Physical activity is associated with reduced mortality in patients with breast and colon cancer, according to a study published in the Journal of the National Cancer Institute. So far, there is insufficient evidence to draw the same conclusion with other cancer types.
Exercise and its relationship to patient quality of life, cancer prevention, and impact on treatment and recurrence have been studied extensively in several types of cancer. Regular physical activity may help improve overall health and well-being as well as treatment outcomes. Experts have recommended that cancer patients and survivors continue to stay active.
In order to examine the association between physical activity and cancer survival, researchers reviewed 45 studies (between 1950 and 2011) that evaluated the relationship between physical activity and mortality and/or cancer biomarkers among cancer survivors. They found consistent evidence that physical activity is associated with reduced mortality in breast and colon cancer patients and survivors (and this refers to mortality associated to any cause, not just the cancer). The studies that included biomarker endpoints provided evidence that exercise might result in beneficial changes in the circulating level of insulin, insulin-related pathways, inflammation, and possibly, immunity; however, the researchers point out that more evidence is required to make any conclusions.
The strongest evidence associated with a benefit from exercise was in breast cancer survivors, with colorectal cancer coming in a close second. Most studies showed a significant reduced risk of breast cancer mortality associated with exercise. Because the studies were so diverse, it is not possible to provide specific recommendations regarding the type and duration of exercise; however, the evidence is clear—exercise provides benefit.
 Ballard-Barbash, R, Friedenreich CM, Courneya KS, et al. Physical Activity, Biomarkers, and Disease Outcomes in Cancer Survivors: A Systematic Review. Journal of the National Cancer Institute. Published early online, May 8, 2012. doi: 10.1093/jnci/djs207
 Schmitz KH, Courneya KS, Matthews C, et al. American College of Sports Medicine Roundtable on Exercise Guidelines for Cancer Survivors. Medicine & Science in Sports & Exercise. 2010;42:1409–26.
Posted May 24, 2012