Treatment of Male Breast Cancer by Dual Human Epidermal Growth Factor Receptor 2 (HER2) Blockade and Response Prediction Using Novel Optical Tomography Imaging: A Case Report.

Male breast cancer, although rare, is on the rise. Prospective clinical trials are unlikely and current management mirrors that of post-menopausal women. Neoadjuvant chemotherapy is widely used and pathologic complete response (pCR) predicts long-term survival. The addition of dual HER2 (human epidermal growth factor receptor 2) blockade has shown the highest pCR rates; however, there is no published data of this approach in men. Also, newer monitoring tools are necessary during a neoadjuvant therapy to help personalize treatment.  Here, we describe the case of a 64-year-old man with Stage IIB (tumor size 2 to 5 cm with involvement of axillary lymph nodes), high-grade estrogen receptor, progesterone receptor, and HER2-positive invasive ductal carcinoma with a germline breast cancer susceptibility gene 1 (BRCA1) mutation who was treated in a neoadjuvant fashion with dual HER2 blockade and platinum-based chemotherapy regimen. A novel predictive tool, ultrasound-localized diffuse optical tomography, was used to monitor his progress during treatment.