Abstract GS5-02: Cardiovascular function and the effect of exercise training during adjuvant breast cancer treatment. Results from The EBBA-II trial

Abstract

Abstract Background: Breast cancer survival rates have improved, but cardiovascular disease is a competing cause of death among breast cancer survivors, and treatment-induced cardio-toxicity remains a major concern. The effect of aerobic exercise on cardiovascular function during adjuvant breast cancer treatment is not yet well established. Material & methods: The women participating in the Energy Balance and Breast Cancer Aspect (EBBA)-II trial are aged 18-75 years and diagnosed with stage I-II breast cancer. VO2max was assessed at three separate times, prior to surgery and at 6 and 12 months after, using a maximum exercise test on a treadmill (modified Balke protocol).The patients were randomized after surgery to a control group (n=188, usual care) or an intervention group (n=187) stratified by menopausal status. The 12 months exercise intervention program started 2-3 weeks after surgery and the patients received a detailed training program based on their own VO2max at baseline. They met for training sessions in groups of 10-12 women for 60 minutes twice a week during a 12 month period, and were in addition asked to perform at least 120 minutes of exercise at home (a total of 240 minutes of exercise weekly).Analyses were done on an intention-to-treat basis (NCT02240836). Preliminary results: Breast cancer patients (n=375) with a mean age at diagnosis of 55.2 years (27.0-75.0 years) had a mean body mass index (BMI) of 25.1kg/m2, a mean VO2max before surgery of 31.5 ml•min−1•kg−1, and 57 % of the patients underwent chemotherapy (paclitaxel, epirubicin/cyclophosphamide based adjuvant chemotherapy). Comparing the intervention group to the control group, the intervention group had a decrease in VO2max of 2.7% after 6 months, but they improved their VO2max by 2.3 % at 12 months compared to before surgery (p=0.001). Breast cancer patients in the control group had a 10 % reduction in VO2max 6 months after surgery (p<0.001), and a 3.8% decrease in VO2max was observed at 12 months compared to before surgery (p<0.001). Among patients in the control group who received chemotherapy, a decline in VO2max by 5.3 ml•min−1•kg−1 (16.2%) (p<0.001) at 6 months was observed. This reduction in VO2max at 6 months was most pronounced in patients who received paclitaxel alone, or paclitaxel in combination with epirubicin/cyclophosphamide (6.1 ml•min−1•kg−1, 18.7% decrease). In comparison, patients in the intervention group who received chemotherapy had a decline of 2.4 ml•min−1•kg−1 (7.6%) in VO2max at 6 and after 12 months VO2max was equal to before surgery. Differences in VO2max at 6 and after 12 month between groups were in favor of the intervention group (p<0.05). Conclusion: Our findings strongly support that tailored exercise training during adjuvant breast cancer treatment may counteract a decline in cardiovascular function, and in particular among those receiving chemotherapy. Our study supports incorporation of supervised clinical exercise programs into breast cancer treatment guidelines. Final results of the trial at SABCS 2018 (the trial closes October 15, 2018) total included N=539 (NCT02240836) Citation Format: Thune I, Husøy A, Frydenberg H, Flote VG, Fjeldheim F, Bertheussen GF, Lundgren S, Lømo J, Wist EA, McTiernan A, Schlichting E. Cardiovascular function and the effect of exercise training during adjuvant breast cancer treatment. Results from The EBBA-II trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS5-02.