Funding
NIH
NCI
Department of Health and the University of Utah
National Cancer Institute
Memorial Sloan Kettering Cancer Center
Core
ARTICLE ABSTRACT
To investigate whether the impact of postdiagnosis exercise on breast cancer outcomes in women diagnosed with early-stage breast cancer differs on the basis of tumor clinicopathologic and molecular features. Using a prospective design, 6,211 patients with early-stage breast cancer from two large population-based cohort studies were studied. Age-adjusted and multivariable Cox regression models were performed to determine the relationship between exercise exposure (total MET-hours/week) and recurrence and breast cancer–related death for: (i) all patients (“unselected” cohort), and on the basis of (ii) classic clinicopathologic features, (iii) clinical subtypes, (iv) PAM50-based molecular intrinsic subtypes, and (v) individual PAM50 target genes. After a median follow-up of 7.2 years, in the unselected cohort (n = 6,211) increasing exercise exposure was not associated with a reduction in the risk of recurrence (adjusted Ptrend = 0.60) or breast cancer–related death (adjusted Ptrend = 0.39). On the basis of clinicopathologic features, an exercise-associated reduction in breast cancer–related death was apparent for tumors <2 cm [HR, 0.50; 95% confidence interval (CI), 0.34–0.72], well/moderately differentiated tumors (HR, 0.63; 95% CI, 0.43–0.91), and ER-positive tumors (HR, 0.72; 95% CI, 0.53–0.97). Stratification by clinical subtype indicated that the ER+/PR+/HER2−/low-grade clinical subtype was preferentially responsive to exercise (recurrence: adjusted HR, 0.63; 95% CI, 0.45–0.88; breast cancer–related death: adjusted HR, 0.57; 95% CI, 0.37–0.86). The impact of exercise on cancer outcomes appears to differ as a function of pathologic and molecular features in early-stage breast cancer. Cancer Res; 76(18); 5415–22. ©2016 AACR.
