Biological therapy of salivary duct carcinoma

Background: The incidence of human epidermal growth factor receptor 2 positivity in salivary duct carcinoma ranges from 25 to 100 per cent and is associated with a poor outcome. Salivary duct carcinoma has significant pathological similarities to ductal carcinoma of the breast. Methods and results: A 49-year-old man developed lung and liver metastasis a few months after surgery and adjuvant radiotherapy for salivary duct carcinoma of the parotid gland. There was no response to palliative chemotherapy with doxorubicin. We followed the biological model of breast cancer, whereby two-thirds of human epidermal growth factor receptor 2 positive patients respond to a combination of docetaxel and human epidermal growth factor receptor 2 blocker (trastuzumab). A durable, complete response was achieved with this combination. A rationalised treatment approach targeting the biological characteristics of salivary duct carcinoma had proven successful.