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

BACKGROUND

The aim, of this study was 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.