Weight Gain After Breast Cancer Diagnosis and All Cause Mortality: Systematic Review and Meta Analysis.
BACKGROUND Overweight and obesity are associated with breast cancer mortality. However, the relationship between postdiagnosis weight gain and mortality is unclear. We conducted a systematic review and meta analysis of weight gain after breast cancer diagnosis and breast cancer specific, all cause mortality and recurrence outcomes. METHODS Electronic databases identified articles up through December 2014, including: PubMed (1966 present) EMBASE (1974 present) CINAHL (1982 present) and Web of Science. Language and publication status were unrestricted. Cohort studies and clinical trials measuring weight change after diagnosis and all cause/breast cancer specific mortality or recurrence were considered. Participants were women age 18 years or older with stage I IIIC breast cancer. Fixed effects analysis summarized the association between weight gain =5.0% body weight) and all cause mortality; all tests were two sided. RESULTS Twelve studies (n 23 832) were included. Weight gain =5.0% compared with maintenance 5.0% was associated with increased all cause mortality (hazard ratio [HR] 1.12, 95% confidence interval [CI] 1.03 to 1.22, P .01, I(2) 55.0% Higher risk of mortality was apparent for weight gain =10.0% (HR 1.23, 95% CI 1.09 to 1.39, P .001) 5% to 10.0% weight gain was not associated with all cause mortality (P .40) The association was not statistically significant for those with a prediagnosis body mass index (BMI) of less than 25 kg/m(2) (HR 1.14, 95% CI 0.99 to 1.31, P .07) or with a BMI of 25 kg/m(2) or higher (HR 1.00, 95% CI 0.86 to 1.16, P .19) Weight gain of 10.0% or more was not associated with hazard of breast cancer specific mortality (HR 1.17, 95% CI 1.00 to 1.38, P .05) CONCLUSIONS Weight gain after diagnosis of breast cancer is associated with higher all cause mortality rates compared with maintaining body weight. Adverse effects are greater for weight gains of 10.0% or higher.
Journal of the National Cancer Institute