Multicenter analysis of risk factors for anastomotic leakage after middle and low rectal cancer resection without diverting stoma: a retrospective study of 319 consecutive patients.

PURPOSE: The purpose of this study was to evaluate the risk factors for anastomotic leakage (AL) after anterior resection for middle and low rectal cancer in order to help surgeons to decide which patients could benefit from a diverting stoma.

METHODS: Data on 319 patients having a middle and low rectal cancer resection with anastomosis between May 2011 and October 2015 from two hospitals were included in the study. The analysis included the following variables: patient-related variables (gender, age, diabetes mellitus, ASA score, preoperative radiochemotherapy, body mass index, blood hemoglobin, and serum albumin level), tumor-related variables (K-ras status, distance of tumor from the anal verge, histopathologic grade, pathological T stage, pathological N stage, pathological M stage, TNM stage, and tumor size), and surgery-related variables (laparoscopic or open surgery, blood loss, and operative time). Univariate and multivariate regression analysis were carried out to identify risk factors for AL.

RESULTS: The AL rate was 11.91% (38/319). Male (OR 2.898, 95% CI 1.265-6.637, p = 0.012), diabetes mellitus (OR 2.482, 95% CI 1.004-6.134, p = 0.049), K-ras mutation (OR 2.544, 95% CI 1.210-5.348, p = 0.014), distance of tumor from the anal verge (OR 3.445, 95% CI 1.631-7.279, p = 0.001), and preoperative radiochemotherapy (OR 2.790, 95% CI 1.056-7.372, p = 0.039) were independent risk factors of AL. One (2.63%) in 38 patients with AL presented with no risk factor of AL, 6 (15.8%) in 38 patients with 1 risk factor, 16 (42.1%) in 38 patients with 2 risk factors, 9 (23.7%) in 38 patients with 3 risk factors, and 6 (15.7%) in 38 patients with 4 risk factors. No patient with 5 risk factors in our study. AL rate increased with the elevated number of risk factors clustering in individuals.

CONCLUSIONS: K-ras mutation is first reported to be an independent risk factor for AL after sphincter-preserving surgery without diverting stoma. A diverting stoma should be performed in sphincter-preserving surgery for middle and low rectal cancer patients with 2 or more risk factors identified in this analysis.