The impact of an exercise intervention on body composition, fat distribution, and weight in breast cancer survivors

Abstract

590 Background: Recent research has demonstrated that obesity increases a woman’s risk of breast cancer recurrence. Although the mechanism is not well understood, it is known that obese women have higher levels of insulin and other hormones related to energy balance. In this study, we sought to explore the impact of an exercise intervention on body composition, fat distribution, weight, and insulin levels in a population of breast cancer survivors. Methods: Inactive women with early stage breast cancer who had completed adjuvant chemotherapy and/or radiation were randomized to a 16-week exercise intervention or a normal care control group. The exercise intervention consisted of supervised strength training and unsupervised cardiovascular exercise, with a goal of 2 strength training sessions and 90 minutes of cardiovascular exercise each week. Measurement of weight, body composition, and circumference at the waist and hip, were collected at baseline and after 16 weeks in both groups. Fasting blood samples were also collected at these two time points for insulin and glucose levels, so that changes in these levels between the intervention and control groups could be compared. Results: Eighty-five women have been randomized; complete anthropometric data are presently available for 51. Women in the exercise group experienced a nonsignificant decrease in body weight, body fat, and circumference at the waist and hip, as compared to control patients. Participants completed a median of 84% of scheduled strength training sessions and 80% of recommended cardiovascular sessions. Strength increased by an average of 40% during the exercise intervention. Prior studies have demonstrated significant inter-assay variability in biomarker testing, thus insulin and glucose testing will be performed when all patients have completed the protocol. Conclusions: Compliance with the exercise intervention was good. Women in the exercise group experienced non-significant changes in anthropometric measures, and increased strength during the 16-week intervention. Final strength and anthropometric data from the entire cohort will be available for presentation. This project was supported by an ASCO Career Development Award and funding from the Lance Armstrong Foundation. No significant financial relationships to disclose.