Contralateral breast cancer risk reduction choices in BRCA negative women with breast cancer under age 50.

Abstract

Abstract Abstract #1094 Rationale: Genetic testing for mutations in the BRCA1 and BRCA2 genes has enabled clinicians to provide contralateral breast cancer (CBC) risk estimates for women with breast cancer. Carriers of BRCA1 or BRCA2 deleterious mutations (BRCA+) have an increased risk of developing CBC compared to women without deleterious mutations (BRCA-). Guidelines for screening, including MRI and mammogram, and risk management options, such as contralateral prophylactic mastectomies (CPM), have been developed for BRCA+ women. However, many who undergo genetic testing are BRCA-. This result is often termed “uninformative negative” and can be interpreted as reassuring if the woman has little or no family history of breast and ovarian cancer or as not reassuring if the woman has a strong family history of breast and ovarian cancer. The uninformative nature of a BRCA- result makes clinicians' assessment of CBC risk for BRCA- women difficult, with less defined screening guidelines. We evaluated current CBC risk reduction strategies used by women under the age of 50 with reassuring or non-reassuring BRCA- test results.
 Methods: 634 breast cancer patients diagnosed under 50 were seen for genetic testing at MDACC between 1997-2008. 368 tested negative for BRCA mutations. Medical records were reviewed to determine age of cancer diagnosis, interpretation of the BRCA- result (i.e., reassuring vs. non-reassuring), and risk reduction choices made including CPM and prophylactic total abdominal hysterectomy-bilateral salpingo-oopherectomy (TAH/BSO). Interpretation of the BRCA- result was determined by a genetic counselor and was based on family history information provided by the patient. Fisher's exact test was used to detect differences between groups.
 Results: 34% of the women engaged in at least one preventative measure. Risk reduction choices made depended on the interpretation of the test result and the age of breast cancer diagnosis. In women diagnosed after 40, CBC risk reduction behaviors were similar regardless of having a reassuring or non-reassuring BRCA- result. In women diagnosed under 40, there was a higher uptake of prophylactic surgeries in women with non-reassuring negative results compared to reassuring negative results (CPM: 39.5% vs. 20.4%, p < 0.05; TAH/BSO: 18.4% vs. 2%, p < 0.01). Among women with reassuring negative results, CPM uptake after genetic counseling was higher in younger women compared to older women (11.2% vs. 5.6%, p < 0.05). CBC risk reduction choices were similar between younger and older women with non-reassuring negative results.
 Discussion: Although definitive screening guidelines are not provided for BRCA- women, many women with a negative result engage in risk reduction procedures. The interpretation of the negative test result and the age of breast cancer diagnosis appear to play a role in this decision making process. Because interpretation of a negative test result is used in CBC risk management decisions, this study highlights the importance of post-genetic testing counseling by professionals who can provide an accurate interpretation of genetic testing results. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1094.