Transanal tube versus defunctioning stoma after low anterior resection for rectal cancer: network meta- analysis of randomized controlled trials Marcus Yeow 1 , Shauna Soh 1 , Joel Wong 1 , Frederick H. Koh 2 , Nicholas Syn 1 , Nicola S. Fearnhead 3 , James Wheeler 3 , R. Justin Davies 3 , Choon Seng Chong 1,4 and Constantinos Simillis 3, * 1 Yong Loo Lin School of Medicine, National University of Singapore, Singapore 2 Colorectal Service, Department of General Surgery, Division of Surgery, Sengkang General Hospital, SingHealth Services, Singapore 3 Cambridge Colorectal Unit, Addenbrookes Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK 4 Division of Colorectal Surgery, Department of Surgery, University Surgical Cluster, National University Hospital, Singapore *Correspondence to: Constantinos Simillis, Cambridge Colorectal Unit, Addenbrookes Hospital, Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge CB2 0QQ, UK (e-mail: constantinos.simillis@addenbrookes.nhs.uk) Introduction Anastomotic leakage (AL), one of the feared complications after low anterior resection (LAR), has been reported to be as high as 20 per cent for LAR 1 . AL may result in poorer oncological outcomes and increased mortality 2 . As such, several methods have been explored to minimize the risk of AL in patients undergoing LAR for rectal cancer, principally by diverting the flow of faeces or by reducing the intraluminal pressure of the bowel 3,4 . Diverting stoma (DS) is one of the widely used methods. However, it is not without its disadvantages; stoma-related complications, poorer quality of life, increased cost, need for reoperation, and more frequent hospitalizations 5 . To avoid the drawbacks of DS, there has been relatively long-standing interest within the surgical community in the use of a transanal tube (TT) to reduce intraluminal pressure, as well as faecal diversion, resulting in a protective effect on anastomotic healing. Although there have been isolated reports of rectal perforation 6 , TT placement is a generally safe procedure in experienced hands. More common disadvantages of TT placement include perianal excoriations and early dislodgement 7 . The aim of this study was to undertake a systematic review and network meta-analysis of randomized controlled trials (RCTs) to compare the different strategies in preventing AL in patients undergoing LAR for rectal cancer. Methods The PubMed, EMBASE, and Cochrane databases were searched from inception to 16 October 2021 for RCTs comparing no intervention (NI), DS, or TT after LAR for rectal cancer. Outcomes of interest were AL and reoperation due to AL. Sensitivity analysis was conducted by excluding trials that included patients with concurrent DS and TT. Detailed methods can be found in the supplementary material. Results A total of 13 RCTs comprising 2277 patients were included in the qualitative and quantitative synthesis (Fig. S1) 3,8–18 . A total of 487 patients were in the DS group, 1092 patients in the NI group, and 698 patients in the TT group (Table 1). Three comparison groups (DS, NI, and TT) were included in all the assessed outcomes (Fig. S2). Overall, seven studies were assessed to be at low risk of bias, two were assessed to have some concerns of bias, and four were assessed to be at high risk of bias (Fig. S3). There was no publication bias found for the outcome of AL in both the overall analysis (P = 0.254) and the sensitivity analysis (P = 0.501), but some evidence of publication bias was found for the outcome of reoperation in the main analysis (P = 0.030; Fig. S4). AL was reported in 13 RCTs (2277 patients) 3,8–19 . In the interval plot (Fig. 1a), NI was associated with higher odds of AL than DS (odds ratio (OR) 3.20, 95 per cent confidence interval (c.i.) 1.92 to 5.33; P , 0.001). TT was associated with higher odds of AL than DS (OR 2.67, 95 per cent c.i. 1.35 to 5.28; P = 0.005). There was no statistical difference in AL between TT and NI (OR 0.84, 95 per cent c.i. 0.51 to 1.36; P = 0.465). Ranking probability based on surface under the cumulative ranking curve (SUCRA) values indicated that DS had the lowest probability of AL (SUCRA = 0.999), followed by TT (SUCRA = 0.386) and NI (SUCRA = 0.115; Table S1). Reoperation due to AL was reported in 10 studies (2005 patients) 3,8–13,15,17,19 . In the interval plot (Fig. 1b), NI was associated with higher odds of reoperation than DS (OR 12.24, 95 per cent c.i. 4.83 to 30.98; P , 0.001). TT was associated with higher odds of reoperation than DS (OR 3.66, 95 per cent c.i. 1.15 to 11.67, P = 0.028). TT was associated with lower odds of reoperation than NI (OR 0.30, 95 per cent c.i. 0.13 to 0.69; P = 0.005). Ranking probability based on SUCRA values indicated that DS had the lowest probability of reoperation (SUCRA = 0.992), followed by TT (SUCRA = 0.507) and NI (SUCRA = 0.001; Table S1). Three RCTs were excluded from the sensitivity analysis 16,18,19 . The main differences in the overall analysis were that TT was associated with a lower odds of AL than NI (OR 0.39, 95 per cent c.i. 0.18 to 0.85 (P = 0.018); Fig. 1c); no statistical difference in AL and reoperation between TT and DS was found (OR 1.32, 95 per cent c.i. 0.56 to 3.11 (P = 0.526; Fig. 1c); and OR 1.86, 95 per cent Received: January 07, 2022. Revised: April 10, 2022. Accepted: May 01, 2022 © The Author(s) 2022. Published by Oxford University Press on behalf of BJS Society Ltd. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com BJS, 2022, 1–4 https://doi.org/10.1093/bjs/znac170 Short Report Downloaded from https://academic.oup.com/bjs/advance-article/doi/10.1093/bjs/znac170/6594873 by guest on 05 June 2022