Abstract P2-09-15: Rapid BRCA analysis: Experience of a single institution

Abstract

Abstract The interest of rapid BRCA analysis, even before the initial treatment could modify the surgical indications (ie total mastectomy and immediate reconstruction even in case where tumorectomy would be suitable). The aim of this study was to evaluate the indications and consequences of this rapid determination of BRCA status in our institution. Patients Rapid BRCA analysis was conducted in 129 patients (pts) treated for breast cancer and addressed to the genetician at Oscar Lambret Center between 2009 and 2014: in 98 pts to discuss breast and axilla surgical modalities, in 4 cases to discuss oophorectomy, in 3 cases to have access to PARP inhibitors. In the other 24 pts, the reasons were debatable: patient leaving abroad, patient requiring reproductive assisted technology..... Results 38 deleterious mutations (29,4%) were identified (31 BRCA1, 7 BRCA2) in 38 pts. Cancer treatment was on going for 107 pts, programmed for 12 pts and finished for 10. The median time between cancer diagnosis and genetic counseling was 81 days (5-5160), between blood sample collection and BRCAs analysis 37 days (13-132), between availability of the laboratory results and the information to the patient: 39 days (1-234); 7 pts (5.4%) never came to obtain the laboratory results. Treatment was modified after genetic counselling for 8 pts out of 119 (7%). Six of them had BRCA1 deleterious mutations. Three decided subsequent radical mastectomy and adjuvant radiation was cancelled, another had a radical mastectomy before radiation, another treated for bilateral breast cancer had a bilateral radical mastectomy before radiation and the last treated for unilateral breast cancer had a bilateral radical mastectomy before radiation. Out of these 8 pts, two did not have a deleterious mutation. One had a bilateral radical mastectomy before laboratory result and one with BRCA variant of unknown significance had a homolateral radical mastectomy. Conclusion discussion Our experience shows that rapid BRCA analysis is feasible. In this selected population the mutation rate is very high. However, first, it appears that indications for rapid BRCA analysis were variable and not always relevant. Second, genetic result impacts on treatment only in 7% of pts. Indications could be justified by the use of PARP inhibitors. Up to now, the indications of rapid genetic analysis are rare. Citation Format: Mailliez A, Herin H, Revillion F, Adenis C, Peyrat J-P, Bonneterre J. Rapid BRCA analysis: Experience of a single institution. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-09-15.