Prophylactic transanal drainage tubes placement for preventing anastomotic leakage after anterior resection for rectal cancer: a meta-analysis.

AIM: To evaluate the efficacy of transanal drainage tube (TDT) placement for preventing anastomotic leakage after low anterior resection for rectal cancer. METHOD: PubMed, the Cochrane Central Register of Controlled Trials, Embase and ClinicalTrials.gov databases were searched up to October 2021. Studies comparing outcomes following low anterior resection with or without transanal drainage tube were included. The primary outcomes measured were anastomotic leakage rate, reoperation rate and anastomotic bleed rate. RESULTS: 3 RCTs and 16 observational studies (prospective or retrospective) involving 4560 patients satisfied the basic inclusion criteria. In RCTs, TDT was associated with no statistically significant differences in anastomotic leakage (OR=0.67 [95% CI: 0.42-1.05, P=0.08), with reduction in reoperation (OR=0.11, 95% CI 0.03-0.51, P=0.004) and increased anastomotic bleeding rate (OR = 2.36, 95% CI: 1.11-5.01, p=0.03). In observational studies, TDT was associated with significant reduction in anastomotic leak (OR = 0.44, 95% CI: 0.30-0.64, p<0.0001) and reoperation (OR = 0.47, 95% CI 0.33-0.69, P<0.0001), with no statistically significant differences in anastomotic bleeding (OR = 1.30, 95% CI: 0.20-8.30, p=0.78). CONCLUSION: In RCTs, TDT for rectal cancer was correlated with no detectable differences in anastomotic leakage and with an increased risk of anastomotic bleeding. In observational studies, TDT was correlated with reduction in anastomotic leakage, and no detectable differences in anastomotic bleeding. Both RCTs and observational studies demonstrated a comparable reduction in reoperation rate with TDT. These data in aggregate indicated that TDTs may not show the superiority but emphasized differences between RCT and observational data.