Background: Testicular germ cell tumors (TGCTs) is the leading solid-organ malignancy of adolescent/young adult males. Incidence is rising in all racial/ethnic groups, and most rapidly in Hispanics, who tend to be younger than non-Hispanic white (NHW) patients at diagnosis yet have poorer survival. Understanding these disparities is an urgent research priority, but granular prognostic information is inadequate in large population-based registries. We therefore initiated an investigation of a largely Hispanic clinical cohort. Methods: We identified consecutive patients with pathologically confirmed TGCT treated from 2015 to 2020 at two major referral centers in the US, with a large Hispanic population (the Los Angeles General Medical and USC/Norris Comprehensive Cancer Centers) and collected detailed features of demography, clinical presentation, treatment, and outcome into a structured RedCAP database. We used chi-square, Fisher exact, and Mann-Whitney U tests to compare established prognostic features between Hispanic and NHW patients. Results: Among 27 NHW and 75 Hispanic patients, Hispanics were younger at diagnosis (median 27 vs 30 years, p=0.5), diagnosed less frequently with pure seminoma (12% vs 23%, p=0.19), and experienced shorter time to first progression (median 8.5 vs 19 months, p=0.6). Among non-seminoma patients, Hispanics had higher probability of IGCCCG intermediate risk (26% vs 0%, p=0.03) but similar frequency of poor risk disease (Table). Accordingly, Hispanics had more regional lymph node involvement at presentation (48% vs 19%, p=0.03) but comparable frequency of visceral metastasis. Conclusions: Hispanic patients had adverse features already evident in population-based data, and novel findings of higher risk stratification and greater lymph node involvement than NHWs. Expansion of clinical series will be vital to identifying factors and processes that underlie adverse presentation and outcomes of Hispanics with TGCT, and to refining guidelines for care of the growing population of Hispanic patients with TGCT.

^a3 had missing data. ^bIGCCCG risk category. ^cComparing histology between Hispanic and NHW patients. ^dComparing risk category within histology.