Short-term results in a population based study indicate advantage for minimally invasive rectal cancer surgery versus open

The aim of this study was to determine if minimally invasive surgery (MIS) for rectal cancer is non-inferior to open surgery (OPEN) regarding adequacy of cancer resection in a population based setting. All 9,464 patients diagnosed with rectal cancer 2012-2018 who underwent curative surgery were included from the Swedish Colorectal Cancer Registry. Primary outcomes: Positive circumferential resection margin (CRM <1 mm) and positive resection margin (R1). Non-inferiority margins used were 2.4% and 4%. Secondary outcomes: 30-and 90-day mortality, clinical anastomotic leak, re-operation <30 days, 30-and 90-day re-admission, length of stay (LOS), distal resection margin <1mm and <12 resected lymph nodes. Analyses were performed by intention-to-treat using unweighted and weighted multiple regression analyses. There were no difference in CRM <1 mm or R1 in the adjusted unweighted or weighted analyses. CRM: MIS 3.7% and OPEN 5.4%, risk difference-1.8% (95% CI-2.79%,-0.86%). R1: MIS 2.9% and OPEN 4.6%, risk difference-1.7% (95% CI-2.51%,-0.85%). All analyses demonstrated decreased mortality and re-admissions at 30 and 90 days as well as shorter LOS following MIS. In this population based setting MIS for rectal cancer was non-inferior to OPEN regarding adequacy of cancer resection with favourable short-term outcomes.