Contemporary analysis of epididymal tumors using a national database.

INTRODUCTION: Epididymal tumors are rare malignancies with sparse research available to guide recommendations. We sought to characterize malignant epididymal tumors in the United States using population level data. MATERIAL AND METHODS: The Surveillance, Epidemiology, and End-Results database was queried for patients diagnosed with malignant epididymal tumors between 1975-2016. International classification of disease for oncology code C63.0 was used to identify population with disease of interest. Primary objective was to characterize patient demographics, disease characteristics, and management. Secondary objectives included overall and cancer-specific survival (CSS) utilizing Kaplan-Meier (KM) analysis. RESULTS: A total of 66 cases of malignant epididymal tumors were identified during the study period. The cohort was largely white (84.8%), with a mean age of diagnosis of 46.9 years old. The predominant histology consisted of rhabdomyosarcoma 26%, leiomyosarcoma 23%, liposarcoma 17%, adenocarcinoma 9%, and malignant fibrous histiocytoma 5%. During histopathological assessment, 21.1% of tumors were classified as high-grade while 71.2% exhibited sarcomatoid elements. Majority of patients presented with localized disease (68.2%), whereas regional (18.2%) and distant (13.2%) disease was less frequently discovered. All patients were diagnosed by surgical therapy consisting of radical epididymectomy (39.4%), partial epididymectomy (27.3%) or 'unknown surgery' (33.3%). Meanwhile, 15.2% and 34.8% received radiation and chemotherapy, respectively. KM analysis revealed an 84.9% CSS at 5-years. Over 60% of documented cases have arisen since 2000, with 3.0% of the cohort diagnosed in 2016, increased from 1.5% of the diagnoses in 1975. CONCLUSIONS: Malignant epididymal tumors are exceedingly rare and typically present with localized disease. Surgical excision is associated with an estimated 85% CSS at 5-years.