Renal cell carcinoma with venous tumor thrombus in young adults: Distinct clinicopathological features and shorter progression-free survival

Objectives: This study aimed to characterize the clinicopathological features and survival outcomes of young patients with renal cell carcinoma and venous tumor thrombus (RCC-VTT). Materials and Methods: We retrospectively reviewed 468 patients with RCC-VTT who underwent radical nephrectomy and thrombectomy at a high-volume center. Patients were classified as young (≤40 years, n = 43) or older (>40 years, n = 425). Propensity score matching and overlap weighting were used to improve intergroup comparability. Kaplan–Meier analysis and Cox regression were used to evaluate survival outcomes and prognostic associations. Results: Compared with older patients, young patients had larger tumors, more frequent enlarged lymph nodes, more advanced T stages, and greater perioperative transfusion requirements. They also exhibited distinct histological profiles, with higher proportions of papillary RCC and molecularly defined subtypes. Young age was associated with shorter progression-free survival (PFS) in the unadjusted analysis (hazard ratio, 1.79; 95% confidence interval, 1.19–2.70) and remained associated with shorter PFS after accounting for measured clinicopathological characteristics. Across multivariable modeling approaches, young age was consistently retained in the PFS models, together with established prognostic factors, including distant metastasis and nuclear grade. Conclusions: Among patients with RCC-VTT undergoing surgical treatment, young patients exhibited distinct clinicopathological characteristics and shorter PFS. These findings suggest that age-related prognostic differences may not be fully explained by conventional clinicopathological characteristics and warrant further biological investigation.