Real-world clinical and toxicity outcomes in older Veterans with metastatic renal cell carcinoma (mRCC) treated with front-line systemic therapy.

e16525 Background: The United States veteran population represents a unique group of patients with distinct health care challenges, particularly for older veterans. Here, we describe a real-world cohort of veterans with mRCC treated with systemic therapy and assess if outcomes and toxicities with front-line systemic therapy differ for older adult veterans. Methods: Veterans diagnosed with mRCC between 2010- 2023 at the Richard L. Roudebush VA in Indianapolis and treated with front-line systemic therapy were identified. Patients were classified as £65yo and >65yo. Comparisons between groups were done using Chi-square tests for categorical variables or Wilcoxon test for continuous variables. Kaplan-Meier method was used to analyze progression-free survival (PFS) and overall survival (OS), with Cox model used to adjust for confounders. Results: A total of 73 patients with mRCC were identified. Median age was 67.4. 31 patients (42%) were £65yo and 42 (58%) were >65. 99% of patients were male. 69% of patients had clear cell histology, 11% papillary, 11% poorly differentiated, 5% unclassified, 2% chromophobe, 2% sarcomatoid, and 2% other. 52% of patients ≤65yo had IMDC int/poor risk disease vs. 85% of patients >65 (p=0.016). There was no statistically significant difference in disease grade, stage, or presence of sarcomatoid/rhabdoid features between groups. The table lists and compares therapies received and toxicity outcomes. The median PFS was 18.7 months in pts ≤65yo vs. 7.1 months in pts >65 (p=0.24). The median OS was 58.1 months in pts ≤65 vs. 12.6 months in pts >65. (p=0.048). When using the Cox model to adjust for IMDC risk, the OS difference was not maintained, with a hazard ratio of 1.16 (CI 0.59, 2.27; p=0.664). Conclusions: In this cohort of veteran patients with mRCC, older veterans had higher rates of IMDC int/poor risk disease, likely leading to decreased survival outcomes. Front-line systemic therapies used were similar to younger veterans without an apparent difference in toxicity. This material is the result of work supported with resources and the use of facilities at the Richard L. Roudebush VA in Indianapolis. [Table: see text]