Clinicopathological and ultrasound characteristics of breast cancer in BRCA1 and BRCA2 mutation carriers

Purpose BRCA1 and BRCA2 tumors exhibit different characteristics. This study aimed to assess and compare the ultrasound findings and pathologic features of BRCA1 and BRCA2 breast cancers. To our knowledge, this is the first study to examine the mass formation, vascularity, and elasticity in breast cancers of BRCA -positive Japanese women. Methods We identified patients with breast cancer harboring BRCA1 or BRCA2 mutations. After excluding patients who underwent chemotherapy or surgery before the ultrasound, we evaluated 89 cancers in BRCA1 -positive and 83 in BRCA2 -positive patients. The ultrasound images were reviewed by three radiologists in consensus. Imaging features, including vascularity and elasticity, were assessed. Pathological data, including tumor subtypes, were reviewed. Results Significant differences in tumor morphology, peripheral features, posterior echoes, echogenic foci, and vascularity were observed between BRCA1 and BRCA2 tumors. BRCA1 breast cancers tended to be posteriorly accentuating and hypervascular. In contrast, BRCA2 tumors were less likely to form masses. In cases where a tumor formed a mass, it tended to show posterior attenuation, indistinct margins, and echogenic foci. In pathological comparisons, BRCA1 cancers tended to be triple-negative subtypes. In contrast, BRCA2 cancers tended to be luminal or luminal-human epidermal growth factor receptor 2 subtypes. Conclusion In the surveillance of BRCA mutation carriers, radiologists should be aware that the morphological differences between tumors are quite different between BRCA1 and BRCA2 patients.