OBJECTIVETo evaluate the association of early diarrhea and fecal volume with anastomotic leakage after low anterior resection (LAR) of rectal cancer.

METHODSClinical data of 541 patients with rectal cancer undergoing LAR at The Affiliated Hospital of Guangdong Medical College between January 2007 and January 2017 were analyzed retrospectively. Early postoperative diarrhea was defined as at least one occurrence of more than 50 ml watery stool or at least four times defecation per day within 7 days after surgery. The volume of fecal discharge from the transanal drain was measured at daily intervals for 3 days after surgery. Association of early diarrhea and anastomotic leakage was analyzed using logistic regression model. The accuracy of fecal volume in predicting anastomotic leakage was evaluated using receiver operating characteristics (ROC) curve.

RESULTSThere were 319 males and 222 females with mean age of 59.3 years. Early postoperative diarrhea occurred in 99(18.3%) patients, and 41(7.6%) patients developed anastomotic leakage. The incidence of anastomodc leakage in patients with early diarrhea was significantly higher as compared to those without early diarrhea (15.2% vs. 5.9%, P=0.000). Multivariate analysis revealed that early diarrhea (OR=33.940, 95%CI: 8.423 to 89.240) and the distance between the tumor and the anal verge less than 7 cm (OR=13.085, 95%CI: 2.117 to 44.556) were independent risk factors for anastomotic leakage, while the presence of a transanal tube was an independent protective factor (OR=0.474, 95%CI: 0.122 to 0.881). The total fecal volume for 3 days after surgery was calculated in 162 patients with a transanal tube. The median fecal volume was 210 (100 to 4360) ml and 60 (0 to 480) ml in patients with and without anastomotic leakage respectively(P=0.000). ROC curve showed that the cut-off value of fecal volume for anastomotic leakage was 110 ml and the area under the curve was 0.824 with a high sensitivity of 85.7% and specificity of 81.3%.

CONCLUSIONSEarly postoperative diarrhea after LAR procedure of rectal cancer may be an early predictor of anastomotic leakage, and fecal volume for 3 days after surgery ≥110 ml can accurately predict anastomotic leakage. Active prevention and management of early postoperative diarrhea may reduce the risk of anastomotic leakage.