Follow-up MRI screening of BRCA1/2 mutation carriers.

11000 Background: Annual MRI screening is recommended as an adjunct to mammography for BRCA1 and BRCA2 mutation carriers (B1/2). Prophylactic oophorectomy (PO) has been shown to decrease breast cancer (BC) risk in B1/2; however, most studies of MRI surveillance of B1/2 either do not report or have low rates of PO.,91 B1/2 carriers underwent baseline mammogram within 3 months of first study MRI, and then underwent yearly mammograms and yearly MRI scans. Study endpoints were defined as date of BC diagnosis, date of prophylactic mastectomy, or date of most recent contact.,Of 91 patients, 79 (87%) had PO (72% prior to study entry, 15% in follow-up). Mean age was 47. 50 (55%) had B1 mutations; 41 (45%) had B2 mutations. 9 BC were detected in 91 women (9.9%) with a median follow-up of 3.18 years per person. 279 MRI scans were performed. 26 of 91 (29%) patients had at least one BIRADS 3 MRI. 15 of 91 (16%) patients had at least one BIRADS 4 or 5 MRI. A total of 18 MRI scans were scored as BIRADS 4 or 5 with 6 BC detected (33%). Of these 6 cancers, 2 were found on MRI only. Two additional cancers were diagnosed on study entry mammogram: both were seen on MRI (BIRADS 6). The final cancer was detected on breast self-exam 8 months after negative mammogram and MRI screening. At the time of clinical detection, the cancer was seen on both mammogram and MRI (BIRADS 4). All BC occurred in B1 carriers. 8/9 were invasive ductal carcinomas (one, DCIS); 7/9 were node negative. Both node positive BC occurred in women whose last MRI was 20 or more months prior to diagnosis. At year one, 18/91 (20%) MRI were BIRADS 3, while at year 3, 2/38 MRI were BIRADS 3 (5%) (p= 0.02).,In this population of B1/2 carriers, the majority of whom had PO, all BC occurred in B1 carriers. In addition, the two node positive BC were found in patients who had not had annual MRI screening, underscoring the importance of the current recommendation for annual MRI. BIRADS 3 category MRI (and need for short interval follow up scans) decrease with annual screening. No significant financial relationships to disclose.