William J. Gradishar, MD reviewing Jones LW et al. J Clin Oncol 2016 May 23.
An increase in exercise was associated with a decrease in cardiovascular events, the leading cause of death in women with nonmetastatic breast cancer.
Key objectives for breast cancer survivors are to get “back to their lives” and enhance their overall health. Exercise guidelines to meet these goals have been published for adult survivors, but adherence to the recommendations and their impact on downstream cardiovascular events are unclear. To examine these issues, investigators studied 2973 women (median age, 57) with nonmetastatic breast cancer (stage I–III) selected from two registry-based, regional cohort studies (LACE, Cancer Causes Control 2005; 16:545, and Pathways, Cancer Causes Control 2008; 19:1065).
A validated questionnaire was used to evaluate various types of exercise (walking, jogging, running, bicycling, swimming, etc.), and a metabolic equivalent task (MET) measure that took into account frequency and duration was assigned to each activity, resulting in a MET-hours per week (MET-h/wk) metric. The national guidelines for exercise in adult cancer survivors calls for three to five moderate or vigorous exercise sessions of ≥20 minutes each per week, the equivalent of ≥9MET-h/wk. The primary endpoint of the study was the first occurrence of a new diagnosis of coronary artery disease, heart failure, valve abnormality, arrhythmia, stroke, or cardiovascular death after enrollment.
At median follow-up of 8.6 years, investigators found that as exercise increased beyond the least amount/week (<2.0 MET-h/wk), cardiovascular events decreased. Specifically, hazard ratios were >0.91 for 2.0 to 10.9 MET-h/wk, 0.79 for 11.0 to 24.5 MET-h/wk, and 0.65 for ≥24.5 MET-h/wk. Patients who met the ≥9 MET-h/wk guideline minimum achieved a 23% reduction in cardiovascular events. The benefit did not differ based on existing cardiovascular risk factors, menopausal status, or the type of cancer treatment received.
Jones LW et al. Exercise and risk of cardiovascular events in women with nonmetastatic breast cancer. J Clin Oncol 2016 May 23; [e-pub].