Salivary duct carcinoma: Prospective multicenter study of 61 cases of the Reseau d'Expertise Francais des Cancers ORL Rares

Background The purposes of this study were to describe the characteristics of a prospective multicenter series of patients with salivary duct carcinoma and to investigate prognostic factors. Methods Patients included for salivary duct carcinoma between 2009 and 2016 in the Reseau d'Expertise Francais des Cancers ORL Rares (REFCOR) database were selected. Immunohistochemical analyses were performed. Results Sixty-one patients were included in this study. The primary site was the parotid gland in 90% of the cases. Fifty-seven percent of the tumors were stage IV, 65% of patients had lymph node involvement, and 10% had metastases. Tumors showed androgen receptor (89%) and human epidermal growth factor receptor 2 (HER2)/neu (36%). Ninety-four percent of patients underwent surgery and 86% had postoperative radiotherapy. Six patients were treated with targeted therapies. The 3-year overall survival (OS) was 74% and the 3-year disease-free survival (DFS) was 44%. Tumor stages III to IV reduced DFS (hazard ratio [HR] 4.3; P = .04). The N2/3 class reduced distant metastasis-free survival (HR 7.3; P = .007). Conclusion Salivary duct carcinoma prognosis is poor and is correlated with tumor stage and lymph node classification. Androgen receptor and HER2/neu should be tested as they offer the possibility of targeted therapies.