Feasibility of a lifestyle intervention on body weight and serum biomarkers in breast cancer survivors with overweight and obesity.

Physical inactivity and being overweight or obese are lifestyle factors that put breast cancer survivors at a higher risk for a cancer recurrence and/or development of other chronic diseases. Despite this, there is limited research that has identified effective lifestyle interventions aimed specifically at weight loss in breast cancer survivors. This pilot study is a single-arm experimental pre–post test design, conducted from November 2009 to July 2010, that tested the efficacy of a 24-week group-based lifestyle intervention modeled on the Diabetes Prevention Program in early stage breast cancer survivors (N=14). The intervention included 16 diet sessions led by a registered dietitian and 150 min/wk of moderate-to-vigorous exercise. Study outcome measures were completed at baseline, 24, and 36 weeks (nonintervention follow-up). The primary outcome was change in body weight, and secondary outcomes were change in body composition, aerobic fitness, dietary intake, and blood biomarkers. Overall, participants were postmenopausal women aged 54.6±8.3 years with obesity (body mass index 30.1±3.6), and had completed adjuvant cancer treatment 2 years prior. Results showed an average weight loss of 3.8±5.0 kg and a decrease in body mass index, percent body fat, and waist and hip circumferences at 24 weeks and an additional mean weight loss of 0.8±1.2 kg at 36 weeks. In exploratory analysis, participants who lost >7% body weight were older and attended a greater percentage of diet and supervised exercise sessions. There were no significant changes in any of the blood biomarkers at 24 and 36 weeks; however, the results provide a measure of expected effect size for future research studies. This pilot study demonstrated the efficacy of a lifestyle intervention based on the Diabetes Prevention Program in early stage breast cancer survivors and represents an innovative clinical intervention for dietetics practitioners to address the unmet need for programs.