Cardiorespiratory Fitness in Breast Cancer Patients: A Call for Normative Values

Background-There is emerging evidence that adjuvant treatments for breast cancer negatively impact cardiorespiratory fitness (CRF) or VO2max, a key predictor of cardiovascular risk. Although a number of studies have measured CRF in breast cancer patients, there is currently limited data regarding expected CRF values in this patient population. Given that CRF is a poor prognostic sign and recently highlighted as a key measure to standardize by the American Heart Association, we sought to review the available literature on CRF among breast cancer patients. Methods and Results-We identified 27 clinical trials and observational studies measuring VO2max in the pre- and post-adjuvant treatment setting for breast cancer. We compared VO2max before to VO2max after adjuvant therapy and compared VO2max in female breast cancer patients with VO2max in healthy controls. Conclusions-We found that CRF was substantially lower in women with a history of breast cancer compared with healthy women and this was most pronounced among breast cancer patients in the post-adjuvant setting. We conclude that knowledge of normative CRF values is critical to tailor appropriately timed exercise interventions in breast cancer patients susceptible to low CRF and subsequent cardiovascular risk.