Mammography results in male <i>BRCA</i> carriers.

10618 Background: Patients assigned male at birth (AMAB) with pathogenic germline variants (PGVs) in BRCA1 or BRCA2 ( BRCA+ ) have a 1-10% lifetime risk of developing breast cancer (BC). NCCN guidelines currently recommend that male BRCA1/2 carriers consider annual mammograms. However, there is minimal data on the mammography among male BRCA1/2 carriers. Methods: We identified a cohort of 489 BRCA + male patients with male gender identity from the electronic health record (EHR) at Penn Medicine who had no prior BC diagnosis. Charts were reviewed to determine indication for and results of mammography episodes between 2008-2024. A mammography episode was defined as all breast imaging studies obtained for a specific reason, i.e. asymptomatic screening or for symptoms within six months. An independent cohort of 1808 BRCA negative AMAB patients with male gender identity and no prior BC diagnosis from the Penn Medicine EHR was analyzed for the true positive rate of BI-RADS 4/5 findings. Results: Of 489 BRCA + individuals, 85 (17%) patients completed at least one mammography episode and 46 (9%) had at least one subsequent mammography episode during the study period. Of 85 BRCA + patients, 71% had BRCA2 PGVs. Of 404 patients who did not complete a mammogram, 270 were at least 50 years old at the time of data abstraction. Of these 270 patients, 50% had no discussion of mammograms in their charts, 8% of patients had a physician ordered mammogram that was not completed by the patient, and 42% had a shared decision-making discussion between the physician and patient indicating a decision against mammography. The first observed and subsequent mammography episodes were ordered for asymptomatic screening in 65% and 83% of 85 BRCA + individuals, respectively. In BRCA neg individuals, 92% of mammography episodes were for symptoms. Nine (11%) and one (2%) BRCA+ individuals were diagnosed with BC after the first observed or subsequent mammography episode, respectively. No breast cancers were identified on mammography episodes among asymptomatic patients. Combining all mammography data, the true positive rate of BI-RADS 4 mammograms was significantly higher in BRCA + vs BRCA neg individuals (71% vs 11%, p=0.0007); whereas the true positive rate of BI-RADS 5 mammograms was similar in BRCA + vs BRCA -neg individuals (100% vs 82%, p=0.54). Hormone receptor status and clinical stage of identified BC were similar between BRCA + and BRCA neg individuals. Conclusions: The majority of male BRCA1/2 carriers in our cohort did not complete mammography. All BC diagnosed in BRCA+ individuals were identified on mammography episodes obtained for symptoms. The true positive rate of a BI-RADS 4 mammogram was significantly higher in BRCA + compared to BRCA neg individuals. Additional data is needed regarding whether mammography identifies asymptomatic BC in male BRCA1/2 carriers and whether mammograms improve clinical outcomes.