Radiation therapy for early
stage breast cancer carries a small, but real, risk of heart disease, new
The lifetime risk ranges
from 0.05% to 3.5%, depending on how the radiation was delivered and a woman's
overall risk for heart disease, the researchers report.
Women at greatest risk are
the ones receiving radiation on their left breast while lying on their back and
who also are at risk for heart disease.
Radiation of the left
breast ups the risk since that also exposes the heart to radiation, the study
The lowest risk is among
women receiving radiation for their right breast while lying face down. When
radiation is given on the right side, the heart is totally out of the field of
radiation, they noted.
Radiotherapy linked to heart disease risk
"Our findings confirm
that the radiation exposure associated with left-breast cancer radiotherapy is
associated with a generally small, increased risk of heart disease later in
life," said lead researcher David Brenner, a professor of radiation
biophysics at Columbia University Medical Centre, in New York City.
"Of course, that side
effect needs to be balanced against the fact that lumpectomy plus radiation is
of well-proven efficacy for treating early stage breast cancer," he said.
"All cancer therapies involve balancing benefits and risks."
In addition, the doses of
radiation used today are much lower than they were 20 years ago, so the heart
receives less exposure than it once did. "The risk of radiation-associated
heart disease is lower for patients treated now than it was in the past,"
For women who need
radiation for their left breast, the risk of developing heart disease can be
lessened by lying face down during treatment, the researchers found.
In addition, since women
most at risk of developing heart disease are those who are already at risk for
it, Brenner suggests they can reduce their risk by not smoking and keeping
blood pressure and cholesterol under control.
The report was published in
a research letter online in the journal JAMA Internal Medicine.
Dr Stephanie Bernik, chief
of surgical oncology at Lenox Hill Hospital in New York City, said it is known
that radiation to treat breast cancer increases the risk for heart disease.
When doctors do the
planning for the therapy, they try to limit the amount of radiation that
reaches the heart, she said. "You try to exclude the vital organs, but you
can't exclude them 100 percent on the left side."
However, the risk of heart
disease later on in life should not deter women from getting radiation therapy,
"If you are doing
breast conservation, radiation is part of the plan," she said. "The
recurrence rate is much too high without the radiation."
Heart disease related to
radiation treatment for breast cancer, however, can take anywhere from five to
20 years to develop, according to a recent study published in the New
England Journal of Medicine.
"There are a lot of
women who do not want to have breast conservation because of the radiation risk – they are concerned about the heart risk," said Dr Laura Kruper,
co-director of the Breast Oncology Program at the City of Hope Comprehensive
Cancer Centre in Duarte, California.
Kruper said there are newer
radiation therapy methods that reduce the risk. "We are really tailoring
patients' treatments," she said. "We have a lot of tools now where we
can offer women breast conservation and minimize their [heart] risk."
For the study, Brenner and
his colleagues examined the radiation treatment plans for 48 women with early
stage breast cancer seen in 2005 at New York University's department of
The investigators took into
account a variety of factors that could affect the chances of developing heart
disease after radiation treatment. These included the amount of radiation the
heart was exposed to, the patient's overall risk for heart disease, which
breast received radiation, whether the woman was lying face down or up during
treatment, and any heart problems.
Visit the American Cancer Society for more on breast cancer.
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