Prospective, longitudinal study of leisure-time exercise in women with early-stage breast cancer.

Physical activity can have a beneficial effect on both physical and mental health in cancer survivors. However, evidence from cross-sectional and/or retrospective research suggests that cancer treatment can be associated with both short- and long-term reductions in physical activity. A prospective, longitudinal research design was used to examine the trajectory of leisure-time exercise in early-stage breast cancer patients from two treatment centers (n = 231). Participation in mild, moderate, and strenuous leisure-time exercise was assessed before, during, and following completion of adjuvant radiotherapy (n = 136) or chemotherapy + radiation (n = 95). Results indicated significant decreases, relative to pre-diagnosis baseline, in total estimated weekly metabolic equivalents and minutes of leisure-time exercise during adjuvant therapy for both the radiotherapy and chemotherapy + radiation groups. However, activity levels seemed to quickly recover and did not differ from pre-diagnosis baseline at assessments 2 and 6 months following completion of adjuvant radiotherapy or chemotherapy + radiation. Although suggesting little effect of breast cancer diagnosis and treatment on participation in leisure-time exercise at 6-month follow-up, these group analyses obscure the fact that a large number of individuals (35.5%) exhibited clinically significant change, both decreases or increases, in total weekly metabolic equivalents between pre-diagnosis baseline and 6-month follow-up. Fostering appropriate participation in physical activity in cancer patients and survivors is likely to be enhanced by better understanding of the beliefs and motivations that underlie spontaneous changes in participation in leisure-time exercise.