Moderate Intensity Exercise Reduces Side Effects of Cancer Therapy and Maintains Cardiorespiratory Fitness in Male Breast Cancer Patients: Findings from the BRECA Male Crossover Study

Abstract

Introduction: There is growing evidence that aerobic exercise mitigates cancer therapy-related side effects and improves cardiorespiratory fitness (CRF). However, to the best of our knowledge, no exercise study has been conducted in male breast cancer (MBC) patients. The aim of this study was to investigate the feasibility and efficacy of different exercise intensities on CRF and self-reported questionnaire items in MBC patients. Methods: Twenty-two MBC patients (60 ± 9 years) participated in this randomized crossover study. After completion of medical treatment, MBC patients were randomly assigned to either moderate (40-50% of heart rate [HR] max. and self-perceived exertion: 11) or vigorous (70-80% of HR max. and self-perceived exertion: 15) exercise intensity during the first 3 months of the study. After a 1-month washout period, participants switched group assignments. Primary endpoints were CRF and questionnaire items. Results: We observed a dropout rate of 36% over 7 months, with the number of participants decreasing from 22 to 14. The results showed significant improvements in "Physical Function"(p = 0.037) and "Social Function"(p = 0.016) after moderate training. A non-significant improvement was also observed in "Breast Symptoms"(p = 0.095), but there was no change in "Fatigue"(p = 0.306). There were no differences observed in cardiovascular fitness (V˙O2 peak) between the treatment groups. Conclusion: This study emphasizes the effectiveness of exercise intervention for an exceedingly rare cancer, highlighting the vital role of moderate intensity aerobic exercise in mitigating treatment side effects. Despite minimal peak V˙O2 differences, both exercise protocols adequately sustain CRF. Future studies are imperative to design optimized, sex-specific rehabilitation strategies tailored to the unique requirements of MBC patients, advancing our understanding of this under explored realm.