Breast cancer risk assessment in patients who test negative for a hereditary cancer syndrome.

Background: The majority of women who undergo genetic testing due to a significant family history of breast cancer will receive a negative result. The purpose of this study was to calculate the lifetime risk of breast cancer in women undergoing genetic counseling who received an uninformative genetic test result.

Methods: A retrospective chart review of mutation-negative women presenting to a cancer risk assessment clinic was performed. Lifetime risks of breast cancer were calculated using the Claus, Gail, and Tyrer-Cuzick risk assessment models.

Results: Approximately half (51%) of the women were classified as high-risk by at least one risk assessment model. The Tyrer-Cuzick model identified the highest proportion (43.2%) of patients as high-risk. Four percent (n = 4) of the sample was considered high-risk by all three models.

Conclusions: More than half (51%) of women who underwent genetic counseling and received an uninformative negative genetic test result had a significantly elevated risk for the development of breast cancer. It is, therefore, imperative that women do not conclude that a negative genetic test result represents a lack of risk.