135 Comparative analysis of Clear cell and non-clear cell renal cell carcinoma in Patients Under 40

Introduction/Objective Renal cell carcinoma (RCC) is among top 10 malignant neoplasms in the USA. The median age of diagnosis is 65 years; however, increased cases are being diagnosed in younger patients. This study compares outcome in RCC subtypes in patients under 40. Methods/Case Report Institutional database was searched for RCC cases in patients under 40 years, from 2020-2024. Pediatric cases of Wilms tumor were excluded. Results 67 cases (39 male, 28 female) were identified. Mean age was 32.7±7 years. Clear-cell RCC was the most common subtype, with 44(65.7%) cases. Chromophobe RCC accounted for 8(11.9%), papillary RCC 5(7.5%) and TFE3-rearranged RCC 2(3%). SDH-deficient RCC, FH-deficient RCC and tubulocystic RCC had one case each. Six(8.9%) cases were unclassified-RCC. All patients of clear-cell RCC remained alive, with follow-up ranging from 7-43 months. Among non-clear cell RCC 20 patients remained alive with follow-up ranging from 8-57 months, while three patients died within 3 years of initial diagnosis. Clear cell RCC was associated with significantly favorable prognosis compared to non-clear cell RCC subtypes (χ²=11.386, P < 0.001). Conclusion Clear cell RCC remains most prevalent subtype even among young individuals and is associated with favorable prognosis. Molecularly defined and unclassified RCC accounted for 15% cases with a subset following aggressive clinical course.