diarrhea (more than three times a day) and pathologic confirmation date of CDI.RESULTS: CDI incidence was 2.3% (17/752) vs. 0.41% (31/7,575) between RG and CG (P<0.001). RG had frequent bowel movements than CG (RG: 13.56±6.16/day vs. CG: 8.39±6.23/day; P=0.010), but the interval between the time of symptom and the time of CDI diagnosis was longer in the RG than in CG (RG: 1.38±3.34 days vs. CG: 0.39±1.16 days). A total of three mortalities has been occurred (RG: 2 vs. CG: 1), and the reasons were delayed diagnosis and omitted treatment.CONCLUSION: Patients experienced significant bowel frequency after rectal surgery than after colectomy, and the delayed diagnosis was associated with mortality. Active surveillance for CDI should be performed for the patients who underwent rectal surgery to prevent morbidity and mortality from delayed diagnosis of CDI, but sophisticated guideline also should be evaluated to reduce over-examinations.
Clostridium difficile ; Clostridium ; Colectomy ; Colon ; Colorectal Neoplasms ; Colorectal Surgery ; Delayed Diagnosis ; Diagnosis ; Diarrhea ; Humans ; Incidence ; Medical Records ; Mortality ; Rectum ; Treatment Outcome

BACKGROUND/OBJECTIVES: This study aimed to evaluate the effect of preoperative immunonutrition on the composition of fecal microbiota following a colon cancer surgery.MATERIALS/METHODS: This study was a secondary analysis of a randomized controlled trial assessing the impact of preoperative immunonutrition on the postoperative outcomes of colon cancer surgery. Patients with primary colon cancer were enrolled and randomly assigned to receive additional preoperative immunonutrition or a normal diet alone.Oral nutritional supplementation (400 mL/day) with arginine and ω-3 fatty acids were administered to patients in the immunonutrition group for 7 days prior to surgery. Thirtytwo fecal samples were collected from 16 patients in each group, and the composition of fecal microbiota was compared between the 2 groups. RESULTS: At the phylum level, no significant difference was observed in the composition of microbiota between the 2 groups (Firmicutes, 69.1% vs. 67.5%, P = 0.624; Bacteroidetes, 19.3% vs. 18.1%, P = 0.663; Actinobacteria, 6.7% vs. 10.6%, P = 0.080). The Firmicutes/Bacteroidetes ratio (4.43 ± 2.32 vs. 4.55 ± 2.51, P = 0.897) was also similar between the 2 groups. At the genus level, the proportions of beneficial bacteria such as Faecalibacterium spp. (8.1% vs. 6.4%, P = 0.328) and Prevotella spp. (6.9% vs. 4.8%, P = 0.331) were higher, while that of Clostridium spp. was lower (0.5% vs. 1.2%, P = 0.121) in the immunonutrition group, but the difference was not significant. CONCLUSIONS Immunonutrition showed no significant association with the composition of fecal microbiota. The relationship between immunonutrition and the fecal microbiota should be investigated further in large-scale studies.

Purpose: Some studies have suggested that circumferential tumor location (CTL) of rectal cancer may affect oncological outcomes. However, studies after preoperative chemoradiotherapy (CRT) are rare. This study aimed to evaluate the impact of CTL on oncologic outcomes of patients with mid to low rectal cancer who received preoperative CRT. Methods: Patients with mid to low rectal cancer who underwent total mesorectal excision after CRT from January 2013 to December 2018 were included in this retrospective study. The impact of CTL on the pathological circumferential resection margin (CRM) status, local recurrence-free survival (LRFS), disease-free survival (DFS), and overall survival (OS) was analyzed. Results: Of the 381 patients, 98, 70, 127, and 86 patients were categorized into the anterior, posterior, lateral, and circumferential tumor groups, respectively. Tumor location was not significantly associated with the pathological CRM involvement (anterior, 12.2% vs. posterior, 14.3% vs. lateral, 11.0% vs. circumferential, 17.4%; P = 0.232). Univariate analyses revealed no correlation between CTL and 3-year LRFS (93.0% vs. 89.1% vs. 91.5% vs. 88%, P = 0.513), 3-year DFS (70.3% vs. 70.2% vs. 75.3% vs. 75.7%, P = 0.832), and 5-year OS (74.7% vs. 78.0% vs. 83.9% vs. 78.2%, P = 0.204). Multivariate analysis identified low rectal cancer and pathological CRM involvement as independent risk factors for all survival outcomes (all P < 0.05). Conclusion CTL of rectal cancer after preoperative CRT was not significantly associated with the pathological CRM status, recurrence, and survival.