Clinical value of adjuvant therapy on the prognosis of ductal carcinoma of the major salivary gland: a large-scale cohort study.

Abstract

To explore the clinical characteristics, prognostic factors, and value of adjuvant therapy for major salivary duct carcinoma (SDC). Data of SDC patients who received surgery was obtained from Surveillance, Epidemiology, and End Results (SEER) database (2004-2016). Kaplan-Meier and Cox regression analyses were performed to assess prognostic factors. Propensity score matching (PSM) was done to evaluate the clinical value of adjuvant therapy. A total of 287 patients were enrolled. The 5-year overall survival (OS) and disease-specific survival (DSS) rates were 53.8% and 70.8%, respectively. In the univariate analysis, tumor size, T, N, TNM staging, SEER combined staging, number of regional lymph nodes examined, and number of positive lymph nodes were associated with OS and DSS. Age and primary surgical methods were also related to OS. Among patients with negative lymph nodes, patients with tumor size > 4cm had significantly worse prognosis (P = 0.009). Multivariate analysis showed that age > 75years, T3-4, and positive lymph nodes were independent risk factors for SDC. After PSM, the prognostic factors were age, tumor site, and T and N stage. Postoperative radiotherapy could improve OS in patients with tumor size > 4cm (P = 0.049). Advanced age, submandibular gland lesions, T3-4stage, and lymph node involvement were independent prognostic factors for SDC. In patients with tumors > 4cm, adjuvant radiotherapy improved the OS of SDC patients.