Genetic Cancer Screening Works

Medically Reviewed by Charlotte E. Grayson Mathis, MD
From the WebMD Archives

March 1, 2002 -- Since a screening blood test for two breast and ovarian cancer genes (BRCA1 and BRCA2) was first introduced, there has been debate over whether learning about one's risk really offers women any benefit. Now, a new study provides the first real evidence that screening at-risk women for the genes associated with breast and ovarian can help save lives.

People who have the BRCA mutations have a significantly increased risk for early-onset breast cancer and also a higher lifetime risk of ovarian cancer. In addition, the mutation carries an increased risk for additional recurrences of cancerous tumors in breast cancer survivors and a higher risk of developing breast cancer for males.

The study, published in the March 1 issue of the Journal of Clinical Oncology, found that breast and ovarian cancers can be caught at an early stage in women who have the highest hereditary risk.

"These results provide the first prospective evidence that BRCA testing can lead to interventions that can result in the diagnosis of early stage breast and ovarian cancers," says study author Kenneth Offit, MD, PhD, chief of clinical genetics service at Memorial Sloan-Kettering Cancer Center in New York, in a news release.

Researchers looked at 250 women identified as having mutations in the BRCA1 or BRCA2 genes, predisposing them to cancer. Each received recommendations for intensified screening and/or preventive surgery as part of their genetic counseling. During the course of the five-year study, 21 of the women were diagnosed with early breast or ovarian cancers that were detected thanks to these heightened efforts.

Breast cancer was found in 12 women who chose increased surveillance. Half were found by mammograms and half were found in physical examinations during the interval between annual mammograms.

Twenty-nine women opted to undergo preventive removal of breast tissue in order to reduce their risk of developing breast cancer. Early-stage breast cancer tumors were found in two of these women at the time of surgery.

Among the 89 women with intact ovaries who chose intensified screening efforts, twice yearly vaginal ultrasounds and blood tests detected five ovarian cancers. All were found at an earlier-than-normal stage for this disease, which is often not detected until it has spread to other areas. Of the 90 women who chose preventive removal of their ovaries, two early stage ovarian cancers were discovered.

"Further studies will be needed to measure outcomes after surgery and early detection," says study co-author Lauren Scheuer, MS, in a news release. "However, our preliminary results are encouraging. They underscore the importance of genetic counseling and education for women with proven risk factors for breast and ovarian cancers."

Researchers estimate that about 950,000 American women carry the BRCA1 and BRCA2 mutations.