Colorectal cancer after bariatric surgery (Cric-Abs 2020): Sicob (Italian society of obesity surgery) endorsed national survey

Background The published colorectal cancer (CRC) outcomes after bariatric surgery (BS) are conflicting, with some anecdotal studies reporting increased risks. The present nationwide survey CRIC-ABS 2020 (Colo-Rectal Cancer Incidence-After Bariatric Surgery-2020), endorsed by the Italian Society of Obesity Surgery (SICOB), aims to report its incidence in Italy after BS, comparing the two commonest laparoscopic procedures-Sleeve Gastrectomy (SG) and Roux-en-Y gastric bypass (GBP). Methods Two online questionnaires-first having 11 questions on SG/GBP frequency with a follow-up of 5-10 years, and the second containing 15 questions on CRC incidence and management, were administered to 53 referral bariatric, high volume centers. A standardized incidence ratio (SIR-a ratio of the observed number of cases to the expected number) with 95% confidence intervals (CI) was calculated along with CRC incidence risk computation for baseline characteristics. Results Data for 20,571 patients from 34 (63%) centers between 2010 and 2015 were collected, of which 14,431 had SG (70%) and 6140 GBP (30%). 22 patients (0.10%, mean age = 53 +/- 12 years, 13 males), SG: 12 and GBP: 10, developed CRC after 4.3 +/- 2.3 years. Overall incidence was higher among males for both groups (SG: 0.15% vs 0.05%; GBP: 0.35% vs 0.09%) and the GBP cohort having slightly older patients. The right colon was most affected (n = 13) and SIR categorized/sex had fewer values < 1, except for GBP males (SIR = 1.07). Conclusion Low CRC incidence after BS at 10 years (0.10%), and no difference between procedures was seen, suggesting that BS does not trigger the neoplasm development.