Abstract PD2-6: Exercise dose and type effects in breast cancer patients receiving chemotherapy: A randomized trial

Abstract

Background: Aerobic and resistance exercise, either separately or in combination, have been shown to improve physical functioning and manage some symptoms in breast cancer patients receiving chemotherapy. Few exercise trials, however, have compared different doses or types of exercise in breast cancer patients to identify the optimal exercise prescription. Here, we report the primary results of the Combined Aerobic and Resistance Exercise (CARE) Trial which compared two different doses and types of exercise for improving physical functioning and symptom management in breast cancer patients receiving chemotherapy. Methods: A multicenter trial in Canada randomized 301 breast cancer patients between 2008 and 2011 to thrice weekly, supervised exercise during chemotherapy consisting of either a standard dose of 25-30 minutes of aerobic exercise (STAN; n = 96), a higher dose of 50-60 minutes of aerobic exercise (HIGH; n = 101), or a combined dose of 50-60 minutes of aerobic and resistance exercise (COMB; n = 104). The primary endpoint was patient-reported physical functioning assessed by the Medical Outcomes Survey-Short Form (SF)-36. Secondary endpoints were other physical functioning scales, symptoms, physical fitness, and chemotherapy completion. Results: Between April 2008 and September 2011, we randomized 301 of 728 (41%) eligible patients. STAN, HIGH and COMB completed 88% (43/49), 82% (40/49), and 78% (39/50) of their prescribed aerobic exercise sessions. We obtained patient-reported outcome data from questionnaires on 99% of patients at each point during and after chemotherapy. Adjusted linear mixed-model analyses showed that neither HIGH (+0.8; 95% CI [-0.8 to 2.4]; p = 0.30) nor COMB (+0.5; 95% CI [-1.1 to 2.1]; p = 0.52) were statistically superior to STAN for the primary outcome. For important secondary outcomes, HIGH was superior to STAN for the SF-36 physical component summary (p = 0.041), SF-36 bodily pain (p = 0.015), and endocrine symptoms (p = 0.019). COMB was superior to STAN for endocrine symptoms (p = 0.009) and superior to STAN (p<.001) and HIGH (p<.001) for muscular strength. HIGH was superior to COMB for the SF-36 bodily pain (p = 0.035) and aerobic fitness (p = 0.030). No differences resulted for body composition or chemotherapy completion. Relative dose intensity was 93.9% in STAN compared to 92.7% in COMB and 91.6% in HIGH (p = 0.34). No serious adverse events were related to exercise. Conclusions: A higher dose of aerobic or combined exercise compared to a standard dose of aerobic exercise did not improve patient-reported physical functioning as assessed by the SF-36 physical functioning subscale. The CARE Trial did demonstrate that higher doses of aerobic or combined exercise of up to 50-60 minutes/session are safe and feasible and do not interfere with chemotherapy completion or exacerbate any symptoms. Moreover, a higher dose of aerobic exercise was shown to provide modest improvements in aerobic fitness, patient-reported physical functioning, bodily pain, fatigue, and endocrine symptoms whereas combined exercise improved muscular fitness and endocrine symptoms. Cancer care professionals can safely recommend higher doses of exercise during breast cancer chemotherapy in appropriately supervised settings. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD2-6.