Validation of a tool for identifying women at high risk for hereditary breast cancer

Sep 11 2006

A new screening tool for the general practitioner effectively identifies patients at risk for hereditary breast cancer, according to a new study.

Published in the October 15, 2006 issue of CANCER, a peer-reviewed journal of the American Cancer Society, the study reveals a newly developed, simple scoring tool called the "pedigree assessment tool" (PAT) was 100 percent sensitive in identifying women at high risk for the hereditary breast cancer syndrome. The PAT outperformed another commonly used tool, the modified Gail model, in correctly assessing individual patient risk.

Only two to three percent of breast cancers are known to be the result of hereditary syndromes - that is, caused by germline mutations. The most commonly recognized breast cancer genes are BRCA1 and BRCA2. While rare, inheritance of these mutated genes leads to an approximately 80 percent lifetime risk of developing breast cancer. Current management protocols offer hope to these mutation carriers that breast cancer can be either prevented or managed effectively through intensive early detection programs. Therefore, identification of the high risk patients with this hereditary cancer syndrome in the general practice is critical for early referral for genetic counseling and rigorous screening.

Several quantitative assessments are available to physicians to calculate an individual patient's risk for developing breast cancer. One example is the modified Gail model. Collecting familial and individual risk data, the tool is able to quantifiably assess both five-year and lifetime absolute risk of developing invasive breast cancer. One of its weaknesses, according to some, is that it may substantially underestimate breast cancer risk in the subgroup of women with hereditary breast cancer syndromes and is not well-suited for identifying these women.

Led by Kent F. Hoskins, M.D. of the OSF Saint Anthony Center for Cancer Care in Rockford, IL, researchers developed the PAT as a simple, scoring tool to better "identify women in a primary care setting with family cancer histories suggesting a hereditary breast cancer syndrome." In this study, they tested the PAT against the Gail model in a population of 3906 women to identify potential BRCA mutation carriers and risk-stratify them.

PAT scoring was effective at identifying the 86 high risk patients with potential BRCA hereditary syndromes. With a PAT score of 8 or greater (i.e., high BRCA probability), sensitivity and specificity were 100 percent and 93 percent, respectively. In contrast, the Gail model calculations were no better than 73 percent in regards to specificity, and that at the expense of sensitivity, which fell to 27 percent. Further comparison between the PAT and the Gail tools showed that the PAT was more effective at assigning women to the high risk BRCA group.

The authors conclude that this study "demonstrated that a simple point scoring system (PAT) performs very well in identifying women in a screening mammography population who would benefit from referral to a cancer risk clinic for genetic counseling and consideration of DNA testing of appropriate family members."

In the context of developing comprehensive breast screening tools for the general practice, the authors assert that "such a strategy could be effectively employed by combining the Gail model with a tool like the PAT."