Genetic counseling for BRCA1/2 among a population-based cohort of women with breast carcinoma in situ
Objective: To assess the effects of genetic counseling for BRCA1/2 among a population-based cohort of women with breast carcinoma in situ (BCIS).
Methods: The data are 341 BCIS cases diagnosed among female residents aged 20 to 79 years from the state of Connecticut between 9/15/94 and 3/14/98. The women were participants in a large population-based case-control study of BCIS. Cases were asked to donate a blood/buccal specimen for testing of mutations in BRCA1/2. Cases completed risk assessment questionnaires during pre- and post-testing genetic counseling sessions. Changes in risk assessment after counseling are examined overall and by BRCAPRO probability, BRCA1/2 mutation status, family history, age, and race.
Results: On average, cases reported a 40% probability of carrying a mutation in BRCA1/2, significantly greater than would be predicted on the basis of BRCAPRO scores (p < 0.01). Counseling was associated with an overall reduction in perception of risk for carrying a mutation in the BRCA1 or BRCA2 genes (p < 0.01), including among individuals with a family history of breast and ovarian cancer. Perceptions of personal ovarian cancer risk did not change after counseling.
Conclusion: Genetic counseling is associated with an improved understanding of the risks associated with BRCA1 and BRCA2 within a population-based cohort of women with BCIS.