Exercise may reduce risk of cancer recurrence and improve survival rates

Updated guidelines for physicians include evidence-based exercise "prescriptions" for patients with different types of cancer.

Exercise might lower the risk of cancer recurrence and improve survival rates, according to the latest guidelines released today about exercise and cancer.

"There's some provocative data coming out that says patients who exercise during and after treatment might actually even lower their risk of the disease coming back, which of course, is the most important outcome for a cancer patient," said U of A cancer researcher Kerry Courneya, Canada Research Chair in Physical Activity and Cancer and co-author of the 2019 Exercise Guidelines for Cancer Survivors.

Courneya said a string of reviews concluded that exercise prevents at least seven types of cancer from recurring, and that there is substantial evidence suggesting exercise is associated with improved cancer-specific survival in patients with breast, colon and prostate cancer.

"It's definitely the most compelling outcome for oncologists and patients, and it's definitely the finding that would drive exercise motivation, and also drive the implementation of exercise into clinical cancer care," he said.

Courneya said the guidelines are an update of the American College of Sports Medicine's first effort from 2010, which concluded that cancer survivors could safely engage in enough exercise training to improve physical fitness and restore physical functioning, enhance quality of life and mitigate cancer-related fatigue.

"What you'll see from reading those guidelines is the evidence has grown exponentially over this last decade," he said.

Rather than a general recommendation to be physically active, the new guidelines provide prescriptions related to the type, frequency, intensity and duration of exercise for cancer survivors suffering from a list of eight common, long-term effects of cancer and cancer treatment, Courneya noted.

For example, the guidelines suggest a dose of moderate-intensity aerobic training three times per week for 12 weeks, or twice weekly combined aerobic and resistance training for six to 12 weeks, can significantly reduce anxiety in cancer survivors during and after treatment. The cancers covered by this prescription include breast, prostate, colorectal, gynecological, head and neck, and hematological.

Symptoms of fatigue, which can last indefinitely after cancer treatment, can be greatly reduced by bouts of vigorous exercise, which could include combinations of resistance and aerobic training lasting 30 minutes or more. In this case, however, the evidence only currently exists for breast and prostate cancer patients.

Another new recommendation from the guidelines advises that exercise has been found safe for both colorectal and lung cancer patients.

And though exercise has been found to be largely beneficial for cancer survivors, Courneya said the guidelines do offer a warning in some cases. For instance, he said there is no evidence yet that exercise improves cognitive dysfunction associated with some chemotherapy treatments.

"The same can be said for peripheral neuropathy, which is numbness and tingling in the hands and fingers," he said. "Cancer patients do have issues with balance and numbness and tingling, so there are risks of falling."

Courneya added that high-intensity or high-impact exercise puts patients with metastatic cancer that has spread to the bones at risk of bone fractures.

But where exercise is recommended, Courneya said cancer patients should be active, especially considering the guidelines also show that exercise facilitates chemotherapy completion in breast cancer patients.

"Obviously this is a really an important outcome for cancer patients, because if you're doing high-intensity exercise and it's interfering with your ability to complete chemotherapy, that would be a setback," he said. "But there's been a couple studies we report now that actually show that exercise improves chemotherapy completion rates."