RESUMEN
BACKGROUND: Chemotherapy for breast cancer can increase the risk of cancer therapy related cardiac dysfunction (CTRCD). Exercise has been proposed to prevent CTRCD, however, research to date has indicated high degrees of individual variability following exercise interventions in this population. AIM: This study aimed to explore the impact of regular, individualized aerobic exercise on CTRCD incidence (defined by global longitudinal strain [GLS]) during and immediately upon the completion of dose-dense anthracycline (DDAC) chemotherapy in 5 women with breast cancer. METHODS: Five women receiving DDAC with stage I-III breast cancer enrolled. Participants underwent resting echocardiography and exercise testing before, during, upon the completion of, and 3 months after the completion of DDAC treatment to measure GLS and aerobic fitness (VO2peak). Participants opted-in to an individualized 8-week aerobic exercise intervention (3 sessions per week, 24 sessions total) or standard care for the duration of their DDAC treatment. Data for each participant were presented descriptively. RESULTS: Four of the 5 participants completed the exercise intervention during DDAC treatment (adherence 79.2%-91.7%). Mild asymptomatic CTRCD occurred in 2 of the 4 exercising participants, of whom both were at an increased risk (one was >65 years of age and diagnosed with hypertension, with the other receiving trastuzumab prior to DDAC treatment). Varied responses in VO2peak were observed and did not align with changes in GLS. The only participant not to complete the exercise intervention reported poorer health related quality of life and increased cancer related fatigue at all measurement timepoints. CONCLUSION: This study details the individual variability in cardiovascular responses to exercise that can occur during DDAC treatment in women with breast cancer, which can inform exercise professionals and researchers when designing individualized exercise programs for this population.