Androgen Deprivation Therapy for Patients with Androgen-Receptor-Positive Metastatic Salivary Duct Carcinoma: A Case Report and Review of the Literature.

Salivary duct carcinoma (SDC) is a rare and aggressive malignancy with high rates of recurrence and metastasis. There are no standard treatment options available for patients with recurrence and metastases. The case of a 61-year-old male with SDC of the left parotid gland is presented in this study. The results revealed that the patient's tumour had strong positive staining for androgen receptor (AR) expression, mutations in HRAS and PIK3CA but not in other related genes, and no gene amplification of HER-2. After the primary therapy of parotidectomy with neck dissection and postoperative radiation, bone metastases were found in the ribs, pelvis and spine. Androgen deprivation therapy (ADT) involving combined androgen blockade (CAB) was effective as the first-line therapy for the patient's metastases and resulted in a progression-free survival (PFS) of over 7 months to date. In conclusion, androgen deprivation therapy is recommended for patients with recurrent or metastatic SDC positive for androgen receptor expression.