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Introduction

Salivary duct carcinoma (SDC) is a rare tumor of the salivary glands, representing 1%–3% of all malignant salivary tumors . SDC progresses rapidly and is frequently diagnosed at an advanced stage, with a 5-year survival rate of 11.5%–26.9% . While surgical resection with postoperative radiotherapy is the standard treatment, there is a high risk of both local (48%) and distant (48%) recurrence . In view of the poor survival rate, a structured therapeutic approach should be developed to improve disease outcome.

SDC is pathologically similar to ductal carcinoma of the breast . Recent studies showed human epidermal growth factor receptor 2 (HER2) overexpression in SDC and its association with poor prognosis , similar to HER2-positive ductal carcinoma of the breast. Trastuzumab, a monoclonal antibody that interferes with the HER2 receptor, is one treatment option for HER2-positive SDC ; however, its efficacy remains uncertain. On the other hand, androgen receptor (AR) overexpression is more common in SDC (43%–92.3%) , and androgen deprivation therapy (ADT) is beneficial in patients with recurrent or disseminated disease .

The objectives of this study were to determine the proportion of HER2- or AR-positive SDC patients and to evaluate the association between HER2 and AR positivity with prognosis. Moreover, we report findings for one patient with AR-positive SDC who was prescribed ADT.