Impact of Weight Loss Interventions for Overweight Breast Cancer Survivors

Obesity is an epidemic and the majority of breast cancer survivors are overweight or obese. The American Cancer Society has called for weight loss treatment to be standard of care for overweight women with breast cancer. During therapy women with breast cancer often gain weight and lose lean muscle mass. Overweight breast cancer survivors are more likely to have their cancer come back. The reason why overweight breast cancer survivors are more likely to re-occur has not been well studied, but changes in how insulin works may contribute. Overweight survivors are also at risk for the other chronic diseases associated with obesity. Fortunately, weight losses of as little as 5-7% of baseline body weight can improve risk of chronic disease. An effective behaviorally-based, lifestyle intervention delivered via the internet has been developed at the University of Vermont. This successful intervention has not been tested among breast cancer survivors. Given that women tend to lose muscle mass during cancer therapy the addition of a resistance training component to the weight loss intervention may be important. Therefore the overall goal of this project is to pilot test a proven distantly- delivered behavioral weight loss intervention among overweight breast cancer survivors and to evaluate whether a resistance program results in improvements in lean body mass, while studying how both interventions change insulin sensitivity.

Specifically, this project is a randomized, controlled clinical trial designed to test the effectiveness and acceptability of a 6-month behavioral weight loss intervention with and without resistance training. Participants will be randomized to one of two groups: 1) behavioral weight control treatment via the Internet; or 2) behavioral weight control treatment via the Internet plus a resistance training program. Women eligible to participate include overweight breast cancer survivors who are age 50 or older and 6-36 months past receiving chemotherapy. Assessments will be conducted at baseline and six months and will include measures of body weight, muscle mass, adherence to treatment, and insulin sensitivity.