Testicular Mesothelioma: An Analysis of Epidemiology, Patient Outcomes, and Prognostic Factors.

OBJECTIVES: To characterize demographic features, clinical characteristics, and oncologic outcomes of mesothelioma of the testis.

METHODS: A population based search was performed using the National Cancer Institute's SEER 18 database. Patients diagnosed with malignant mesothelioma of the male genital organs from 1973 to 2015 were identified. Data on patient age, race, tumor laterality, histologic subtype, tumor extent, tumor size, tumor grade, treatment, cause of death, and survival months was collected. Primary outcomes were overall survival (OS) and disease-specific survival (DSS).

RESULTS: A total of 113 patients with testicular mesothelioma were identified. The 5-year OS and DSS for all patients was 49% and 58%, and the 10-year OS and DSS was 33% and 45%, respectively. Biphasic mesotheliomas were associated with worse OS compared to general mesotheliomas and epithelioid subtypes (P = .043 and P = .039, respectively). Median survival time was not reached in patients with T1 disease while OS was 1.7 years and DSS was 1.8 years for patients with T4 disease (OS P = .002, DSS P <.001). Tumors greater than or equal to 4 cm were associated with worse OS and DSS (OS P = .025, DSS P = .047).

CONCLUSION: This rare malignancy has significant mortality, with poor survival associated with biphasic subtypes, higher disease stage, and a critical tumor size cutoff of 4 cm.