Bariatric surgery in breast and endometrial cancer patients in California: Population-based prevalence and survival

Abstract Background The number of bariatric surgeries performed in the United States has increased substantially since the 1990’s. However, the prevalence and prognostic impact of bariatric surgery, or weight-loss surgery (WLS), among cancer patients are not known. Objectives We investigated the population-based prevalence of WLS in women with breast or endometrial cancer and conducted exploratory analysis to examine whether post-diagnosis WLS is associated with survival. Setting Administrative statewide database. Methods WLS records for women with non-metastasized breast (n=395,146) or endometrial (n=69,859) cancer were identified from the 1991-2014 California Cancer Registry data linked with the California Office of Statewide Health Planning and Development database. Characteristics of the patients were examined according to history of WLS. Using body mass index data available since 2011, a retrospective cohort of breast and endometrial cancer patients with obesity (n=12,540) was established and followed until 2017 (5% loss-to-follow-up). Multivariable cause-specific Cox proportional hazards models were used to examine the associations between post-diagnostic WLS and time to death. Results WLS records were identified for 2,844 (0.7%) breast and 1,140 (1.6%) endometrial cancer patients; about half of the surgeries were performed after cancer diagnosis. Post-diagnosis WLS was performed in ∼1% of patients with obesity and was associated with a decreased hazard for death (cause-specific hazard ratio=0.37; 95% confidence interval=0.014-0.99; P=0.049), adjusting for age, stage, comorbidity, race/ethnicity, and socioeconomic status. Conclusions About 2,000 breast or endometrial cancer patients in California underwent post-diagnosis WLS between 1991 and 2014. Our data support survival benefits of WLS after breast and endometrial cancer diagnosis.