Exercise Helps Prevent Breast Cancer

Exercise may help prevent breast cancer, and help those who
do get it cope, two new studies show.

The first study, based on interviews with 15,000 women, shows that women who
get more than six hours of strenuous exercise a week, and have no family
history of breast cancer, may be 23% less likely to develop the disease than
women who don't exercise at all.

The second study shows a 12-week group exercise program may boost mood and
physical function in women with early-stage breast cancer.

The researchers don't promise exercise will prevent breast cancer, or blame
breast cancer on a lack of exercise. Many factors affect cancer risk.

But, they do report exercise appeared to have benefits in protecting against
cancer for women of all ages.

"We have found that exercise likely offers protection against breast
cancer regardless of a woman's stage in life," researcher Brian Sprague, of
the University of Wisconsin Paul P. Carbone Comprehensive Cancer Center, says
in an American Association for Cancer Research (AACR) news release.

"The take-home message for women should be that it is never too late to
begin exercising," Sprague says.

Breast Cancer Prevention Study

The study by Sprague, assistant professor Amy Trentham-Dietz, PhD, also of
the Carbone cancer center, and others, appears in Cancer Epidemiology
Biomarkers & Prevention

For the study, the researchers interviewed more than 15,000 women in
Massachusetts, New Hampshire, and Wisconsin by telephone.

Those interviewed included 6,391 breast cancer patients and 7,630 women
without breast cancer. The women were 20-69 years old, roughly split between
women 49 and under, those in their 50s, and those in their 60s.

Family History of Breast Cancer

Most had no family history of breast cancer, including the women with breast
cancer themselves. While family history increases breast cancer risk, most
patients don't have a family history of the disease.

During the 40-minute phone interview, the women noted whether they had
participated in the following activities at some point in their lives since age
14: jogging/running, bicycling, calisthenics/aerobics/dance, racquet sports,
swimming, walking/hiking for exercise, or other strenuous individual or team

Most women, whether or not they had breast cancer, reported getting up to
three hours of weekly strenuous exercise at some point since age 14.

But 461 women without breast cancer, and 332 with breast cancer, said they
had exercised strenuously for more than six hours weekly at some point since
age 14 -- typically when they were in their teens and early 20s.

23% Less Likely

The women who reported getting more than six weekly hours of strenuous
recreational physical activity were 23% less likely to have breast cancer,
compared to sedentary women, the study shows.

Exercise appeared to benefit women, regardless of age.

But the benefits were only seen in those with no family history of breast

The results held after adjusting for other breast cancer risk factors.

The study doesn't prove that exercise single-handedly prevented breast
cancer or show how exercise may lower breast cancer risk.

The effects of exercise on hormones and weight may help, the researchers

They note that they don't know if the women accurately recalled their
workout habits.

Exercise for Breast Cancer Patients

The second study comes from researchers including Nanette Mutrie, PhD,
professor of exercise and sport psychology at the University of Strathclyde in
Glasgow, Scotland.

They studied 203 women with early-stage breast cancer who were 51 years old,
on average, and hadn't been exercising.

The patients had had breast cancer surgery (lumpectomy or mastectomy) and
were getting chemotheapy and/or radiation therapy to help prevent their
cancer's return.

First, the women completed surveys about their mood and quality of life.
They also took a 12-minute walking test and had their shoulder mobility

Next, Mutrie's team split the women into two groups.

One group participated in a 12-week group exercise program. The other group
wasn't asked to exercise.

Group Exercise Program

The women in the exercise group met twice weekly for 45-minute exercise
classes. They were also encouraged to work out once a week on their own at

For the first six weeks of their 12-week program, the exercise group
gathered after classes to discuss topics such as setting goals and the health
benefits of exercise.

Both groups of women repeated the psychological and physical tests at the
end of the 12-week program and again six months later.

Those in the exercise group had improved their scores on the physical tests
and also reported being in a better mood and coping better with breast cancer.
Those benefits generally held at the six-month follow-up.B

It's not clear how much of the benefits were due to the workouts or to the
social aspect of group exercise.

However, the researchers say doctors "should encourage activity for
patients with cancer," and that future studies should also investigate
home-based exercise programs, which may be more convenient for some

The study appears in BMJ Online First. BMJ was formerly called the
British Medical Journal.


By Miranda Hitti
Reviewed by Louise Chang
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