A brisk walk a few times a week could help keep colon cancer away, study suggests

James Smith woke up from a colonoscopy to be told devastating news. At 59, he was diagnosed with colon cancer. Doctors found a mass so large it completely blocked their view of the rest of his colon. Smith said he was shocked.

"It was hard, it was a hard diagnosis," he said. "It was hard to believe it was actually happening."

Smith underwent surgery and four rounds of chemotherapy. When his doctors suggested he join a study to examine regular exercise and its possible role in preventing cancer recurrence, he said yes. He was concerned — through the course of his treatment he had lost about 26 kilograms, as well as muscle mass. But he joined, anyway.

"At the beginning it was difficult, I won't deny. It was like, 'How am I going to do all this?'"

Though he wasn't included in the final study, he ended up finding the program helped him gain a sense of control over the cancer and his treatments. Smith is now cancer-free and his prognosis is good, he says.

The study, which was published in the New England Journal of Medicine on Sunday, found that for patients with colon cancer, structured exercise did make a difference. Seven years after being diagnosed, 90 per cent of the patients who took part in the structured exercise program over a three-year period were still living. In the group that had only received an informational pamphlet, 83 per cent of participants were still alive.

The researchers don't know exactly why the program had such an impact. But the findings could have significant future implications for how patients with colon cancer, one of the most common cancers, receive treatment.

The study enrolled 889 patients from 55 hospitals in Canada, Australia and the United Kingdom. The clinical trial focused on high-risk stages 2 and 3 colon cancer patients who had received surgery and chemotherapy. Half of the group was given the traditional take-home pamphlet recommending diet and exercise and the other half was prescribed a structured exercise program for three years. The study lasted for 15 years, with about half of the participants joining in the beginning and the rest later on.

Patients in the exercise group were assigned a physiotherapist or a personal trainer to check in with at least once a month. But they were free to decide what kind of exercise they wanted to do. They just had to do it for up to 45 minutes, depending on the type, three times a week. For Smith, that meant walking briskly on a treadmill. Other participants biked, swam or hit the gym. In each case, the exercise had to include a sustained, elevated heart rate. (They didn't specify a figure.)

"If someone saw you walking, they would think you are late for an appointment," said Kerry Courneya, a kinesiology professor at the University of Alberta and the lead author of the study.

Courneya launched the research because previous studies had hinted at the benefits of exercise, but nothing was definitive enough to convince doctors. The exercise program is not meant to replace traditional treatments, like surgery and chemotherapy, but is meant to enhance them.

"There was a lot of skepticism with the observational studies, and many health-care providers and oncologists felt like they didn't act on them because they were methodologically limited."

Researchers found differences in cancer recurrence, as well. Eighty per cent of the exercise group was cancer-free five years after their diagnosis, compared with about 74 per cent in the group that received the pamphlet. Colon cancer typically recurs in about 30 to 40 per cent of patients.

Dr. Chris Booth is a senior author of the study and an oncologist at Queen's University in Kingston. Booth suggests that when combined with traditional treatments, the benefits of the prescribed exercise program are comparable to some chemo drugs.

"There are treatments we use every day that have much smaller benefits and some of the treatments we think are important have benefits that are comparable to this [exercise]."

Dr. Sami Chadi is a colorectal surgeon and clinician investigator at the Princess Margaret Cancer Centre, part of Toronto's University Health Network. He was not involved in the research, and already encourages his patients to exercise. But he says he plans to use this research to help convince his patients to follow a structured exercise routine.

"I don't think there is any question about it. I think a structured exercise program after surgery and after treatment is absolutely necessary, so we should be strongly recommending it as strongly as we recommend chemotherapy to our Stage 3 patients."

The researchers don't know why exactly the exercise program impacted the recurrence and improved survival. They do know it wasn't about weight loss or improved cardiovascular function, because there was no significant change in either factor during the study. Dr. Booth describes it as a mystery that he aims to solve.

"We banked blood on all the patients," he said. "In the next couple of years, we will be doing detailed biomarker analysis to try and understand what it is about exercise that is reducing the risk of cancer recurrence."

WATCH | Dr. Booth on the study's findings:

Dr. Christopher Booth, oncologist from Queen's University, discusses the results of his study that looked at the impact of an exercise program on people with colon cancer.

In the meantime, he says this study should give enough evidence to convince patients, doctors and governments that structured exercise programs should be an important part in their arsenal to reduce the risk of a recurrence of colon cancer.

As for Smith, it's been nearly five years since his diagnosis. He is doing well and still exercising and playing hockey in Edmonton. Recurrence is still something he worries about, but he's thrilled to hear the results of the research, calling them fantastic.

"It gives me [that] extra knowing that my exercise and my well-being is helping my chances of not getting colon cancer or the recurrence of cancer again."