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 3 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.