Salivary duct carcinoma: evaluation of treatment and outcome in a tertiary referral institute.

PURPOSE: The aggressive behavior of salivary duct carcinoma (SDC) necessitates an aggressive treatment strategy, including surgery and radiotherapy (RT). We evaluated practice patterns and treatment outcomes in patients with SDC treated in our Institute. METHODS: Patients with SDC of the parotid or submandibular gland treated with curative intention in our Institute from 1998 until 2016 were reviewed. Our diagnostic workup and treatment strategy were evaluated together with treatment outcomes. RESULTS: Fifteen patients with SDC were included. Staging included MRI and ultrasound-guided fine needle aspiration cytology. Only in a minority (20%) of patients, the preoperative diagnosis of SDC was raised due to positive immunohistochemical staining for the androgen receptor (AR) on cytology. All patients were treated with (sub)total resection of the salivary gland and 53% underwent a therapeutic neck dissection. All patients except one received postoperative RT. Immunohistochemical staining was found positive for AR (100%) and human epidermal growth factor receptor 2 (HER2/neu) (13%). No local recurrences occurred. Regional and distant failure rates were 20% and 40%, respectively. CONCLUSIONS: Excellent local control rates can be achieved with extensive (local) surgical treatment and postoperative RT. In case of lymph node metastases, a neck dissection with adjuvant postoperative RT is warranted. In patients with node-negative disease, a less aggressive approach for the neck seems feasible to reduce treatment-related morbidity.