The National Cancer Institute has a great fact sheet on the benefits of physical activity in regards to cancer and cancer survivorship.
• Physical activity is a critical component of energy balance, the term researchers use to describe how weight, diet, and physical activity influence health.
• There is strong evidence that physical activity is associated with reduced risk of cancers of the colon and breast.
• Several studies have also reported links between physical activity and reduced risk of endometrial (lining of the uterus), lung, and prostate cancers.
• Current National Cancer Institute-funded studies are exploring the role of physical activity in cancer survivorship and quality of life, cancer risk, and the needs of populations at increased risk.
Source: National Cancer Institute