Percutaneous tumor ablation versus partial nephrectomy for small renal mass: the impact of histologic variant and tumor size

BACKGROUND: To investigate recurrence rates in patients with T1 renal cell carcinoma (RCC) undergone partial nephrectomy (PN), radiofrequency ablation (RFA) or cryoablation (Cryo).METHODS: We retrospectively evaluated data from 665 (81.4%), 68 (8.3%) and 83 (10.3%) patients who underwent PN, RFA and Cryo, respectively. Kaplan-Meier curves depict recurrence-free survival (RFS) rates in the overall population and after stratifying according to tumor's histology (namely, clear cell RCC and non-clear RCC) and size (namely < 2 cm and 2-4 cm). Multivariable Cox regression model was used to identify predictors of recurrence. Cumulative-incidence plots evaluated disease recurrence and other causes of mortality (OCM).RESULTS: Patients referred to PN experienced higher RFS rate compared to those treated with RFA and Cryo at 60-month in the overall population (96.4% vs. 79.4 % vs. 87.8%), in patients with clear cell RCC (93.3% vs 75% vs. 80.4%) and in those with tumor of 2-4 cm (97.3% vs 78% and 84.4%; all p≤0.01). In patients with non-clear cell RCC and with tumor <2cm, PN showed higher RFS rate at 60-month as compared to RFA (97.9% vs 84.4% and 95.1% vs 78.1%, respectively; all p≤0.02). At multi-variate analysis, ablative techniques (RFA [HR=4.03] and Cryo [HR=3.86]) were independent predictors of recurrence (all p<0.03). At competing risks analysis, recurrence rate and OCM were 7.3% and 1.3% vs 25% and 7.2% vs 19.9% and 19.9% for PN, RFA and Cryo, respectively.CONCLUSIONS: PN and Cryo showed similar RFS rates in patients with non-clear cell RCC and with renal mass < 2cm.