Oncological outcomes of active surveillance and percutaneous cryoablation of small renal masses are similar at intermediate term follow-up

BACKGROUND: Active surveillance (AS) and minimally invasive ablative therapies such as percutaneous cryoablation (PCA) are emerging as alternative treatment modalities in the management of small renal masses (SRMs). METHODS: Fifty-nine patients underwent PCA since 2011 and 75 underwent AS since 2010 at two different institutions. Only patients with follow-up ≥6 months were included. All patients were followed with a standardized protocol. Treatment failure was defined by dimensional progression for AS and renal recurrence for PCA, in addition to stage and/or metastatic progression for both groups. RESULTS: Treatment failure was observed in 14 cases (18.7%) during AS (mainly due to dimensional progression) and 12 patients (16%) underwent delayed intervention with a mean follow-up of 36.83 months. Seven patients (11.9%) in the PCA group experienced treatment failure with a mean follow-up of 33.39 months and three of them underwent re-ablation successfully. Cancer-specific-survival at 2 and 5 years was 100% and 95,8% in AS-group vs. 98.2% and 98.2% in PCA-group (P=0.831). One patient in both groups died from metastatic disease. Overall-survival at 2 and 5 years was 91.7% and 82.4% in the AS group vs. 96.5% and 96.5% in the PCA group (P=0.113). Failure-free survival at 2 and 5 years was 90.9% and 70.1% in the AS group vs. 93.1% and 70.9% in the PCA group (P=0.645). CONCLUSIONS: AS and PCA provide similar survival outcomes and are safe and valid treatment options for elderly and comorbid patients with SRMs.