Bariatric surgery reduces cancer risk in morbidly obese patients

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.

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.

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.

The data suggest that bariatric surgery improves the cancer outcomes in some morbidly obese patients.