Effects of exercise intervention in breast cancer survivors: a meta-analysis of 33 randomized controlled trails

BACKGROUND Exercise is associated with favorable outcomes in cancer survivors. The purpose of this meta-analysis is to comprehensively summarize the effects of exercise intervention in breast cancer survivors. METHODS A systematic search of PubMed, Elsevier, and Google scholar was conducted up to March 2015. References from relevant meta-analyses and reviews were also checked. RESULTS Thirty-three randomized controlled trials were included in this meta-analysis, including 2,659 breast cancer survivors. Compared with the control group, quality of life was significantly improved in exercise intervention group, especially in mental health and general health subscales of short form 36 questionnaire, as well as emotion well-being and social well-being subscales of the Functional Assessment of Cancer Therapy. Besides, exercise alleviated the symptoms of depression and anxiety in the exercise group. Furthermore, exercise was also associated with positive outcomes in body mass index, lean mass, and muscle strength. In addition, the serum concentration of insulin, insulin-like growth factor-II, and insulin-like growth factor binding protein-1 was significantly reduced in exercise intervention group. However, based on the current data of this meta-analysis, there were no significant differences in sleep dysfunction or fatigue between groups. CONCLUSION Our study suggested that exercise intervention was beneficial to breast cancer survivors. Therefore, exercise should be recommended to this patient group.