The vast majority of Canadian cancer survivors are physically inactive and more than a half are overweight and obese, putting themselves at risk of having their cancers come back, new research showed.

Kerry S. Courneya, PhD., University of Alberta, Edmonton, lead author of the study, used data from the 2005 Canadian Community Health Survey to gain insight into the everyday life of people who have survived cancer. The survey included 114,355 adults with details on medical history, weight and height and the nature of the survivor’s leisure time activity.

The study found that fewer than 22 per cent of these survivors were physically active enough to avoid an increased risk of disease returning. More than 18 per cent were obese, and another 34 per cent were overweight.

In Canada, there were more than one million survivors of non-skin cancers in 2005, including 223,000 breast, 147,000 prostate and 100,000 colorectal cancer survivors.

The findings are the more worrisome, as many cancers are linked with obesity and a lack of exercise. Several studies have suggested that physical activity and losing weight may help prevent cancer recurrence and improve survival odds.

“These findings tell us that we need to look at ways to better support cancer survivors to become more active and to maintain a healthy body weight. We know that physical inactivity and obesity are risk factors for developing cancer. These are also risk factors for the recurrence of cancer. Lifestyle is just as important after diagnosis,” Courneya said, according to Reuters.

Courneya concludes there should be interventions with cancer survivors to increase their physical activity and get them to eat a healthier diet.

The researchers defined someone as physically active if they walked at least an hour a day or did the equivalent in swimming, cycling or some other activities. Inactive people walked or exercised less than 30 minutes a day.

Kevin Stein, director of Quality of Life Research at the American Cancer Society commented on the findings: “This is an important finding to underscore the fact that cancer survivors need to pay attention to their health. You've dodged a bullet for the time being, but cancer survivors are actually at an increased risk for a number of health conditions, including cancer recurrence. There is a teachable moment when someone is diagnosed. It's the perfect opportunity to say, 'We all need to eat healthy and exercise, but it's even more important for you as a cancer survivor.”

The study will appear in the June 1 issue of the journal Cancer.