Taken from: http://www.canada.com/globaltv/national/story.html?id=7754a09a-2cb6-4d76-9dbd-b427eab27483&k=58494


The vast majority of Canadian cancer survivors are physically inactive and more than half are overweight or obese, increasing the risk of cancer coming back and an early death, a major study shows.

Those with the most to gain from exercise -- breast and colon cancer survivors -- are the least likely to be active.

The University of Alberta-led study, published in the most recent issue of the journal Cancer, shows that a cancer diagnosis "does not appear to be prompting significant behaviour change."

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.

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.

Evidence is mounting that the heavier and less active a patient is, the greater the likelihood of the cancer recurring and the lower the odds of survival, independent of the type of cancer, stage of disease or treatment, says Kerry Courneya, professor and Canada Research Chair in physical activity and cancer at the University of Alberta.

Exercise reduces insulin, which tends to make cells divide and grow more quickly. It also lowers estrogen and testosterone, the sex hormones that certain cancers, including breast, endometrial and prostate cancers, rely on to survive.

Overall, cancer survivors are no better and no worse than the general population when it comes to obesity and inactivity, the study shows.

"People have talked about how cancer might be a teachable moment where people might be motivated to change their behaviour and improve their health," Courneya says.

Recent studies show a breast cancer survivor who does the equivalent of walking three to five hours per week cuts her risk of dying from cancer by half. Colorectal patients who exercise have 40- to 50-per-cent lower risk of disease recurrence or death than those who don't exercise.

Courneya's team relied on data from the 2005 Canadian Community Health Survey, consisting of interviews of 114,355 adults.

Fewer than 22 per cent of cancer survivors reported being active, with the lowest rates reported by female colorectal cancer survivors (13.8 per cent), breast cancer survivors (16.6 per cent) and male colorectal cancer survivors (20.1 per cent). Obese breast cancer survivors were less likely to be exercising than obese women without a history of the disease. Women cancer survivors were less likely to be active than male survivors.

Courneya says most oncologists are not recommending weight loss or exercise to cancer patients. Their focus instead tends to be on treatment options and how patients cope with side-effects.

She says exercise can be the furthest thing from a cancer patient's mind. "During treatments, the look on a cancer patient's face when you approach them about exercise is, it's the last thing they thought you were going to ask them to do.

"They've just been told they're going to go on chemotherapy, they're going to have some serious side-effects, and by the way we recommend that you exercise."