Ductal carcinoma in situ (DCIS) is a well-recognized precursor to invasive breast cancer that is associated with a 14%-to-60% risk for progression to invasive disease at 10 years after diagnosis. The incidence of DCIS in women with BRCA mutations, however, is still uncertain, and a diagnosis of DCIS has not been included in predictive models that determine whether a woman should undergo genetic testing. In this retrospective study, investigators assessed the risk for DCIS, invasive breast cancer, or both in women with a family history of breast cancer who underwent genetic testing for BRCA mutations from 1996 through 2003.
Of the 398 women studied, 129 tested positive for BRCA mutations, and 269 were noncarriers. The proportion of women diag…