Exercise and Prognosis on the Basis of Clinicopathologic and Molecular Features in Early-Stage Breast Cancer: The LACE and Pathways Studies

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