People who have survived cancer and are dealing with side effects of treatment, financial worries, and psychological issues surely have other things on their mind than whether or not they're eating enough fruits and vegetables. So it's not terribly shocking that cancer survivors aren't doing much better than the general population at staying at a healthy weight, getting enough exercise, avoiding tobacco use, and eating a healthful diet.
In fact, new information from the American Cancer Society shows that only about 1 in 20 survivors is meeting all three lifestyle recommendations: accumulating 150 minutes of moderate or 60 minutes of vigorous exercise a week, eating five servings of fruits and vegetables every day, and eschewing tobacco. This isn't just an American problem; last week, a study in Cancer revealed that fewer than 22 percent of Canadian cancer survivors were physically active, while more than 18 percent were obese.
News of the Canadian study kicked up a storm over on the New York Times's Well blog, where some readers said the report blamed the victim. But none of this research (nor the coverage of it) suggests that cancer survivors somehow brought the disease upon themselves. Even if people had the same habits before they got sick, which wasn't investigated, cancer is rarely attributable to a single cause.
The studies didn't ask why survivors aren't sticking to the recommendations, but you can imagine many reasons: Some might still be recovering from treatments that cause fatigue or weight gain or reduced heart or lung function; others are on drugs (like aromatase inhibitors for breast cancer) that cause muscle fatigue. Let alone the stress that may cause some people to smoke or overeat.
But clearly, the message isn't getting out that there are real benefits to be gained by adhering to these recommendations. The positive impact on well-being and daily functioning is well established. The ACS study found that the more health-behavior recommendations the survivors followed, the better they rated their health-related quality of life. (I wrote a few years ago about the benefits of exercise for people with many chronic diseases, including cancer.) People who exercise regularly seem to tolerate treatment better, have fewer side effects, and just plain feel better than those who don't, says Jeff Meyerhardt, a gastrointestinal oncologist at Dana-Farber Cancer Institute in Boston. Exercise is even helpful in reducing fatigue.
Less clear is whether lifestyle measures can actually cut the chances that the cancer will recur, a field of research that is relatively new but appears promising. "We used to think that lifestyle was only important in the prevention of cancer," says Kerry Courneya, who researches the links between physical activity and cancer at the University of Alberta and is an author of both recent studies. (We've previously published a nine-point action plan for preventing cancer.) "But lifestyle behaviors may be just as important, if not more important, after a diagnosis." Diet appears to have some effects, at least in certain cancers; one trial found that a low-fat diet may protect against a recurrence, either because of the fat in the diet or the subsequent weight loss (though another study found that eating more than five servings of fruits and veggies didn't bring any additional benefit in breast cancer recurrence). Last year, Meyerhardt and other researchers showed that a typical western diet might be associated with a greater risk of recurrence in colorectal cancer survivors.
Evidence that exercise can make a difference is based on observational studies only. One found that breast cancer survivors who walked between three and five hours a week lived longer than those who were inactive. But Courneya is now recruiting breast cancer survivors for a randomized, controlled trial that will look at whether an intense, supervised exercise program affects recurrence rates. Whatever his findings, the other payoffs of a healthful lifestyle mean that trying to change certainly can't hurt.