Heading Breast Cancer Off at the Pass
Dec. 20, 2000 -- Sometimes choosing a treatment can be the hardest part of
receiving a diagnosis. That's certainly true for the more than 180,000 women
diagnosed with breast cancer each year. For those whose family history or a
genetic defect make them more likely to get the disease, one option is even
more daunting: whether to remove one or both breasts to stop the disease before
it starts, a mastectomy.
In a follow-up of women who had mastectomies to prevent cancer,
Dutch researchers say that doing the surgery before cancer strikes
significantly reduces incidence of the disease in those who are at high risk.
However, other doctors say not enough solid study has been done to determine
how well the surgery lowers breast cancer risk and deaths.
Jan Klijn, MD, of the Erasmus University Department of Clinical
Genetics in Rotterdam, The Netherlands, reported the findings last week at a
meeting of breast cancer specialists.
According to Klijn, of nearly 70 women who showed no signs of
cancer but had defects of either gene known to carry an increased risk of
breast cancer -- called BRCA 1 and BRCA 2 genes -- and underwent
preventative mastectomy of both breasts, none had developed breast tumors
approximately two years later.
The researchers also looked at a comparison group of 70 women
about the same age and with the same gene abnormalities but who did not have a
mastectomy. Although they were all healthy at the beginning of the study, the
comparison group had a higher than usual rate of breast cancer after two
Even though the study lasted only two years, statistics lead
the researchers to expect that by five years, none of the women who underwent
the mastectomies will have developed breast cancer, whereas almost 30% of those
who didn't have their breasts removed will develop the illness.
Normal BRCA 1 and BRCA 2 genes make proteins to
prevent abnormal cell growth that leads to cancer. But when a defect, or
mutation, is present in one of these genes, the possibility increases that a
woman will develop breast cancer. According to the American Center Society, a
woman who has inherited one of these genetic changes has a 50-60% increased
risk for the disease by the time she is 70 years old.
In the study, 42 of the mastectomy patients also had surgery to
remove their ovaries. In the comparison group -- all of whom had regular breast
exams rather than mastectomy -- 32 women had their ovaries removed, Klijn and
his colleagues report.
The Dutch researchers do not address the role that removal of
the ovaries may have played in outcomes of their study. However, other
researchers say removal of the ovaries can lower the risk of breast cancer
because they produce estrogen. Researchers have found that estrogen contributes
to development of breast tumors.