Abstract P2-10-03: Impact of BRCA 1 and 2 Gene Mutation Testing on Surgical Decision-Making in Newly Diagnosed Breast Cancer Patients
Authors: D'Souza A , Dohany L , Ducaine W , Zakalik D. 
Published: April 2011

BACKGROUND: Breast cancer patients with BRCA 1 or 2 gene mutations demonstrate a high lifetime incidence of a second breast cancer in the contralateral breast. These patients may benefit from a bilateral mastectomy (BLM) with an intent of risk reduction. If provided in the right window between cancer diagnosis and definitive treatment, genetic cancer risk assessment would aid high-risk patients in making an informed decision with respect to planning appropriate surgery.

OBJECTIVE: The purpose of this study is to assess the feasibility of BRCA 1 and BRCA 2 gene mutation testing in the pre-operative setting and to determine whether test results altered final surgical decision. METHODS: Newly diagnosed breast cancer patients referred to the cancer genetics clinic between April 2009 to March 2010 were identified. All patients were sent for genetic cancer risk assessment due to the presence of clinical features suggestive of hereditary breast cancer based on current guidelines. A retrospective chart review of the patients was performed. RESULTS: 81 patients were identified. 6 patients were excluded as they went on to have surgery in a different hospital and were lost to follow up. 3 patients did not meet criteria for genetic testing. 1 patient was excluded as she was scheduled for a BLM prior to being seen in our clinic, and 1 patient was receiving neoadjuvant chemotherapy and hadn't had surgery at the time of data collection. Of the remaining 70 patients, the mean age was 48 years (29-74 years) with 81% being of caucasian race and 11% having Ashkenazi-Jewish ethnicity. 30% had two or more first degree and 68% had two or more second degree relatives with cancer. 29% had a first degree relative who had died of cancer. 74% had a diagnosis of invasive breast cancer, where as 26% only had in-situ disease. Further, 21% had grade 1, 37% with grade 2 and rest with grade 3 tumors. 81% tested negative for BRCA gene mutations, 9% were positive for either BRCA 1/2, 6% had variants of uncertain significance(VUS) and 4% didn't undergo genetic testing for various reasons. It took an average of 9.3 days (4-31 days) to obtain results. 54% of women aged 40 years or younger chose BLM versus 25% of women over 40 (p=0.015). 6.7% of women with low grade breast cancer underwent BLM versus 54% with moderate grade and 34% with high grade cancer (p=0.0098). Based on the BRCA results, 83% of BRCA positive women chose BLM versus 33% of BRCA negative (true negative and VUS) patients (p=0.024). A negative result had a greater influence in favor of a unilateral surgery in 67% of BRCA negative patients. In contrast, majority of women who underwent BLM were not influenced solely by their gene test results.

CONCLUSIONS: Amongst newly diagnosed breast cancer patients, genetic testing for hereditary breast and/or ovarian cancer syndromes can influence surgical decision in a risk-appropriate way. Our results show that genetic cancer risk assessment can be effectively incorporated in newly diagnosed breast cancer patients and can help guide the decision about the optimal surgery without a significant delay. A negative BRCA gene result seemed to help patients reach a decision favoring unilateral surgery.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-10-03.