Bariatric surgery reduces cancer risk in morbidly obese patients

Background: To assess the effect of bariatric surgery on the cancer risk of patients with morbid obesity because evidence is mounting of an association between obesity and cancer. Methods: We performed an observational 2-cohort study. The treatment cohort (n = 1035) included patients who had undergone bariatric surgery from 1986 to 2002. The control group (n = 5746) included age- and gender-matched morbidly obese patients who had not undergone weight-reduction surgery and who were identified from a single-payor administrative database. The Subjects with physician or hospital visits for a cancer-related diagnosis or treatment within the 6 months previous to the beginning of the Study were excluded. The cohorts were followed up for a maximum of 5 years from study inception. Results: Bariatric surgery resulted in a significant reduction in the mean percentage of excess weight loss (67.1%, P <001). The surgery patients had significantly fewer physician/hospital visits for all cancer diagnoses (n = 21, 2.0%) compared with the controls (n = 487, 8.45%; relative risk .22, 95% confidence interval .143-.347; P =.001). The physician/hospital visits for common cancers such as breast cancer were significantly reduced in the surgery group (P =.001). For all other cancers, the physician/hospital visits showed a trend toward being lower in the surgery group. Because of the low frequencies, statistical significance could not be demonstrated for individual cancer diagnoses. Conclusion: The data suggest that bariatric surgery improves the cancer outcomes in some morbidly obese patients. (Surg Obes Relat Dis 2008;4:691-697.) (C) 2008 American Society for Metabolic and Bariatric Surgery. All rights reserved.