Exercise and cancer
Posted by Jonathan Chamberlain on May 3, 2009
Here is the text of an article on the benefits of exercise
From <http://www.medscape .com/news>Medscape Medical News
AACR 2009: Oncologists Should Recommend Exercise, But Not Supplements
April 23, 2009 (Denver, Colorado) Oncologists
should recommend exercise to cancer patients;
there is accumulating evidence to show that it
can improve both prognosis and quality of life,
according to Melinda Irwin, PhD, MPH, associate
professor of epidemiology and public health at
the Yale School of Medicine, in New Haven, Connecticut.
However, the evidence for supplements, such as
vitamins, minerals, and antioxidants, is
insufficient to make any science-based
recommendations on their use in cancer patients,
according to Cornelia Ulrich, MS, PhD, from the
Fred Hutchinson Cancer Center, University of Washington, in Seattle.
Both were speaking at a symposium on cancer
survivorship here at the American Association for
Cancer Research 100th Annual Meeting.
The best evidence for the benefits of exercise
comes from studies of breast cancer patients,
where it has been shown to reduce the risk for
relapse and mortality both from cancer and all
causes, Dr. Irwin said. There is also some
evidence of a similar benefit in prostate and
. “But I would strongly
hypothesize that the benefits from exercise
particularly for improving quality of life
would extend to all cancers,” she told Medscape .
In reviewing studies showing benefits from
exercise, Dr. Irwin cited 1 that her own group
published recently (J Clin Oncol.
2008:24;3958- 3964). The Health, Eating, Activity
and Lifestyle (HEAL) study of 933 breast cancer
patients showed that moderate-intensity physical
activity reduced the risk for death by 67% in
women who remained active 2 years after
diagnosis. This was both breast cancer mortality
and deaths from other causes, mostly
cardiovascular disease and diabetes, she added.
Other studies have suggested that exercise
reduces the risk for breast cancer mortality by
40% to 55%, “which is as much as standard treatments,” she said.
These studies have varied in their
recommendations for exercise some aimed for 90
minutes a week, others for 2 to 3 hours a week,
but the HEAL study showed a benefit from any
amount of exercise, she said. In some of the
studies, exercise started at diagnosis and
continued throughout and after the treatment.
“Any amount of exercise is better than none,” Dr. Irwin said.
“Oncologists are uniquely placed to recommend
exercise, and they have the perfect opportunity
to intervene as treatment is ending, because
patients are then eager to learn what else they
can do to help themselves,” she explained to Medscape Oncology.
“Of course, oncologists do not have the time to
discuss in detail,” Dr. Irwin
acknowledged, but the fact that the
recommendation is made by them, as cancer specialists, is “very valuable.”
“Our study showed that oncologist recommendation
is a strong predictor of uptake,” she said, “but
only half the patients in the study said that
their oncologist had mentioned exercise.”
A new development may make it possible soon for
oncologists in the United States to refer their
cancer patients to physical-fitness professionals
that are specifically trained for this work. The
American Cancer Society and the launched a
<http://www.acsm. org/Content/ NavigationMenu/ Certification/ Certifica% 20tionHome/ Health_Fitness_ and_.htm>Certified
Cancer Exercise Training course in January 2009.
“This would make it much easier for oncologists, ”
Dr. Irwin noted. “They could recommend exercise,
and then refer the patient to a trained professional. ”
Insufficient Evidence on Supplements
In contrast to exercise, the use of supplements
by cancer patients cannot be recommended at
present; there is insufficient evidence to make
science-based recommendations, Dr. Ulrich told the audience.
Some studies have suggested a benefit, but there
have also been some that suggested adverse
effects, she said. For example, 1 study suggested
that antioxidants interfere with in patients with head and neck cancer,
whereas another showed that the popular herbal
remedy St. John’s wort significantly reduced the
efficacy of irinotecan by interfering with its metabolism.
Despite the lack of evidence, supplements are
used by the majority of cancer patients, Dr.
Ulrich said. A recent review found that 64% to
81% of all adult cancer patients in the Untied
States take supplements, and 14% to 32% of them
started taking them after diagnosis. When asked
why, patients said they took supplements “in
order to feel better, to enhance their chance of
a cure, to retain a sense of control, and to ensure adequate nutrition.”
Another study found that 31% to 68% of cancer
patients and long-term survivors take supplements
but don’t tell their doctors, she said.
Dr. Irwin and Dr. Ulrich have disclosed no relevant financial relationships.
American Association for Cancer Research (AACR)
100th Annual Meeting. Symposium held April 21, 2009.