Abstract No. 234 Long-Term Survival After Percutaneous CT and Contrast-Enhanced Ultrasound-Guided Microwave Ablation of Pathologically Proven Renal Cell Carcinoma

To determine the technical success (TS), long-term overall survival (OS), cancer-specific survival (CSS), and local tumor progression free survival (LTPFS) of patients who underwent percutaneous microwave ablation (MWA) of pathologically proven clear cell (ccRCC) and non-clear cell (nccRCC) renal cell carcinoma (RCC). This institutional review board–approved, HIPAA-compliant study cohort (SC) included all patients who underwent percutaneous CT and contrast-enhanced ultrasound (CEUS)-guided MWA between 2013 and 2017 of biopsy-proven RCC. Patient demographics, tumor characteristics, procedural technical outcomes, and pre- and post-procedural estimated glomerular filtration rate (eGFR) were compiled and the TS, OS, CSS, and LTPFS were derived with Kaplan-Meier analysis and log-rank test to evaluate differences. Complications were classified per the Clavien-Dindo system. Logistic regression was used for categorical outcomes accounting for repeated measures at the lesion level, chi-square test was used for categorical outcomes excluding repeated measures at the patient level, and paired t-test was used for evaluating differences in eGFR. The SC comprised 86 biopsy-proven RCCs (38/86 (44%) clear cell RCC) from 81 patients (mean age: 67.6 (28–94 years); men 62%) with a median follow-up of 76.8 months (1 to 123 months). Overall, primary (one session) and secondary (two sessions) TS were 100% (86/86), 88.4% (76/86) and 90% (9/10), respectively. The 5-year and 10-year OS, CSS, and LTPFS rates were 82.7% and 75.7%, 90.8% and 84.7%, and 84.3% and 82.9%, respectively. The T1b subcohort 8-year OS and LTPFS rates were lower compared to T1a subcohort (p=0.064, 0.005, respectively). RCC lesions > 4 cm was predictive of LTPFS (p=0.016). The 8-year OS, CSS, LTPFS rates for the ccRCC and nccRCC subcohort were similar (p=0.47, 0.21, 0.64, respectively). The pre-ablation and 2-3 year post-ablation eGFR (58.5 vs 58.4 mL/min/1.73 m2 were stable (p=0.932). There was a 2% overall incidence of complications, all grade I. Percutaneous CT and CEUS-guided MWA of biopsy-proven ccRCC and nccRCC was safe and effective with excellent long-term OS, CSS, and LTPFS outcomes within 10 years from initial treatment for T1a and T1b lesions.