Weight Management and Physical Activity for Breast Cancer Prevention and Control.

Observational evidence has consistently linked excess adiposity and inactivity to increased breast cancer risk and to poor outcomes in individuals diagnosed with early-stage, potentially curable breast cancer. There is less information from clinical trials testing the effect of weight management or physical activity interventions on breast cancer risk or outcomes, but a number of ongoing trials will test the impact of weight loss and other lifestyle changes after cancer diagnosis on the risk of breast cancer recurrence. Lifestyle changes have additional benefits beyond their potential to decrease primary or secondary breast cancer risk, including improvements in metabolic parameters, reduction in the risk of comorbidities such as diabetes and heart disease, improvement of physical functioning, and mitigation of side effects of cancer therapy. Despite these myriad benefits, implementation of lifestyle interventions in at-risk and survivor populations has been limited to date. This article reviews the evidence linking lifestyle factors to breast cancer risk and outcomes, discusses completed and ongoing randomized trials testing the impact of lifestyle change in primary and secondary breast cancer prevention, and reviews efforts to implement and disseminate lifestyle interventions in at-risk and breast cancer survivor populations.