Weight Loss After Bariatric Surgery Is Associated with Better Cancer Outcomes

Obesity is associated with excess incidence of certain types of cancer and cancer-related mortality. In this retrospective cohort study, researchers used data from a large healthcare system to compare cancer incidence and mortality between 5000 patients with obesity who underwent bariatric surgery and 25,000 similar patients who did not. Patients with histories of cancer, alcohol use disorder, or severe organ damage were excluded from both cohorts.

During median follow-up of 6 years, the incidence rate of 13 obesity-associated cancers (e.g., esophageal adenocarcinoma, renal cell carcinoma, postmenopausal breast cancer, colon cancer, pancreatic cancer) was 3.0 per 1000 person-years in the surgical group versus 4.6 per 1000 person-years in the nonsurgical group. A similar analysis for cancer-related mortality yielded rates of 0.6 vs. 1.2 per 1000 person-years. These differences were statistically significant after adjustment for numerous potential confounding variables. A secondary analysis showed a dose-dependent relation between greater weight loss in the surgery group and lower cancer incidence.