Development of cancer after bariatric surgery

Background Although bariatric surgery has been associated with a reduction in risk of obesity-related cancer, data on the effect of bariatric interventions on other cancers are limited. Objectives This study aimed to examine the relationship between bariatric interventions and the incidence of various cancers after bariatric surgery. Setting Administrative statewide database. Methods The New York Statewide Planning and Research Cooperative System database was used to identify all adult patients diagnosed with obesity between 2006 and 2012 and patients who underwent bariatric procedures without preexisting cancer diagnosis and alcohol or tobacco use. Subsequent cancer diagnoses were captured up to 2016. Multivariable proportional subdistribution hazard regression analysis was performed to compare the risk of having cancer among obese patients with and without bariatric interventions. Results We identified 71,000 patients who underwent bariatric surgery and 323,197 patients without a bariatric intervention. Patients undergoing bariatric surgery were less likely to develop both obesity-related cancer (hazard ratio.91; 95% confidence interval, .85–.98; P = .013) and other cancers (hazard ratio .81; 95% confidence interval, .74–.89; P < .0001). Patients undergoing Roux-en-Y gastric bypass had a lower risk of developing cancers that are considered nonobesity related (hazard ratio .59; 95% confidence interval, .42–.83; P = .0029) compared with laparoscopic sleeve gastrectomy. Conclusions Bariatric surgery is associated with a decreased risk of obesity-related cancers. More significantly, we demonstrated the relationship between bariatric surgery and the reduction of the risk of some previously designated nonobesity-related cancers, as well. Reclassification of nonobesity-related cancers and expansion of bariatric indications for reducing the risk of cancer may be warranted.