Percutaneous Cryoablation for Small Renal Masses in a High-Risk Cohort: Oncologic and Functional Outcomes from a 5-Year Single-Center Experience

Introduction: Percutaneous cryoablation (CA) is increasingly used to manage small renal masses (SRMs) in selected patients, offering a nephron-sparing, minimally invasive alternative to surgical resection. We evaluated the safety, renal functional preservation, and short-term oncologic outcomes of CA in a high-complexity cohort at a tertiary referral center. Materials and Methods: We conducted a retrospective single-center analysis of consecutive patients treated with CA between 2020 and 2025. SRMs were defined as renal tumors ≤4 cm (cT1a). Procedures were performed under local anesthesia, primarily using combined ultrasound and cone-beam computed tomography guidance. Primary outcomes included perioperative morbidity (Clavien-Dindo) and oncologic results (local failure, metastasis, and cancer-specific survival). Secondary outcomes focused on renal function preservation (eGFR). Results: Seventy-one patients were included in the analysis. The cohort had a median age of 70 years and a high comorbidity burden, with a median Charlson Comorbidity Index of 5; prior renal surgery was present in 45% of patients and 13% a solitary kidney. All procedures achieved technical success. The overall complication rate was 20%, with no Clavien-Dindo grade ≥II complications. At a median follow-up of 10 months, early oncologic outcomes showed 11 patients with local failure (9 patients with residual disease, 2 patients with recurrence), reflecting the high proportion of “salvage” cases. Most failures (55%) were successfully managed with repeated CA. Metastatic progression occurred in 3% of cases, and cancer-specific mortality was 1.4%. Median eGFR decline was 2.5 mL/min/1.73 m². Conclusions: CA represent a safe and effective nephron-sparing strategy for selected patients with SRMs, particularly in high-complexity cases. Despite a non-negligible local failure rate in salvage cases, CA allows effective disease control while preserving renal function. These findings support CA as a valuable treatment option, although longer follow-up is needed to confirm long-term oncologic durability.