[Transanal drainage tube for prevention of anastomotic leak after anterior resection for rectal cancer: a meta-analysis]

Objective: To assess the effectiveness of transanal drainage tube (TDT) in reducing the incidence of anastomotic leak following anterior resection in patients with rectal cancer. Methods: We conducted a systematic search for relevant studies published from inception to October 2022 across multiple databases, including PubMed, Embase, Web of Science, Cochrane Library, CNKI, Wanfang, and VIP. Meta-analysis was performed using Review Manager 5.4 software. The primary outcomes included total incidence of anastomotic leak, grade B and C anastomotic leak rates, reoperation rate, anastomotic bleeding rate, and overall complication rate. Results: Three randomized controlled trials involving 1115 patients (559 patients in the TDT group and 556 in the non-TDT group) were included. Meta-analysis showed that the total incidences of anastomotic leak and of grade B anastomotic leak were 5.5% (31/559) and 4.5% (25/559), respectively, in the TDT group and 7.9% (44/556) and 3.8% (21/556), respectively, in the non-TDT group. These differences are not statistically significant (P=0.120, P=0.560, respectively). Compared with the non-TDT group, the TDT group had a lower incidence of grade C anastomotic leak (1.6% [7/559] vs. 4.5% [25/556]) and reoperation rate (0.9% [5/559] vs. 4.3% [24/556]), but a higher incidence of anastomotic bleeding (8.2% [23/279] vs. 3.6% [10/276]). These differences were statistically significant (P=0.003, P=0.001, P=0.030, respectively). The overall complication rate was 26.5%(74/279) in the TDT group and 27.2% (75/276) in the non-TDT group. These differences are not statistically significant (P=0.860). Conclusions: TDT did not significantly reduce the total incidence of anastomotic leak but may have potential clinical benefits in preventing grade C anastomotic leak. Notably, placement of TDT may increase the anastomotic bleeding rate.