Percutaneous Cryoablation of Clinical T1b Renal Tumors: A Tertiary Cancer Center Experience

PURPOSE: To evaluate the oncologic and survival outcomes of patients who underwent cryoablation (CA) for T1b renal masses. MATERIALS AND METHODS: This retrospective observational cohort study was conducted in accordance with the STROBE guidelines. All patients with renal tumors from 4.1 cm to 7 cm in our renal ablation registry who underwent CA between January 2008, and June 2024 were included in our study. We excluded patients with renal tumors < 4 cm and patients who underwent microwave or Radiofrequency ablation, for T1b lesions. We compiled data on age, sex, tumor location and size, histopathology, procedure-related variables, and outcomes. The Kaplan-Meier methodology was used to estimate survival probabilities. RESULTS: Fifty-one patients underwent 52 CA for 51 renal tumors. Overall, 39% of patients had a concomitant non-renal malignancy. The median tumor diameter was 4.5 cm. The median RENAL nephrometry score was 5. Most tumors (82%) were proven to be RCC by biopsy. Twenty-three patients underwent only cryoablation and 28 underwent a combination of embolization and cryoablation. Two patients (4%) experienced recurrence at the ablation site (30 months and 41.5 months after the ablation). Among the 27 patients with de novo histologically proven renal cell carcinoma included in the survival analysis, the median overall survival duration was 6.1 years, and the 5-year Local recurrence, disease and metastatic free survival rates were 87%, 83%, and 96%, respectively. CONCLUSION: CA (with and without embolization) is safe and effective in patients with clinical T1b RCC who are not candidates for surgery. Cryoablation offers durable local oncologic control and favorable long-term survival outcomes in appropriately selected patients.