Exercise boosts chances of surviving breast cancer

May 25 2005

A new study is the first to produce evidence that exercise improves the prospects of beating a malignancy, and proves that being physically active boosts the odds that breast cancer patients will survive the disease.

The large, well-respected study of U.S. nurses, has found that breast cancer patients who walk or do other kinds of moderate exercise for three to five hours a week are about 50 percent less likely to die from the disease than sedentary women and adds credible support to sound evidence that healthy lifestyle factors such as eating well and exercising regularly provide significant health benefits.

The protection offered against cancer recurrences appears to be on a par with chemotherapy and even the newer hormonal and drug treatments.

Although physical activity is no substitute for medical treatment, and very often difficult for exhausted cancer patients, the researchers who conducted the study, and other experts in the field say the findings indicate breast cancer patients should try to exercise regularly after undergoing standard care to maximize their chances of surviving.

Michelle D. Holmes of the Harvard Medical School in Boston, who led the study, says women with breast cancer have little to lose and much to gain from exercise.

Because the benefits appear strongest for the most common form of breast cancer, and held true regardless of whether the cancer was diagnosed early or not, the findings are particularly interesting.

Debbie Saslow of the American Cancer Society says the results are exciting as many women want to know what they can do to aid recovery that doesn't involve drugs and side effects.

Previous research has already shown that regular exercise reduces the chances of developing many diseases, among them heart disease and various forms of cancer, including breast cancer and that exercise boosts breast cancer patients' sense of well-being and quality of life.

However this new study is the first to show that regular exercise reduces the death rate among women who have had breast cancer. Breast cancer affects approximately 211,000 U.S. women and kills about 40,000 each year, making it the most common cancer and second biggest cancer killer, after lung cancer, among women. The study comes hot on the heels of one last week that indicated for the first time that low-fat diets can reduce the risk of breast cancer recurrences.

Rachel Ballard-Barbash of the National Cancer Institute says there is a growing field of research on the role of lifestyle factors on cancer quality of life after diagnosis and on their potential effect on cancer survival and prognosis.

In the study, Holmes and her colleagues examined data collected on 2,987 women whose breast cancer was diagnosed between 1984 and 1998, and then provided detailed information about how much exercise they routinely got as part of the Nurses' Health Study.

The women were monitored through 2002 and the researchers found that any amount of exercise, even walking one hour a week, increased the odds of surviving. The degree of protection increased with the amount of activity up to about three to five hours a week.

Of the 959 women who got the least exercise, which was less than three hours a week, 110 died of breast cancer. In comparison, of the 335 women who got three to five hours of exercise a week, only 20 died of the disease.

The findings held up even after other factors which could confuse the analysis, such as smoking and eating habits were accounted for.

The benefit was greatest for women whose breast cancer was sensitive to the hormone estrogen, which is the most common form. Previous research had shown that exercise lowers the levels of estrogen, which can fuel the growth of breast cancer cells.

The results indicate that breast cancer patients who follow current government guidelines for physical activity could significantly boost their chances of surviving.

Saslow, speaking for the cancer society does caution that the findings should not be misinterpreted to mean that just because someone exercises they are guaranteed to survive, or that they should feel guilty or be blamed if they do not exercise.

As Anne McTiernan of the Fred Hutchinson Cancer Research Center in Seattle says many patients end up exercising less because they are worn out by the treatment.She says that women should try to avoid that and really try to exercise after their treatment, if possible, a few hours of brisk walking will do.

The study is published in the current issue of the Journal of the American Medical Association.