SAN ANTONIO — The investigational OncoVue breast cancer risk test provided a 2.4-fold improvement over the Gail model in accurately identifying women at elevated risk of breast cancer in a blinded validation study.
This is the third independent study demonstrating that the OncoVue individualized breast cancer risk estimator provides more accurate estimates than does the widely used Gail model, Dr. Kathie M. Dalessandri said at the San Antonio Breast Cancer Symposium.
OncoVue integrates genetic testing for 22 single nucleotide polymorphism variants located on 19 genes with classic Gail model personal risk factors, such as age at first menses and first live birth and the number of first-degree relatives having breast cancer. The genetic test uses DNA from a saliva sample, explained Dr. Dalessandri of the University of California, San Francisco, and the Buck Institute for Age Research in Novato, Calif.
She reported on 169 women diagnosed with breast cancer during 1997–1999, when they were a mean of 54 years old, and 177 age-matched controls. All were enrolled in the Marin County Study of Breast Cancer Adolescent Risk Factors, which was undertaken in order to determine the source of the unusually high incidence of breast cancer in county residents dating back to the early 1990s.
OncoVue proved to be 2.4-fold more accurate than the Gail model at identifying women with a 12% or greater risk of developing breast cancer between ages 30 and 69, which is 1.5 times the national average risk. The Gail model identified as high risk 37 of the 177 women who went on to develop breast cancer. OncoVue identified 56 of the women, representing a 51% improvement.
The Food and Drug Administration is developing standards for gene test-based products that are aimed at assessing breast cancer risk in the general population. It has yet to approve any such tests aside from those for BRCA1 and BRCA2, which account for only a small percentage of breast cancers. The OncoVue test, developed by InterGenetics Inc. of Oklahoma City, is available at roughly three dozen breast care centers around the country under existing FDA rules governing laboratory testing.
“Women are clamoring for genetic tests like this one,” Dr. Dalessandri said.
She sees OncoVue as playing two major roles in the future: in the clinic (to help women obtain a more accurate individualized risk assessment than conventional risk factors can provide), and in large-scale breast cancer prevention trials. “You want to accurately assess risk before putting patients in a trial,” she noted.
Most of the 22 single nucleotide polymorphism variants assessed in OncoVue relate to steroid hormone metabolism, DNA repair, apoptosis, growth factors, and detoxification, according to Dr. Dalessandri.
The study was supported by the California Breast Cancer Research Program and InterGenetics. Dr. Dalessandri reported having no financial conflicts of interest.
'Women are clamoring for genetic tests like this one.' DR. DALESSANDRI