Comparison of complications and bowel function among different reconstruction techniques after low anterior resection for rectal cancer: a systematic review and network meta-analysis

BACKGROUND: Anastomosis for gastrointestinal reconstruction has been contentious after low anterior resection of rectal cancer for the past 30 years. Despite the abundance of randomized controlled trials (RCTs) on colon J-pouch (CJP), straight colorectal anastomosis (SCA), transverse coloplast (TCP), and side-to-end anastomosis (SEA), most studies are small and lack reliable clinical evidence. We conducted a systematic review and network meta-analysis to evaluate the effects of the four anastomoses on postoperative complications, bowel function, and quality of life in rectal cancer. METHODS: We assessed the safety and efficacy of CJP, SCA, TCP, and SEA in adult patients with rectal cancer after surgery by searching the Cochrane Library, Embase, and PubMed databases to collect RCTs from the date of establishment to May 20, 2022. Anastomotic leakage and defecation frequency were the main outcome indicators. We pooled data through a random effects model in a Bayesian framework and assessed model inconsistency using the deviance information criterion (DIC) and node-splitting method and inter-study heterogeneity using the I-squared statistics (I(2)). The interventions were ranked according to the surface under the cumulative ranking curve (SUCRA) to compare each outcome indicator. RESULTS: Of the 474 studies initially evaluated, 29 were eligible RCTs comprising 2631 patients. Among the four anastomoses, the SEA group had the lowest incidence of anastomotic leakage, ranking first (SUCRA(SEA) = 0.982), followed by the CJP group (SUCRA(CJP) = 0.628). The defecation frequency in the SEA group was comparable to those in the CJP and TCP groups at 3, 6, 12, and 24 months postoperatively. In comparison, the defecation frequency in the SCA group 12 months after surgery all ranked fourth. No statistically significant differences were found among the four anastomoses in terms of anastomotic stricture, reoperation, postoperative mortality within 30 days, fecal urgency, incomplete defecation, use of antidiarrheal medication, or quality of life. CONCLUSIONS: This study demonstrated that SEA had the lowest risk of complications, comparable bowel function, and quality of life compared to the CJP and TCP, but further research is required to determine its long-term consequences. Furthermore, we should be aware that SCA is associated with a high defecation frequency. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12957-023-02977-z.