Exercise may prevent some cancers, help cancer patients feel better, and can be an important part of their treatment plan, too.
Exercise helps cancer patients cope and boosts mood when their diagnosis and treatment causes feelings of being overwhelmed and depression. In fact, the National Cancer Institute (NCI) recommends exercise to boost the quality of life for cancer patients and cancer survivors.
There’s growing evidence regular workouts might fight cancer directly, too, by lowering the risk for malignancies and possibly reducing the rate of recurrences. Preliminary research also suggests exercise may play a role in cancer treatment.
Numerous studies have found a link between physical activity and cancer. Being physically active — getting between four and seven hours a week of moderate-to-vigorous intensity exercise — appears to reduce the risk of certain cancers, especially colon and breast malignancies. Some of the strongest evidence indicates people who exercise regularly are 30 to 40 percent less likely to develop colon cancer, compared to sedentary folks. What’s more, if a person has been treated for colon cancer, research by Dana-Farber and Harvard University scientists concluded exercise may reduce the odds they will have a recurrence of the disease.
Around 50 epidemiological studies suggest the risk for developing breast cancer is about 20 percent lower in physically active women, according to NCI scientists.
Exactly how exercise may prevent breast cancer isn’t known, but researchers are studying several possibilities. For example, some scientists think physical activity may prevent breast tumors from developing by lowering hormone levels, particularly in premenopausal women. Regular exercise can reduce levels of insulin and insulin-like growth factor I (IGF-I), too. This might boost an immune response and stop cancer cells from growing. In addition, exercise helps keep weight under control, and excess body fat is known to be a risk factor for breast cancer.
Brad Behnke, PhD, associate professor of exercise physiology at Kansas State University, and colleagues are documenting how exercise may help treat certain kinds of cancers by increasing oxygen levels in the body. So far, in animal studies, they’ve found this approach may make some prostate malignancies more sensitive to certain cancer therapies, especially radiation.
Although his research is preliminary and doesn’t apply to all kinds of malignancies, Behnke hopes it may demonstrate ways exercise can help directly fight cancer. “Exercise is often prescribed to improve the side effects of cancer treatment, but what exercise is doing within the tumor itself is likely beneficial as well,” he said. “Exercise is a type of therapy that benefits multiple systems in the body, and may permanently alter the environment within the tumor."
Cancer patients should talk to their healthcare team about how much exercise, and what kind, is best for their particular diagnosis and the treatment that they are undergoing. The American College of Sports Medicine, working with cancer experts from the NCI and other medical centers, developed guidelines to allow cancer patients and their doctors to map out effective, safe exercise and physical activity programs — both for those who are currently undergoing cancer treatment and those who have completed their therapies.
“Our hope is that there will be more conversations about the need for formalized exercise programs for patients during and right after treatment-programs that will be the cancer equivalent to cardiac rehab,” said Kathryn Schmitz, MD, of the University of Pennsylvania’s Abramson Cancer Center, lead author of the guidelines. She added that benefits of exercise are well documented for many cancers and are especially beneficial in treating fatigue and physical functioning.
While research continues on the specific ways exercise may prevent and help beat cancer, the evidence linking regular physical activity with improved quality of life while cancer patients undergo active treatment, as well as for those who have completed their radiation and chemotherapy, “is incredibly strong,” said Rachel Ballard-Barbash, MD, of NCI’s Division of Cancer Control and Population Sciences.
The NCI offers information on how exercise can help prevent cancer and benefit cancer patients being treated for the disease.
July 23, 2015
Christopher Nystuen, MD, MBA