Survival rates and prognostic factors for infiltrating salivary duct carcinoma: Analysis of 228 cases from the Surveillance, Epidemiology, and End Results database

Background The survival rates and prognostic factors for salivary duct carcinoma (SDC) are not clear. Methods Survival estimates and prognostic factors were evaluated for 228 patients with SDC identified from the Surveillance, Epidemiology, and End Results (SEER) database. Results Median overall survival (OS) duration for patients with SDC was 79 months and 5-year disease-specific survival (DSS) rate was 64%. Among patients with SDC with lymph node involvement, larger primary tumor size (>3 cm) was associated with twice the risk of death (p <.03). Factors predictive of improved DSS were age (p =.01), tumor size (p =.006), tumor grade (p =.02), and lymph node involvement (p <.001). Adjuvant radiotherapy did not improve survival when compared to surgery alone for early-stage (I-II) disease (p =.28). Conclusion Younger patients with SDC (<50 years) showed a better prognosis. Primary tumor size and lymph node involvement were independent and additive risk factors for poor prognosis. The role of adjuvant radiotherapy in the treatment of SDC needs to be explored further.