BRCA variants not tied to worse cancer outcomes
NEW YORK (Reuters Health) - The outlook for breast cancer patients carrying variant versions of the BRCA genes is a subject of debate, but a new study suggests those women do just as well as patients with similar cancers, as long as they follow standard treatments.
The study, published in the Journal of Clinical Oncology, compared women with sporadic breast cancer to those who carry the so-called BRCA1 or BRCA2 mutations, which create variants of the genes that are linked to increased risk of developing breast or ovarian cancers.
"Basically what we're saying is with modern treatment a lot of these women are doing well," said Dr. Pamela Goodwin, lead author of the study, professor of medicine at the University of Toronto and scientist at Mount Sinai Hospital.
The study used information on over 3,000 women with breast cancer throughout the United States, Canada and Australia. The researchers examined about 90 women with BRCA1 mutations, 70 women with BRCA2 mutations and about 1,500 with sporadic breast cancers and a family history of the disease, and 1,500 women with sporadic cancers and no family history or known mutations.
The findings suggest that women with the BRCA1 mutation had about the same risk of their cancer returning compared to women with sporadic breast cancers. The women carrying the BRCA1 mutation also had a similar risk of dying.
Women with the BRCA2 mutation had a significantly higher risk that their cancer would come back or that they would die, compared to the women with sporadic breast cancer.
Goodwin notes the women carrying the BRCA2 mutation had worse tumors, and the association disappeared when the numbers were adjusted for factors such as age and tumor stage.
For those women with BRCA2 mutations, the ones who did not receive chemotherapy added on to their initial treatment saw their risk of dying increase over 300 percent.
"A lot of these women with genetic predisposition may develop tumors that have poor characteristics... But if they get the standard treatment available they seem to do OK," Goodwin told Reuters Health.
The findings suggest that the characteristics of each woman's tumor, not BRCA status, were most important to outcomes.
Whether women should be tested for BRCA mutations after receiving a breast cancer diagnosis remains unclear.
In an editorial accompanying the study, Dr. Steven Narod of the Women's College Research Institute in Toronto said it may be reasonable to test all patients with breast cancer when costs for genetic sequencing decline.
Myriad Genetics Inc, a company in Salt Lake City, patented the genes and conducts all of the tests in the U.S. to determine if a person carries them. The test can cost approximately $3,000.
However, Narod told Reuters Health that he believes in a targeted approach.
According to Goodwin, there are already a number of models to help clinicians determine who should be tested, but added that cost effectiveness will vary by health system.
