Cardiopulmonary Function and Age-Related Decline Across the Breast Cancer Survivorship Continuum

Abstract

Purpose To evaluate cardiopulmonary function (as measured by peak oxygen consumption [VO2peak]) across the breast cancer continuum and its prognostic significance in women with metastatic disease. Patients and Methods Patients with breast cancer representing four cross-sectional cohorts—that is, (1) before, (2) during, and (3) after adjuvant therapy for nonmetastatic disease, and (4) during therapy in metastatic disease—were studied. A cardiopulmonary exercise test (CPET) with expired gas analysis was used to assess VO2peak. A Cox proportional hazards model was used to estimate the risk of death according to VO2peak category (< 15.4 v ≥ 15.4 mL · kg−1 · min−1) with adjustment for clinical factors. Results A total of 248 women (age, 55 ± 8 years) completed a CPET. Mean VO2peak was 17.8 ± a standard deviation of 4.3 mL · kg−1 · min−1, the equivalent of 27% ± 17% below age-matched healthy sedentary women. For the entire cohort, 32% had a VO2peak less than 15.4 mL · kg−1 · min−1—the VO2peak required for functional independence. VO2peak was significantly different across breast cancer cohorts for relative (mL · kg−1 · min−1) and absolute (L · min−1) VO2peak (P = .017 and P < .001, respectively); VO2peak was lowest in women with metastatic disease. In patients with metastatic disease (n = 52), compared with patients achieving a VO2peak ≤ 1.09 L · min−1, the adjusted hazard ratio for death was 0.32 (95% CI, 0.16 to 0.67, P = .002) for a VO2peak more than 1.09 L · min−1. Conclusion Patients with breast cancer have marked impairment in VO2peak across the entire survivorship continuum. VO2peak may be an independent predictor of survival in metastatic disease.