Survival of Testicular Pure Teratoma vs. Mixed Germ Cell Tumor Patients in Primary Tumor Specimens across All Stages

SIMPLE SUMMARY: Previous analyses from referral centers of testicular cancer investigated the prognostic impact of presence of teratoma components in advanced testicular primary tumor specimens and observed conflicting results. However, data investigating pure teratoma in primary tumor specimens is limited and the prognostic impact is uncertain. To address this void, we tested for overall survival differences and subsequently, differences in cancer-specific and other-cause mortality in pure teratoma vs. mixed germ cell tumor patients. ABSTRACT: We aimed to test for survival differences between testicular pure teratoma vs. mixed germ cell tumor (GCT) patients in a stage-specific fashion. Pure teratoma and mixed GCT in primary tumor specimens were identified within the Surveillance, Epidemiology, and End Results database (2004–2019). Kaplan–Meier curves depicted five-year overall survival (OS) and subsequently, cumulative incidence plots depicted cancer-specific mortality (CSM) and other-cause mortality (OCM) in a stage-specific fashion. Multivariable competing risks regression (CRR) models were used. Of 9049 patients, 299 (3%) had pure teratoma. In stage I, II and III, five-year OS rates differed between pure teratoma and mixed GCT (stage I: 91.6 vs. 97.2%, p < 0.001; stage II: 100 vs. 95.9%, p < 0.001; stage III: 66.8 vs. 77.8%, p = 0.021). In stage I, survival differences originated from higher OCM (6.4 vs. 1.2%; p < 0.001). Conversely in stage III, survival differences originated from higher CSM (29.4 vs. 19.0%; p = 0.03). In multivariable CRR models, pure teratoma was associated with higher OCM in stage I (Hazard Ratio (HR): 4.83; p < 0.01). Conversely, in stage III, in multivariable CRR models, pure teratoma was associated with higher CSM (HR: 1.92; p = 0.04). In pure teratoma, survival disadvantage in stage I patients relates to OCM. Survival disadvantage in stage III pure teratoma originates from higher CSM.