The influence of adjuvant therapy on cardiorespiratory fitness in early-stage breast cancer seven years after diagnosis: the Cooper Center Longitudinal Study

Abstract

We examined cardiorespiratory fitness (CRF) levels in early stage breast cancer patients and determined whether CRF differs as a function of adjuvant therapy regimen. A total of 180 early breast cancer patients representing three treatment groups (surgery only, single-, and multi-modality adjuvant therapy) in the Cooper Center Longitudinal Study (CCLS) were studied. A non-cancer control group (n = 180) matched by sex, age, and date of the CCLS visit was included. All subjects underwent an incremental exercise tolerance test to symptom limitation to assess CRF (i.e., peak metabolic equivalents [METs] and time to exhaustion). The mean time from breast cancer diagnosis to exercise tolerance testing was 7.4 ± 6.2 years. In adjusted analyses, time to exhaustion and peak METs were incrementally impaired with the addition of surgery, single-, and multi-modality adjuvant therapy compared to those of matched controls (p = 0.006 and 0.028, respectively). CRF was lowest in the multi-modality group compared to all other groups (all p's < 0.05). Despite being 7 years post-diagnosis, asymptomatic early breast cancer survivors have marked reductions in CRF. Patients treated with multi-modal adjuvant therapy have the greatest impairment in CRF.

Figure 1

Differences in cardiorespiratory fitness between the overall cohort of breast cancer patients (n=180) and age-matched controls (n=180) for: (A) time to exhaustion and (B) peak METs. Statistical Tests: ^*p<0.05

Figure 2

Differences in cardiorespiratory fitness between breast cancer patients by prior adjuvant therapy for: (A) time to exhaustion (*significantly different from controls, surgery only, single modality adjuvant therapy, and multi-modal adjuvant therapy) and (B) peak METs (*significantly different from matched controls). Statistical Tests: ^*p<0.05