Weight Reduction Intervention for Breast Cancer Survivors

Overview

Overweight or obesity is an established negative prognostic factor in both premenopausal and postmenopausal breast cancer. Several mechanisms have been proposed to explain the adverse effect of excess body fat on prognosis following the diagnosis of breast cancer, including increased circulating sex hormones, insulin, leptin, and various growth factors. Results from previous studies suggest that specific strategies can facilitate weight reduction and maintenance of weight loss in this target population. This randomized clinical trial will recruit 253 overweight or obese women who have been previously treated for early stage breast cancer and will test whether a multifaceted approach to promoting healthy weight management can achieve the goal of weight loss and maintenance. Additionally, this study tests whether weight loss is associated with changes in biological and psychosocial factors, including eating attitudes and behaviors and health-related quality of life. The intervention incorporates cognitive-behavioral therapy, increased physical activity, diet modification to facilitate a modest reduction in energy intake, and strategies to improve body image and self-acceptance. This approach and intervention have been pilot-tested with breast cancer survivors in a developmental project, which resulted in the intervention group losing significantly more weight than the wait-list control group. Study Aims include: testing whether an intervention that emphasizes increased physical activity and individualized diet modification to promote an energy imbalance is associated with a greater degree of weight loss and maintenance of that loss over an 18-month time period; describing the effect of the intervention on hormones and growth factors; describing the relationships between body weight and weight reduction and measures of selected psychosocial factors. Measurements of hormonal and psychosocial factors in this study will provide insight into the responsiveness of these factors to weight loss in overweight or obese breast cancer survivors, which will provide an indication of the degree of clinical benefit that is achieved with the intervention efforts. Results from this study may enable the development of broader efforts transferable to clinical practice and public health, and thus, may ultimately have a substantial effect on the risk for recurrence and long-term survival of the estimated 1.98 million breast cancer survivors in the U.S. today.

Background: Overweight or obesity is an established negative prognostic factor in both premenopausal and postmenopausal breast cancer. Adverse effects of adiposity on prognosis may be explained by effects on gonadal hormones, insulin, insulin-like growth factor (IGF)-I, IGF binding proteins (IGFBPs), and leptin. Objective/Hypothesis: This study tests whether a multifaceted approach can achieve weight loss and maintenance in overweight or obese breast cancer survivors. The intervention incorporates cognitive-behavioral therapy, increased physical activity, diet modification, and strategies to improve body image and self-acceptance. This approach and intervention were developed and pilot-tested with support from a previous peer-reviewed grant. Weight change from baseline to one year in the pilot study (n=85) was -5.2 (6.3) kg (mean \[SD\]) in the intervention group vs. -0.1 (6.5) kg in the control group (P \< 0.05), using intent to treat analysis with baseline values carried forward for dropouts. Specific aims: (1) To test whether the intervention promotes weight loss and maintenance of that loss over an 18-month time period in a larger group; (2) To describe the effect of the intervention on hormonal factors (insulin, leptin, IGF-I, IGFBP-1, IGFBP-3, sex-hormone binding globulin, and serum estrogens); and (3) To describe the relationships between body weight and weight reduction and measures of psychosocial factors (health-related quality of life, fatigue, depression, eating attitudes, and weight and shape concerns). Study design: The study targets 253 overweight or obese women previously treated for early stage breast cancer and utilizes a randomized study design with subjects assigned to the group-based healthy weight management program (with individualized telephone counseling support) or a wait-list control group. Data collection includes anthropometric and psychosocial measures, body composition (dual-energy x-ray absorptiometry), cardiopulmonary fitness testing, and hormonal measures at baseline and six and 18 months.