Perturbations of Adjuvant Chemotherapy on Cardiovascular Responses and Exercise Tolerance in Patients with Early-Stage Breast Cancer

Simple Summary The present study aimed to assess and compare the effects of receiving CAF (cyclophosphamide/doxorubicin/fluorouracil) and AC-T (doxorubicin/cyclophosphamide -> taxanes) on exercise tolerance and cardiovascular responses in patients with early-stage breast cancer. We herein demonstrated that AC-T chemotherapy increased resting heart rate (RHR) and induced a greater reduction in exercise tolerance at the end of chemotherapy compared with CAF. Moreover, AC-T also lowered myocardial perfusion more than CAF, and it appeared that myocardial impairment occurred before the development of arterial stiffening after chemotherapy. We, therefore, suggest that AC-T chemotherapy might further limit the exercise capacity of patients with early-stage breast cancer. This study provides fundamental information regarding the variety of cardiovascular responses to exercise after chemotherapy in patients with early-stage breast cancer. This information will help clinical professionals in the fields of oncological and rehabilitation medicine to precisely prescribe post-chemotherapy exercise programs when patients are receiving different chemotherapies. Background: Adjuvant chemotherapies are commonly used for treating early-stage breast cancer. However, whether chemotherapeutic regimens affect exercise tolerance and cardiovascular responses remains unclear. Therefore, we investigated the effects of receiving CAF and AC-T on exercise tolerance and cardiovascular responses in patients with early-stage breast cancer. Methods: Thirty-four patients with breast cancer (age: 44 +/- 1 years; stage I-II) received either CAF (n = 15) or AC-T (n = 19), depending on clinical decisions. Their step-exercise tolerance and cardiovascular responses were assessed before and after chemotherapy. Results: After chemotherapy, there were no differences in baseline measurements between patients receiving CAF or AC-T. The increases in resting heart rate (RHR) of those receiving AC-T was significantly greater than that of those receiving CAF. CAF and AC-T did not result in increased pulse wave velocity (PWV), yet the subendocardial viability ratio (SEVR) in patients receiving AC-T was significantly lower than the baseline. Greater change in post-exercise heart rate recovery (recovery HR) after chemotherapy was observed in those who had received AC-T; the Recovery HR in AC-T patients was significantly higher during post-exercise period than that in CAF patients. Conclusions: AC-T chemotherapy increases RHR and impairs exercise tolerance after chemotherapy more than CAF. Moreover, AC-T also lowers myocardial perfusion more than CAF after chemotherapy.