BRCA mutation testing warranted in women with bilateral breast cancer, regardless of family history: 25% have deleterious mutation.(News)

SAN ANTONIO -- Women with bilateral invasive breast cancer have a high prevalence of BRCA1 and BRCA2 mutations regardless of whether they possess a strong family history of breast or ovarian cancer, Alicia A. Parlanti reported at a breast cancer symposium sponsored by the Cancer Therapy and Research Center.

Based upon this observation in a large new study, all women with bilateral invasive breast cancer--including those in whom the first and second diagnoses are separated by decades--ought to be offered genetic risk assessment services including BRCA mutation testing, said Ms. Parlanti of Myriad Genetic Laboratories in Salt Lake City.

She reported on 11,603 women with invasive breast cancer who underwent BRCA mutation testing at Myriad upon their physicians' orders. Among the subset of 1,565 women with a reported diagnosis of bilateral breast cancer, the prevalence of deleterious mutations was 25.4%. That rate is up to fivefold higher than in some prior reports in the literature; however, those earlier reports are unpersuasive because of very small sample sizes, she continued.

In her study, more than 10,000 women underwent analysis of the full BRCA sequence. The remaining 1,075 had a genetic analysis restricted to the three specific Ashkenazi Jewish founder mutations.