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Exercise: The New Cancer Treatment

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“Mr. Smith, you’re scheduled for your first chemotherapy appointment on Tuesday. Please come in 90 minutes early so that you can work with your exercise physiologist on your personalized pre-chemo workout. Don’t worry—it’s covered by insurance.”

Welcome to a new field—exercise oncology. While the above scenario is admittedly futuristic for most people diagnosed with cancer—especially that insurance part—it’s actually showing promise in clinical studies now taking place in Europe, Australia and the US.

Traditionally, cancer patients have been encouraged to get plenty of rest. But what they may really need is a treadmill, a bike or a pool—maybe weights, too. Yes, even during the treatment—as tough as that may be sometimes.

Why? There’s growing evidence that for many cancers, the right kind of exercise may not only minimize the side effects of chemo, radiation and surgery—but also make the treatments themselves more effective.

“In the future,” says Mark Dewhirst, DVM, PhD, a professor of radiation oncology at Duke University School of Medicine and an expert in the new field, “people with cancer may receive a prescription that tells them what dose of exercise they should add to their cancer treatment plan.”

But anyone with cancer can, with a doctor’s go-ahead, exercise today. Here’s what you need to know about the exciting new findings on fighting cancer with exercise.

HOW EXERCISE MESSES WITH CANCER…AND SUPPORTS RECOVERY

You’ve probably already heard that regular exercise can help prevent cancer in healthy people.

But that’s just the beginning.

If you’re a cancer survivor, there’s good evidence that exercise helps prevent recurrence. “People with breast, colorectal or prostate cancer who exercise end up doing better and surviving longer than people who don’t get exercise,” says Dr. Dewhirst. “The American Cancer Society and National Cancer Institute suggest that brisk walking for two-and-a-half hours each week may be enough.”

If you have cancer, an exercise program can support your health so that you are strong enough for treatments. People who exercise during their treatment phase often have higher physical and social functioning—and less fatigue and depression—than people who don’t exercise. This is partly because exercise helps counteract cardiovascular side effects of treatment. And if your exercise regimen means you have the strength to finish your chemotherapy or undergo surgery, that alone can be lifesaving.

But exercise may also directly help you fight cancer. One way it does this is simply by improving circulation. Aerobic exercise such as brisk walking gets oxygen-rich blood moving to our muscles, brain and other tissue…but it also improves blood flow to cancerous tumors. “That may sound like a bad thing,” says Dr. Dewhirst, “but it’s not. One of the major problems with cancer treatment is that chemotherapy drugs don’t penetrate the tumor easily because blood flow to the cancer cells is so abnormal. Drugs can’t work very well because they have a hard time reaching the cancer cells. But moderate exercise can double or even triple the blood flow, allowing the drug to be much more effective in targeting the cancer. Because cancer cells are living in oxygen-deprived conditions, they build up defense mechanisms that make them resistant to drugs and radiation.” Improving blood flow brings more oxygen to those cancer cells, making them healthier and more easy to kill. One hypothesis now being tested—exercising within an hour before or after chemotherapy—may be the most effective approach to maximizing treatment.

Another benefit: Even moderate aerobic exercise reduces your body’s need to produce insulin, which in turn reduces inflammation. Those modifications affect the host milieu…the environment that had been nurturing the cancer cells. When the environment becomes less comfortable for the cancer cells, it’s easier for the body to kill them.

Vigorous exercise, the kind that gets you sweating, appears to stimulate adrenalin, which activates the body’s own cancer-destroying natural killer immune cells. (That may be one reason high-intensity exercise is linked with prevention of prostate cancer.)

The molecular composition of a particular cancer may also greatly influence the effects of exercise, just as it does for pharmaceutical treatments. For example, one observational study found that about three hours of moderate-intensity exercise per week (in this case, walking at about three miles per hour) was associated with a 50% reduction in risk for death in women with hormone–sensitive breast cancer…but only a 9% reduction in women whose tumors were not sensitive to hormones.

Nor is every cancer patient a candidate for an exercise prescription. Some cancer drugs can cause heart rhythm problems, which exercise can make worse, for example. If exercise leads to weight loss, that can be a problem for some people, too. And people with bone cancer, who are at risk for fractures, have to be careful about falls.

EXERCISE AND THE CANCER PATIENT

There’s still much to learn before oncologists routinely prescribe specific exercise protocols.  “At this point, we can’t say with any certainty how much exercise to get and at what intensity,” says Dr. Dewhirst.

But we do know enough to say this—the proven benefits of exercise are already so strong that anyone with cancer should discuss how to start an exercise program tailored to his or her needs. If you are diagnosed with cancer, are undergoing treatment or have recently completed treatment, ask your cancer team if it’s safe for you to start an exercise program. You may want to ask to work with an exercise physiologist to help you develop a program that’s appropriate for your needs. (If you’ve just been diagnosed, exercise should be part of your cancer prehab.)

Dr. Dewhirst suggests that people with cancer follow the recommendations from the American Cancer Society, which state that adults should get 150 minutes of moderate exercise or 75 minutes of vigorous exercise each week. That’s the kind of exercise routine that has been shown—in general—to help prevent recurrence.

Interested in what such programs actually look like? This documentary by Catalyst, a television series from the Australian Broadcasting Corporation, takes a deep dive into how one such program works for patients.

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Source: Mark Dewhirst, DVM, PhD, professor of radiation oncology, Duke University School of Medicine, Durham, North Carolina. He would like to acknowledge the mentoring he has gotten from Lee Jones, PhD, who runs the exercise oncology program at Memorial Sloan Kettering Cancer Center in New York City. Date: May 30, 2016 Publication: Bottom Line Health
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