Women undergoing radiation treatment for breast cancer benefit from moderate intensity, regular aerobic activity, according to a new study. Published in the November 15, 2006 issue of CANCER, a peer-reviewed journal of the American Cancer Society, the study found that exercise improved the oxygen capacity of patients and maintained levels of red blood cells during radiation treatment. In contrast, women who did not exercise experienced significant declines in their oxygen capacity. This is the first study to investigate the effect of exercise during treatment.
In the treatment of breast cancer, localized radiation therapy follows local surgical resection of the tumor. Its purpose is to destroy remaining cancer cells in and around the original tumor site. This combination is highly effective in this cancer’s treatment.
Side effects from radiation therapy are mild to moderate, ranging from a sunburn to an increased risk for cancer of the muscle or a sarcoma. Radiation also causes fatigue, anemia and depression soon after therapy is initiated. These symptoms are often associated with laboratory findings of reduced circulating red blood cells and hemoglobin, the means of oxygen transport in the body.
Studies have shown that physical rehabilitation following the completion of therapy effectively resolves the fatigue and anemia. However, to date there have been no studies investigating the effect of exercise on red blood cells. Led by Jacqueline S. Drouin, P.T., Ph.D. of the School of Health Professions and Studies at the University of Michigan-Flint, researchers compared the impact of exercise versus no exercise during radiotherapy on red blood cell levels and on maximum oxygen capacity, a measure of physical fitness, in 20 women with breast cancer.
The authors found that compared to women who did not regularly exercise, women who briskly walked 20-45 minutes three to five times a week during radiotherapy treatment did not experience a decline in levels of hemoglobin, red blood cells, and hematocrit. In the aerobic exercise group, mean red blood cell levels increased slightly while they declined in the sedentary group. Similarly, hemoglobin levels slightly increased while they fell in the sedentary group.
In addition, increases in these red blood cell measures also significantly correlated with increases in peak oxygen capacity.
“Study results support the potential for moderate aerobic exercise to be a safe, effective, and economical method for improving physical fitness and maintaining erythrocyte levels in females undergoing radiation treatment for breast cancer,” conclude the authors.