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You may have heard that moderate intensity exercise - even brisk walking - may be linked to a 37 percent reduction in risk of death over time for colon cancer survivors, according to a surprising new study. More good news is that experts believe the results may apply to those with other types of cancer as well.
"I think a lot of people were just gobsmacked when they saw these data, because these data are as good as many of the drugs that are out there," said Kerry S. Courneya, a co-author of the study and a professor and Canada research chair in physical activity and cancer at the University of Alberta in Edmonton, Canada. "I think the surprise was just more the magnitude of the benefit."
The research, which was published June 1 in the New England Journal of Medicine, is a large, randomized, placebo-controlled trial - the gold standard for determining if something works. During roughly an eight-year period, 90.3 percent of exercisers survived compared with 83.2 percent of those who were in a general health education program.
We asked experts what people should know about this new research and how people who've had cancer - especially those who might still be experiencing fatigue, nausea and other side effects from treatment - can reap the potential benefits.
• How much exercise is beneficial?
In the new study, researchers didn't just tell patients to exercise. People with Stage 2 or Stage 3 colon cancer (who had already completed surgery and chemotherapy two to six months earlier, and also passed a treadmill test) were given a structured exercise program that pushed them to reach certain exertion targets, almost as if they were in physical therapy. That made a difference, noted Rebecca Wong, a professor in the radiation oncology department at the University of Toronto and a co-author of the study, because it provided motivation and goals that enabled people to stick with exercise over time.
In all, 445 people were put on the structured exercise program for three years and another 444 patients were simply advised that exercise would help their prognosis. In the structured program, people hit their targets mainly by brisk walking, which is considered moderate intensity activity, though some were able to do higher-intensity activities such as jogging, swimming, biking, playing pickleball or tennis. But the benefit isn't just from having a structured regimen, Wong said. It's having one you stick with for the long haul. "It's a lifestyle change," Wong said. "It's not so much, do this for three years and you can go back and sit on the couch."
And the reduced risk was not just for colon cancer. Patients in the structured exercise group also were less likely to develop new primary cancers, indicating there is potentially a protective effect for other cancers as well.
• How should cancer patients exercise?
For cancer survivors, the American College of Sports Medicine recommends starting slowly and building up to at least 150 minutes of aerobic activity a week, either moderate-intensity activity such as walking, light cycling, yoga, tai chi or water exercise, or 75 minutes a week of vigorous activity such as brisk walking, singles tennis or hiking hills - or a combination of both. They also recommend some strength and resistance exercises such as weight training two to three times per week, suggesting 6 to 15 reps using weights, resistance bands, weight machines or your own body, doing things such as kitchen counter push-ups or chair squats.
Of course, if you have cancer or have recently completed treatment, the last thing you might want to hear is that you need to work out. Given how physically arduous cancer treatment can be, it's important to note that the new study was conducted in patients who had completed active treatment for their colon cancer, said Sharlene Gill, a professor of medicine at the University of British Columbia and a co-author of the study.
The findings "can't be extrapolated to those patients who are on active treatment and are managing symptoms and side effects, but we believe there would be a quality of life benefit," Gill said.
For those people, exercise needs to be matched with capacity. The "general rule is that any activity is better than no activity, and it should be moderate but not intense," she said.
Some say their fatigue is not too bad in the morning so they can try to exercise early in the day, while others say nausea is worse after they eat so they can try to exercise before they eat, Courneya said. If pain or nausea are too severe, they should rest. But he added that exercise has been shown to help with these symptoms, especially fatigue and pain, so if possible, patients could try to push through it.
"Patients will need to judge their own side effects and work around them," Courneya said.
"We recommend that patients undergoing treatment do activity as they are able, but definitely acknowledging the challenges, especially around the time of treatments," Deborah Manst, an oncogeneralist at the University of Illinois Cancer Center and a clinical assistant professor in family and community medicine, wrote in an email. She was not involved with the study.
At her cancer center, an Exercise Physiology Group can help develop exercise plans for patients with limitations, she said. Manst said cancer patients should ask their oncologist about structured exercise programs. "If such a program is available that is a great idea, or they can look into community support organizations or personal trainers that provide similar services," she said.
The new study was groundbreaking because while there was already evidence that physical activity reduces one's risk of developing certain cancers - for colon cancer, the risk falls by almost 20 percent for those who are active - there wasn't as much evidence regarding post-diagnosis outcomes, said Scherezade Mama, a researcher of cancer prevention at the University of Texas MD Anderson Cancer Center, who was not involved in the study.
"Physical activity posttreatment reduces risk of recurrence and increases survival," Mama said. "This is big and the evidence our field has been waiting for."
Adeel Khan, a hematologist/oncologist and an assistant professor of medicine and public health at the University of Texas Southwestern Medical Center, wrote in an email that the benefits of physical activity include supporting muscle mass, reducing fatigue, and aiding with symptoms such as shortness of breath and mobility, as well as improved sleep and psychological benefits, but he notes that more research is needed to confirm that exercise can help survival after treatment.
"The benefits centering on quality of life and wellness metrics are clear," he wrote. "The reasons for its success are believed to be the same for non-cancer patients - simply put, exercise keeps people physiologically healthier."