AbstractBackgroundThe aim of this study was to compare the pathological and perioperative outcomes of extracorporealversusintracorporeal anastomosis after laparoscopic transverse colon cancer resection.MethodsIn this retrospective study, patients from seven institutions in China who underwent laparoscopic resection of transverse colon cancer between 2019 and 2021 were selected and included. Either extended right hemicolectomy or transverse colectomy/extended left hemicolectomy was performed. The clinical characteristics and the pathological and perioperative outcomes were compared between patients undergoing extracorporeal or intracorporeal anastomosis. Resection margin lengths were measured on formalin-fixed specimens and an inadequate margin was defined as less than 4.2 cm between the division and the tumour. The outcome of interest was the prevalence of specimens with an inadequate margin. Length of incision, bowel function recovery, hospital stay, early postoperative pain (first day after surgery), 30-day complications, and nodal harvest were investigated as secondary outcomes.ResultsOf 411 patients treated during the study interval, 370 patients with transverse colon cancer were included (23.2 per cent treated with intracorporeal anastomosis and 76.8 per cent treated with extracorporeal anastomosis). The prevalence of specimens with inadequate margins was lower in the intracorporeal anastomosis group compared with the extracorporeal anastomosis group in patients undergoing extended right hemicolectomy (P= 0.045) and in patients undergoing transverse colectomy/extended left hemicolectomy (P= 0.030). In multivariate analysis, extracorporeal anastomosis (OR 2.94 (95 per cent c.i. 1.33 to 6.49),P= 0.008) and transverse colectomy/extended left hemicolectomy (OR 1.75 (95 per cent c.i. 1.03 to 2.96),P= 0.038) were independent risk factors for specimens with an inadequate margin. Intracorporeal anastomosis was associated with a shorter incision length (P< 0.001), an earlier recovery of bowel function (P= 0.035), a shorter postoperative hospital stay (P= 0.042), less early postoperative pain (P< 0.001), a longer specimen length (P= 0.042), a longer resection margin (P= 0.007), and a greater lymph node harvest (P= 0.036). There was no statistically significant difference in 30-day complications.ConclusionPatients with transverse colon cancer have better perioperative outcomes, fewer margins of less than 4.2 cm, and larger lymph node harvests when the anastomosis is performed intracorporeally. Further studies are needed to confirm these findings.Registration numberNCT05061199 (www.clinicaltrials.gov).