Long‐term oncological outcomes for minimally invasive surgery versus open surgery for colon cancer—a population‐based nationwide study with a non‐inferiority design

The study aimed to compare 5-year overall survival in a national cohort of patients undergoing curative abdominal resection for colon cancer by minimally invasive surgery (MIS) or by the open (OPEN) technique.All patients diagnosed between 2010 and 2016 in Sweden with pathological Union International Contre le Cancer Stages I-III colon cancer localized in the caecum, ascending colon, hepatic flexure or sigmoid colon and those who underwent curative right sided hemicolectomy, sigmoid resection or high anterior resection by MIS or OPEN were included. Patients were identified in the Swedish Colorectal Cancer Registry from which all data were retrieved. The analyses were performed as intention-to-treat and the relationship between surgical technique (MIS or OPEN) and overall mortality within 5 years was analysed. For the primary research question a non-inferiority hypothesis was assumed with a statistical power of 90%, a one-side type I error of 2.5% and a non-inferiority margin of 2%. For the secondary analyses, multilevel survival regression models with the patients matched by propensity scores were employed, adjusted for patient- and tumour-related variables.A total of 11 605 pathological Union International Contre le Cancer Stages I-III patients were included with 3297 MIS (28.4%) and 8308 OPEN (71.6%) and were followed until 31 December 2020. The primary analysis demonstrated superiority for MIS compared to OPEN. The multilevel survival regression analyses confirmed that 5-year overall survival was higher in MIS with a hazard ratio of 0.874 (95% confidence interval 0.791-0.965), and if excluding pT4 the outcome was similar, with a hazard ratio of 0.847 (95% confidence interval 0.756-0.948).This observational study demonstrated that MIS was favourable to OPEN with regard to 5-year overall survival. These results support the use of laparoscopic colon cancer surgery in routine practice.