196 - Comparing Volumetrics for Predicting Adverse Events and Local Recurrence After Percutaneous Ablation of Renal Cell Carcinoma

Purpose: This study aims to assess tumor diameter and volume as predictors of major adverse events (AEs) and local recurrence following PA for RCC.

Materials and Methods: In this single-center retrospective study, patients undergoing PA for RCC from January 2008 to December 2023 were included in the analysis. Data collection included patient demographics, medical co-morbidities, and pre-procedure laboratory values. Tumor characteristics, including diameter and volume, were obtained from pre-procedural imaging. Technical success, local recurrence, and AEs were recorded. Statistical analyses included t-tests, Mann-Whitney U tests, and multivariate logistic regression. Adverse events were classified using SIR criteria, and overall and cancer-specific survival analyses were conducted using the Kaplan-Meier method.

Results: 203 patients with 207 unique tumors (mean diameter: 30.1 mm; mean volume: 16,959 mm³) were included in the study. Major AEs occurred in 14 patients (6.8%), and local recurrence was observed in 13 patients (6.3%). Tumors associated with major AEs had significantly larger mean diameters (43 mm vs. 29.2 mm, p< 0.001) and mean volumes (35,580 mm³ vs. 15,667 mm³, p< 0.001) than those with minor/no adverse events. However, tumor size and volume did not significantly differ between patients with or without recurrence (p=0.06 and p=0.09, respectively). In multivariate analysis, only diameter size (OR: 6.4, 95% CI (1.5, 32.3), p=0.015) and pre-procedural INR (OR: 1.5, 95% CI (1.0, 2.4), p=0.03) were independent predictors of major AEs. No variables were found to be independently predictive of local recurrence.

Conclusion: Both tumor diameter and volume were found to have an increased risk of major AEs after PA, however, only diameter remained an independent predictor in multivariate analysis. Neither tumor volume nor tumor diameter were found to be predictive of local recurrence. Despite technological advancements, this study supports the continued clinical utility of tumor diameter as a reliable predictor of adverse outcomes in renal tumor ablation, aligning with prior nephrometry-based findings. Although tumor volume has emerged as a promising predictive measure in multiple treatment modalities, it does not independently enhance risk stratification in PA for RCC. These findings may aid physicians by providing for a more accurate evaluation of tumor burden, ultimately improving pre-procedural risk assessment and patient counseling.