Mammographic and contrast-enhanced spectral mammography imaging findings of HER2-positive cancers according to hormone receptor status

Background Breast cancer is the leading cause of cancer-related mortality in women. Human epidermal growth factor receptor 2 (HER2) overexpression is seen in 20 out of 100 invasive breast cancers. Among HER2+ patients, two distinct hormone receptor (HR) subtypes can be defined: HR-positive (HR+) and HR-negative (HR−) each of which with unique therapeutic response and survival pattern. Contrast-enhanced spectral mammography (CESM) is an emerging novel imaging modality that offers diagnostic performance comparable to contrast-enhanced MRI. The purpose of this retrospective study was to describe the CESM features of HER2+ breast cancers according to hormone receptor status and to assess whether specific mammographic and CESM imaging features can differentiate between HER2+/HR+ and HER2+/HR− breast cancers potentially aiding treatment planning in HER2+ breast cancer patients. Results A total of 61 patients were included. Twenty-nine cases (47.5%) were HER2+/HR+ and 32 cases (52.5%) were HER2+/HR−. No statistically significant difference was found between mammographic imaging presentations and hormonal status. HR- were more likely to be multifocal ( P 0.018), rounded or oval (P 0.008), circumscribed ( P 0.004), and with associated non-mass enhancement (NME) ( P < 0.001). HR+ cancers showed a tendency for irregular shape ( P 0.008), spiculated outline ( P 0.004), and heterogeneous ( P 0.021) or ring ( P 0.046) enhancement. Conclusions HER2+ tumors have different demographic, pathologic and imaging features according to the hormone receptor status. Because the two subtypes of HER2 breast cancer have different clinical outcomes, CESM imaging features can potentially enhance patient outcome by accelerating the diagnosis and treatment.