MONDAY, April 5, 2004 (HealthDayNews) -- Women recently diagnosed with breast cancer who test positive for BRCA1 or BRCA 2 gene mutations are twice as likely to choose having a double mastectomy to reduce their risk for future breast cancer in the opposite breast.
An estimated 5 percent to 10 percent of all newly diagnosed breast cancer patients carry one of these mutations. These women have a greater risk (up to 60 percent greater, in some cases) of developing cancer in the opposite breast for at least a decade following the original diagnosis.
The current study, which appears April 5 in the online issue of the Journal of Clinical Oncology, is the largest to look at the effect of genetic testing on treatment and surgical decisions involving breast cancer.
"This is a very strong study that shows the value of knowing genetic information in high-risk women for breast cancer," said Dr. Jay Brooks, chief of hematology/oncology at the Ochsner Clinic Foundation in Baton Rouge, La. "I think we're moving beyond all the fears of genetic testing and understanding the important value."
"This study shows that offering genetic counseling and then testing in the post-diagnosis period [to high-risk women] is feasible. It can be done," added Marc Schwartz, lead author of the study, and an associate professor of oncology at Georgetown University. "Physicians may want to discuss the option of genetic testing."
An earlier study, published in March, found that women with the BRCA 1 or 2 mutation who underwent a preventive double mastectomy reduced the risk of developing the disease by 90 percent. These women had not yet developed breast cancer.
Right now, however, genetic testing is limited by a number of factors, said Dr. Mary B. Daly, author of an accompanying editorial in the same issue of the journal.
"One is the sort of triage process, who one should even consider ordering test on," she pointed out. "Secondly, the cost of the test is quite significant -- in the range of $2,000 to $3,000 -- and insurance companies vary in how much, if any, of that they will cover."
Daly, director of cancer prevention and control at the Fox Chase Cancer Center in Philadelphia, said she can wait up to six weeks and more for an insurance company to decide on whether it will pay for a test. Counseling is rarely if ever covered.
For the current study, the researchers provided free genetic counseling and free rapid testing (available in about two weeks) for the BRCA 1 and 2 mutations to 194 women who had just been diagnosed with breast cancer but who had not yet undergone surgery.
Thirty-one women tested positive for one of the mutations. Of these, 48 percent chose to undergo a double mastectomy, while 24 percent of the remaining women (who either had no mutations or a mutation of unknown significance) opted for the double procedure.
The fact that almost half of the women with a positive test result elected to have a bilateral mastectomy was not surprising, said Schwartz. More surprising, at least initially, was that almost a quarter of women who had tested negative for the mutations also chose to have this procedure. In retrospect, this finding also made sense.
"The women in this sample who got uninformative test results and went on and got bilateral surgery tended to be at higher risk," Schwartz explained. "Some of the women had a lobular cancer, and that places them at higher risk. Some had had multiple biopsies in the contralateral breast, so they were at higher risk. In some, the initial breast cancer was missed by routine mammography, so they might have decided that this was the safer thing to do. There were mitigating factors in each of the cases."
The study also found that physician recommendations also played a strong role in decision-making. Women who said their physician had recommended testing were about three times more likely to get tested. Those who said their doctor had recommended a bilateral mastectomy were five times more likely to choose that course of action.
Although the scenario presented in this study (free testing and counseling) is not true-to-life, the results may help the drive toward making genetic testing and counseling more available.
"We know that the only real preventive option that has a huge guarantee is a prophylactic mastectomy," Daly said. "Until we have another equally effective means of prevention, it's a reasonable option for those women to consider. The nice thing about considering [prophylactic surgery] at the time of breast cancer surgery is that you can make the surgical effects less of an issue."
More information
For more on genetic testing for BRCA 1 and BRCA 2, visit the National Cancer Institute or the U.S. Centers for Disease Control and Prevention.
