Characteristics and clinical outcomes of metastatic testicular cancer in a distinct demographic.

620 Background: Testicular cancer is the most common malignancy among adolescent and young adult (AYA) males (15 – 40 years). While the median age at diagnosis is 33 years, testicular cancer also occurs in older aged males (>40 years). Though it is less frequent in this population, it is important because outcomes of metastatic testicular cancer in this population are unknown. We examined the inpatient characteristics and outcomes for older patients with a diagnosis of metastatic testicular cancer. Methods: In a retrospective cohort analysis using the NIS database from 2008 to 2021, admitted patients with metastatic testicular cancer were identified using ICD codes. Descriptive analyses were conducted to compare sociodemographic, hospital-level and clinical characteristics between the older population and the AYA. Multivariate logistic and linear regression models were used to examine the association between the age groups and mortality, length of stay (LOS), and total hospital charges (THC). Results: There were 57,366hospitalizations with metastatic testicular malignancy. Of these, 14,733 (25.7%) were in the older male cohort. The mean age was 51 years in the older group and 27.3 years in the AYA group (P < 0.001). There was a higher proportion of non-Hispanic White patients in the older group compared to the AYA group (73% vs 53%, P < 0.001) but a lower distribution of Hispanic patients (11% vs 31%, P < 0.001). Most of the patients in both cohorts had private insurance (54% vs 47%, P<0.001). Both groups had most admissions in teaching (75.7% vs 84%, P < 0.001), urban (95.2 vs 97.2%, P<0.001), andlarge-sized hospitals (65.5 vs 70%, P=0.001). HIV comorbidity was higher in the older population (0.5% vs 0.2%, P = 0.02). The mortality rate was higher in the older population compared to the AYA population (6.2% vs 2.8%, P < 0.001). The older group had over two-fold higher odds of mortality relative to the younger adult group (aOR: 2.25, 95% confidence interval [CI]: 1.84-2.75, P < 0.001). On subgroup analysis, black patients had 70% higher mortality relative to non-Hispanic White patients (aOR: 1.7, 95% CI 1.15-2.5, p=0.008). There was a longer LOS in the older group (β coefficient: 0.49, 95% CI: 0.15-0.84, P = 0.005). THC were similar between the two cohorts (β-Coefficient: 1,238, 95% CI: -4,080–6,555, P = 0.65). The older group were less likely to have retroperitoneal lymph node dissection (aOR: 0.57, 95% CI: 0.48-0.67, P<0.001). Conclusions: This is the largest epidemiological study to date on metastatic testicular cancer hospitalizations in older adults. Older males with metastatic testicular cancer have higher odds of mortality relative to younger patients. Racial disparities were evident, with Black patients having higher mortality. Our findings underscore unique characteristics and outcomes that could guide patient selection for future clinical trials and enhance the development of novel therapies for this population.