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.