Changes in cardiorespiratory fitness, cardiovascular risk factors and patient reported outcomes in long-term breast cancer survivors after 5 months of aerobic exercise: a randomized controlled trial

Abstract Background Cancer treatment may impair the physiological adaptations to exercise training according to earlier exercise training trials. Nonetheless, reduced exercise training response has not been systematically studied in cancer survivors. Purpose To examine the effects of aerobic exercise on cardiorespiratory fitness (CRF) and cardiovascular (CV) risk factors in anthracycline-treated long-term breast cancer survivors (BCSs) and compared these effects with women without cancer following the same exercise program. Methods The CAUSE (CArdiovascUlar Survivors Exercise) trial was a two-armed randomized controlled trial, where long-term BCSs were assigned to five months of aerobic exercise training 3 times per week or to usual care. Similar-aged women without cancer underwent the same exercise program. CRF was assessed as peak oxygen consumption (V̇O2peak), and CV risk factors including cardiometabolic biomarkers and body composition were assessed at baseline and post-intervention. Patient-reported outcomes were assessed using the Subjective Vitality Scale (SVS) and the Satisfaction With Life Scale (SWLS). Results We included, 140 BCSs (aged 59.0±6.4 years), 11±1 years post-treatment, and 69 women without cancer (aged 57.8±4.9 years) between October 2020 and February 2023. Intervention adherence and loss to follow-up were similar between the exercise groups. VO2peak increased by 1.22±2.63 mL O2×kg-1×min-1 in BCSs after exercise training from baseline to post-intervention, 0.02±2.47 mL O2×kg-1×min-1 in BCSs after usual care mean difference 1.32 (95% CI: 0.501; 2148), p=0.002 and 2.64±2.51mL in women without cancer after exercise training BCSs exercise training VS. women without cancer: Mean difference -1.41, (95% CI: -2.267; -0.545), p=0.002. There were no significant changes in CV risk factors from baseline to post-intervention between the groups. SVS mean difference 2.56, (95% CI: 1.215; 3.897), p=0.001 and SWLS mean difference 1.68, (95% CI: 0.428; 2.932), p=0.009) significantly improved in BCSs after exercise training compared to BCSs after usual care, with greater changes in SWLS in BCSs after exercise training compared to women without cancer [mean difference 1.71, (95% CI: 0.262; 2.157), p=0.021. Conclusion A decade after anthracycline treatment, aerobic exercise training improves CRF in long-term BCSs. Importantly, however, the exercise training response was lower in BCSs compared to women without cancer.