UC San Diego

BACKGROUND: Salivary duct carcinoma (SDC) is a rare and aggressive malignancy with limited population-based data. METHODS: Incidence trends and survival outcomes were analyzed using the Surveillance, Epidemiology, and End Results database. RESULTS: A total of 955 cases were identified. The age-adjusted incidence rate increased from 0.158 in 2000 to 1.18 in 2022 (average annual percent change, 10.38%; p < 0.001), accelerating after 2012. Increases were more pronounced among females, older patients, regional-stage disease, and tumors > 2 cm. The 5-year disease-specific survival (DSS) and overall survival were 60.6% and 51.2%, respectively. Advanced age, non-parotid site, larger tumor size, lymph node metastasis, advanced stage, and non-surgical management were independent predictors of worse DSS. Patients diagnosed in 2013-2022 showed better DSS compared with those in 2004-2012 (64.7% vs. 52.0%, p = 0.048). CONCLUSION: SDC incidence has increased rapidly, possibly reflecting improved diagnostic recognition and reclassification, with only modest survival improvement over the past decade.