[Risk factors of anastomotic leakage after anterior resection for rectal cancer and the diagnostic value of computed tomography signs in anastomotic leakage].

OBJECTIVE: To investigate the risk factors and computed tomography (CT) diagnostic accuracy of anastomotic leakage after resection of rectal cancer (Dixon).

METHODS: This retrospective study was conducted in Peking University First Hospital from January 2013 to June 2015. A cohort of 452 patients with rectal cancer was enrolled in the study. All the patients underwent anterior resection. The relationship between clinical-pathological data (including sex, age, body mass index (BMI), presence of diabetes, hypohemoglobin (Hb<90 g/L), hypoalbuminemia (Alb<35 g/L), the distance from the lower edge of the tumors to the anus, tumor diameter, tumor differentiation, tumor TNM stage, neoadjuvant therapy status, ligation of the left colonic artery(LCA), preventive colostomy, and anastomotic leakage was analyzed retrospectively. Univariate analysis using χ2 test and multivariate analysis by using the Ordered Classification Arguments Logistic regression model.

RESULTS: Of all the cases, 281 and 171 patients were men and women, respectively. The median age was 64 years (range, 18-88 years). Forty-seven patients (10.4%) were diagnosed with anastomotic leakage, and the median diagnostic time of anastomotic leakage was 6.5 days(range, 3-31 days). One patient with anastomotic leakage died because of respiratory failure within 1 month postoperatively; 11 patients underwent salvage colostomy performed 2-34 days (median, 7 days) after the first surgery. All the 11 patients underwent colostomy closure within 2 years. The other 35 patients recovered by antibiotic and peritoneal lavage treatment. The mean length of postoperative hospital stay in patients without anastomotic leakage was 8.4±2.4 days, which was significantly shorter than that in patients with anastomotic leakage (34.6±15.7 days), and the difference was statistically significant (t=24.127, P=0.008). The results of the univariate analysis showed that BMI≥28 kg/m2 (χ2 =7.550, P=0.000), diabetes mellitus (χ2 =5.055, P=0.025), Hb<90 g/L preoperatively (χ2 =5.718, P=0.017), Alb<35 g/L preoperatively (χ2 =8.096, P=0.004), distance of <6 cm from the lower edge of the tumors to the anus (χ2 =8.205, P=0.004) and LCA ligation (χ2 =16.540, P=0.000) were risk factors for the occurrence of anastomotic leakage. Multivariate analysis showed that BMI≥28 kg/m2 (OR=1.758, 95%CI: 1.265-2.454, P=0.021), distance of <6 cm from the lower edge of the tumors to the anus (OR=1.530, 95%CI: 1.035-2.117, P=0.037), LCA ligation (OR=1.551, 95%CI: 1.035-2.131, P=0.042) were independent risk factors for anastomotic leakage. The CT diagnostic sensitivity of anastomotic leakage was 91.2%(31/34). The false positive rate of CT for diagnosing anastomotic leakage was zero 7 days after the Dixon procedure.

CONCLUSION: Important factors, including BMI of patients, LCA ligation, and the distance from the lower edge of the tumors to the anus are related with anastomotic leakage. The individual treatments should be considered based on the patient's clinical condition. CT was recommended 7 days postoperatively when anastomotic leakage was highly suspected.