Abstract No. 231 Long-Term Survival After Percutaneous Image-Guided Ablation of Oligometastatic Renal Cell Carcinoma

To determine the long-term overall (OS), cancer-specific (CSS), and local tumor progression-free survival (LTPFS) of patients who underwent percutaneous cryoablation (CA), microwave ablation (MWA), or radiofrequency ablation (RFA) of metachronous oligometastatic renal cell carcinoma (omRCC). This institutional review board–approved, HIPAA-compliant study retrospective cohort included patients who underwent percutaneous ablation between 2008 and 2017 of omRCCs. Patient demographics, tumor characteristics, and procedural technical outcomes were evaluated. Technical success, OS, CSS, and LTPFS were assessed through immediate and follow-up imaging. Kaplan-Meier survival analysis was performed. Complications were classified per the Clavien-Dindo system. The study cohort comprised 100 omRCCs from 50 patients (mean age: 65 years ranging from 32 to 86 years). CA, MWA, and RFA were performed on 35%, 43%, and 22% of lesions, respectively, with a median follow-up period of 92 months (1 to 177 months) and mean tumor size of 1.8 cm (0.4 to 4.7 cm). The omRCC lesion sites included lung (n=35), mediastinum (n=2), ipsilateral kidney (n=13), contralateral kidney (n=31), adrenal gland (n=5), spleen (n=7), liver (n=1), and retroperitoneum (n=6). Primary technical success based on immediate post-procedure imaging was achieved for 100/100 (100%) omRCC tumors. Local tumor recurrence was found on follow-up imaging omRCC tumors in 12/100 (12%) with median time to recurrence of 12 months and 5 tumors were retreated successfully. The 5-year OS, CSS, and LTPFS rates were 88.0%, 89.9%, and 88.0%, respectively. The 10-year OS, CSS, and LTPFS rates were 68.6%, 74.0%, and 88.0%, respectively. There were 10 (13%) procedure-related complications including eight high-grade events which required radiological interventions (Clavien-Dindo III). Percutaneous image-guided CA, MWA, and RFA of metachronous omRCC were safe and effective with excellent long-term OS, CSS, and LTPFS outcomes.