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 Radiation reduced the risk of death and of cancer
returning among women who had cancer cells detected in the cluster
of nodes under the arms after a mastectomy. The nodes are part of
the lymphatic system, a conduit for immune and other cells.
"It has been clear for some time that women in whom the disease has
not spread to the lymph nodes in the armpits will not benefit from
radiotherapy," Sarah Darby told Reuters Health.
"It's been unclear what the benefit is for women with one, two or
three positive lymph nodes," she said.
Darby is one of the study's authors from the Early Breast Cancer
Trialists' Collaborative Group at the University of Oxford in the
UK.
The new findings are based on data from over 8,000 women who were
randomly assigned to either receive radiation or not after having
one or both breasts removed because of cancer. The data were from 22
trials conducted between 1964 and 1986.
The researchers, who published their results in The Lancet, had
information about whether the women were diagnosed with breast
cancer again within about 10 years of receiving radiation. They also
knew whether the women had died by the start of 2009.
They confirmed what had been known - that radiation did not offer
any benefits for women who had no lymph nodes test positive for
cancer after their mastectomy.
But for women who had one to three lymph nodes test positive after
their breasts were removed, they did find a noticeable difference in
cancer recurrence and death.
For example, women with positive lymph nodes had about a 46 percent
risk of their breast cancer returning during the 10 years after
their breasts were removed. That risk fell to about 34 percent over
10 years among women who received radiation.
Similarly, about 47 percent of the women who did not receive
radiation died of breast cancer by the start of 2009. That compared
to about 37 percent of women who received radiation.
Women who received radiation were also less likely to die from any
cause, compared to those who did not get radiation.
The benefits of radiation remained even among women who received
other treatments, such as chemotherapy.
"This actually will confirm a lot of what people started to think
about," Dr. Alphonse Taghian told Reuters Health.
He wasn't involved in the new study but is co-director of the Breast
Cancer Research Program and chief of breast radiation oncology at
Massachusetts General Hospital in Boston. He also teaches at Harvard
Medical School.
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"My sense is that there is a majority of physician oncologists who
would use post-mastectomy radiation in patients with one to three
positive lymph nodes," Taghian said.
"There will still be cases that we'll agonize about and it's not
really clear cut, but there is no doubt that this study will make an
impact on how people think about the one to three positive lymph
nodes," he said.
Most professional guidelines do not recommend radiation for women
with one to three lymph nodes that test positive for cancer, Darby
said.
"I hope people will review the guidelines," she said. "I would
certainly expect the guidelines to change."
Due to the age of the data included in the study, however, there are
some caveats.
Specifically, the women included in this analysis had their lymph
nodes sampled or completely removed to see how many contained
cancer. Those procedures are not commonly used now.
Also, Taghian said, it's also important for people to know that
while radiation can cause heart problems or other cancers, the
technology has improved.
"We are more precise," he said. "We are able to protect
tremendously the tissue which doesn't need to be exposed to
radiation and we have a better understanding and knowledge of the
biology of the tumor. This should reduce the risk of having major
complications."
Dr. Philip Poortmans wrote in an accompanying editorial that the
results of the new analysis "clearly confirm" that post-mastectomy
radiation should be considered for patients with one to three lymph
nodes that test positive for cancer.
He is with the Department of Radiation Oncology at the Institute
Verbeeten in Tilburg, Netherlands.
Darby said it's important for women to talk with their doctors about
their treatment options.
"Breast cancer is a very complicated disease," she said. "In each
individual case it would be very hard for the patient to know what's
best. I would counsel women to talk about it with their
oncologists." ___
Source: http://bit.ly/NOENqw and
http://bit.ly/QbL4yr
The Lancet, online March 19, 2014.
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