Pre-diagnosis exercise may improve CV outcomes in older breast cancer survivors
Among long term survivors of primary breast cancer, a high level of exercise pre-diagnosis significantly reduced risk for CV events after diagnosis.
According to the study published in the inaugural issue of JACC: CardioOncology, over the course of the median 8.2-year follow-up of breast cancer survivors, incidence of CV events decreased with more hours of exercise, measured as metabolic equivalent task hours per week (P for trend = .016).
Additionally, compared with individuals who had less than 2.5 pre-diagnosis metabolic equivalent task (MET) hours per week, CV risk decreased with greater MET hours per week (adjusted HR for 2.5 to < 8.6 MET hours per week = 0.8; 95% CI, 0.59-1.09; aHR for 8.6 to < 18 MET hours per week = 0.9; 95% CI, 0.64-1.17; aHR for 18 MET hours per week = 0.63; 95% CI, 0.45-0.88).
Exercise may be protective
“This study is the first to show the exposure to exercise prior to a cancer diagnosis may potentially protect against or mitigate the established adverse cardiovascular consequences observed in breast cancer patients, adding to the growing evidence base supporting the importance of exercise to prevent cardiovascular events in high-risk populations,” Tochi M. Okwuosa, DO, director of the cardio-oncology program at Rush University Medical Center, said in a press release.
In other findings, during the median 12.7-year follow up analyzing CV death in breast cancer survivors, researchers observed a trend of decreasing mortality in each category of increasing pre-diagnosis MET hours per week: 2.5 to 8.6 MET hours per week (aHR compared with < 2.5 = 0.58; 95% CI, 0.36-0.99), 8.6 to 18 (aHR compared with < 2.5 = 0.45; 95% CI, 0.26-0.79) and more than 18 hours per week (aHR compared with < 2.5 = 0.4; 95% CI, 0.22-0.72).
However, the researchers found no significant multivariable-adjusted trend associated to pre-diagnosis MET hours per week for HF (P for trend = .366) or MI (P for trend = .373).
“As hypothesized, our primary analyses demonstrated that pre-diagnosis exercise was associated with a 20% to 37% reduction in the risk of CV events, even after controlling for important clinical covariates including pre-existing CV risk factors and other chronic health conditions,” the authors wrote. “However, risk of individual events — specifically, MI and HF — were not affected, suggesting that exercise may confer greater risk reduction in other events included in the composite endpoint, such as angina, coronary revascularization, peripheral artery disease or stroke.”
In this study, 4,015 postmenopausal women aged between 50 and 79 years with confirmed diagnosis of primary breast cancer enrolled in the Women’s Health Initiative completed a self-report questionnaire that assessed exercise as measured by MET hours per week. Researchers used these data to assess the association between pre-diagnosis exercise and subsequent CV events, with primary endpoints including HF, MI, angina, coronary revascularization, PAD, carotid artery disease, transient ischemic attack and stroke, and the secondary endpoint being CV death.
Strategies for exercise
In a related editorial, Lindsay L. Peterson, MD, MSCR, assistant professor of medicine at Washington University School of Medicine in St. Louis, and Jennifer A. Ligibel, MD, director of the Leonard P. Zakim Center for Integrative Therapies and Healthy Living at the Dana-Farber Cancer Institute, wrote the results emphasize the need for strategies to increase exercise.
“As more and more patients survive their breast cancer, cardiovascular disease is and will continue to become a major risk of morbidity and mortality for survivors,” Peterson and Ligibel wrote. “Finding strategies to help patients engage in recommended amounts of physical activity before and after a breast cancer diagnosis will be critical to improving outcomes in women with early breast cancer, in particular in the rising number of older adults with breast cancer.” – by Scott Buzby
Disclosures: The authors report no relevant financial disclosures. Ligibel reports she is supported by the Susan G. Komen Foundation under grant support and receives in-kind product donations from Fitbit and Nestle. Peterson reports she is supported by the American Cancer Society.