Weight Evolution During Endocrine Therapy for Breast Cancer in Postmenopausal Patients: Effect of Initial Fat Mass Percentage and Previous Adjuvant Treatments.

Background: Weight changes during adjuvant treatment for early-stage breast cancer has been associated with a poor prognosis. The long-term evolution of body composition during adjuvant treatment for breast cancer, in particular, endocrine therapy, is not well known, and new data on this topic are required. The present study assessed the evolution of weight and body composition among 33 postmenopausal breast cancer patients receiving endocrine therapy after standard adjuvant chemotherapy that included taxanes.
Patients and Methods: Dual-energy x-ray absorptiometry was used to measure the fat and lean body mass. Body water was assessed using multifrequency bioelectrical impedance analysis. The Hospital Anxiety and Depression questionnaire and the short version of the International Physical Activity Questionnaire were also administered.
Results: During endocrine therapy, 5 of the 33 patients (15.2%) lost weight and 12 (36.4%) gained weight. The overall average gain was 2.0 ± 5.5 kg (P = .04). During this period, the fat mass, lean body mass, and body water increased. The factors linked to fat mass gain included an excess fat mass (≥ 36%) before treatment and weight loss during chemotherapy. In the overall period of adjuvant cancer treatment, 30% of the population gained > 5% of their initial weight. The average gain was the same as that during the endocrine therapy period (2.0 ± 5.4 kg; P = .031) and was characterized by an increase in total lean body mass, mainly localized in the trunk region.
Conclusion: Endocrine therapy appears as a pivotal period in weight and body composition management. Overfat and obese patients and those who lose weight during chemotherapy were more subject to weight and fat mass gain during endocrine therapy.
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