Understanding incidence and outcomes of testicular and ovarian germ cell tumors from 2000–2017 using population-based cancer registries.

Abstract

649 Background: Both testicular (TGCT) and ovarian germ cell tumors (OGCT) originate from a common primordial germ cell lineage prior to differentiation into sperm or eggs and share several features. While TGCT are extensively studied, less is known about OGCT but given the relative rarity of both TGCT and OGCT, we aimed to comprehensively assess the current landscape of these diseases using population-based cancer registries that surveil the entire civilian population of the US. Importantly, this analysis includes all data from 2000 to 2017 and is therefore not subject to the impacts on cancer data reporting during the COVID-19 pandemic in the US. Methods: We accessed population-based data available from the year 2000 forward from Surveillance, Epidemiology, and End Results (SEER) and National Program of Cancer Registries (NPCR) registry networks to obtain information about incidence and outcomes of TGCT and OGCT. NPCR+SEER was utilized to characterize nation-wide patterns of incidence according to demographic features and histologic type, SEER21 to describe age-specific patterns, SEER18 to describe outcomes and SEER9 to describe long-term patterns of age-specific incidence according to year of diagnosis and year of birth. Detailed descriptive analysis were performed. Age-adjusted incidence rates (AAIRs) and temporal trends were calculated overall and stratified by race/ethnicity and histology. Observed and relative survival were also assessed overall and according to race/ethnicity and histology. Results: TGCTs were far more common than OGCTs and the majority of all GCTs occurred in adolescents and young adults. The AAIRs of TGCT were greatest in NH white men and for OGCT, greatest in Hispanic White women. Seminoma was the most common histology in TGCT, and dysgerminoma was most common in OGCT. For TGCT, the most drastic increases in incidence were noted in Hispanic and American Indian/Alaska Native men, whereas incidence was relatively stable in non-Hispanic white men. For OGCT, incidence was relatively similar amongst racial/ethnic groups. We also found that observed survival in Black men with TGCT is worse than all other racial/ethnic groups, but relative survival is comparable. A similar and more pronounced finding was seen in OGCT, but Black women experienced both worse observed and relative survival compared to the other groups. Regarding histology, those with seminoma or dysgerminoma had better survival than those with NSGCT/non-dysgerminoma. Conclusions: We present a contemporary and comprehensive assessment of incidence and outcomes of TGCT and OGCT for the entire US civilian population from 2000-2017, that is not subject to impacts of cancer reporting during the COVID-19 pandemic. We identified various racial/ethnic differences in incidence and survival both within and between TGCT and OGCT, which highlights opportunities to intervene.