Physical Activity and Survival after Diagnosis of Invasive Breast Cancer

^{1 1}Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, Washington; ²Paul P. Carbone Comprehensive Cancer Center and ³Department of Population Health Sciences, University of Wisconsin, Madison, Wisconsin; ⁴Department of Community and Family Medicine and Norris Cotton Cancer Center, ⁵Department of Pediatrics, and ⁶Department of Medicine, Dartmouth Medical School, Lebanon, New Hampshire; ⁷Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School; ⁸Departments of Epidemiology and Nutrition, Harvard School of Public Health, Boston, Massachusetts; and ⁹Moffitt Cancer Center and Research Institute and University of South Florida, Tampa, Florida

^* To whom correspondence should be addressed. E-mail: crystal.holick{at}i3drugsafety.com.

	Abstract

Previous studies suggest that increased physical activity may lower the risk of breast cancer incidence, but less is known about whether levels of physical activity after breast cancer diagnosis can influence survival. We prospectively examined the relation between postdiagnosis recreational physical activity and risk of breast cancer death in women who had a previous invasive breast cancer diagnosed between 1988 and 2001 (at ages 20-79 years). All women completed a questionnaire on recent postdiagnosis physical activity and other lifestyle factors. Among 4,482 women without history of recurrence at the time of completing the questionnaire, 109 died from breast cancer within 6 years of enrollment. Physical activity was expressed as metabolic equivalent task-hours per week (MET-h/wk); hazard ratios (HR) and 95% confidence intervals (95% CI) were estimated using Cox proportional hazards regression. After adjusting for age at diagnosis, stage of disease, state of residence, interval between diagnosis and physical activity assessment, body mass index, menopausal status, hormone therapy use, energy intake, education, family history of breast cancer, and treatment modality compared with women expending <2.8 MET-h/wk in physical activity, women who engaged in greater levels of activity had a significantly lower risk of dying from breast cancer (HR, 0.65; 95% CI, 0.39-1.08 for 2.8-7.9 MET-h/wk; HR, 0.59; 95% CI, 0.35-1.01 for 8.0-20.9 MET-h/wk; and HR, 0.51; 95% CI, 0.29-0.89 for 21.0 MET-h/wk; P for trend = 0.05). Results were similar for overall survival (HR, 0.44; 95% CI, 0.32-0.60 for 21.0 versus <2.8 MET-h/wk; P for trend <0.001) and were similar regardless of a woman’s age, stage of disease, and body mass index. This study provides support for reduced overall mortality and mortality from breast cancer among women who engage in physical activity after breast cancer diagnosis. (Cancer Epidemiol Biomarkers Prev 2008;17(2):379–86)

Key Words: physical activity, survival, breast cancer, prospective study, epidemiology

This article has been cited by other articles:

				M. L. Irwin, A. W. Smith, A. McTiernan, R. Ballard-Barbash, K. Cronin, F. D. Gilliland, R. N. Baumgartner, K. B. Baumgartner, and L. Bernstein Influence of Pre- and Postdiagnosis Physical Activity on Mortality in Breast Cancer Survivors: The Health, Eating, Activity, and Lifestyle Study J. Clin. Oncol., August 20, 2008; 26(24): 3958 - 3964. [Abstract] [Full Text] [PDF]