Is exercise beneficial in the prevention of prostate cancer?

Prostate cancer is the most frequently diagnosed cancer in men. Exercise has been studied as an alterable risk factor that may reduce the incidence, morbidity and mortality due to this cancer. Epidemiological studies play an important role in assessing the relationship between physical activity and prostate cancer. Studies have attempted to estimate physical activity level by measuring time spent in sports, leisure or occupational activity. We identified 17 studies that assessed the effect of exercise on the development of prostate cancer. Although methodological limitations could be identified in most of the studies, 9 suggested that exercise may be beneficial in decreasing prostate cancer risk, while 5 were null providing no conclusive evidence and 3 actually showed an increased risk of prostate cancer with increased physical activity. The bulk of the evidence at this time does not seem to support an overwhelmingly beneficial effect of exercise on prostate cancer risk. Future studies need to investigate the frequency, intensity and duration of physical activity as well as the type of activity and period during a man's lifetime when exercise might be beneficial. It is reasonable to conclude that exercise may be a potential factor that can be modified to prevent prostate cancer and it seems prudent to recommend that all men become physically active.