Breast Cancer & Genes: Assessing Risk
Study Questions Accuracy of Genetic Risk Models Used to Determine Testing
Mutation Uncommon continued...
When these women were questioned further about their family history, half of them (153) were determined by researchers to have too few close female relatives to accurately assess risk, defined as fewer than two females relatives age 45 or older on both their mother's and father's sides of the family.
Genetic testing revealed that these women had a 14% risk of having a mutation, compared with a 5% risk among women with a larger number of female relatives who survived to their mid-40s without developing breast cancer.
"The likelihood of finding a mutation was almost three times greater [among the women with fewer older female relatives]," Weitzel says. "We are clearly missing women who could benefit from knowing their genetic risk."
Understanding the Limitations
Cancer geneticist and gynecologist Noah D. Kauff, MD, of Memorial-Sloan Kettering Cancer Center, agrees.
"We have to understand the models and their limitations if we are going to use them," he says. "They likely still have a role in helping us identify patients who would benefit from genetic testing, but it is important that they are not used in isolation."
Breast cancer patients with BRCA mutations are generally treated more aggressively; they are at increased risk for another breast cancer and ovarian cancer.
The American Cancer Society now recommends annual breast screening with magnetic resonance imaging (MRI) along with mammography for high-risk women, as determined by existing family-risk models.
Kauff tells WebMD that the recommendation illustrates the importance of finding better ways to identify women at increased risk.
"If these models are incomplete for testing, they are obviously incomplete for making decisions about who should be screened and treated," he says.