Intermediate-term outcomes after renal cryoablation: Results of a multi-institutional study

Purpose: To present intermediate-term oncologic efficacy of cryoablation (CA) for the treatment of patients with small renal masses in a multi-institution multisurgeon cohort. Patients and Methods: We retrospectively reviewed billing records and tumor registries, identifying 116 renal tumors in 116 patients treated with CA by six surgeons at four institutions. Patient age, sex, tumor size, RENAL nephrometry score, complications, and recurrences were recorded. Results: One hundred-sixteen patients (66.4% male, 33.6% female) with 116 tumors underwent renal mass CA with a mean follow-up of 27.4 months (range 1-112mos). Mean tumor size was 2.76±0.97cm (range 1.1-5.5cm). Twenty-seven complications occurred in 23 patients for an overall complication rate of 19.8%. Low-grade complications (Clavien I and II) accounted for 92.6% (n=25) of overall complications. Seven (6%) patients had enhancement on initial imaging and were considered incomplete ablations. Local recurrence and metastatic disease developed in four and one patients, respectively. In patients with biopsy-proven renal-cell carcinoma (RCC), the 2- and 5-year recurrence-free survival (RFS) probability was 0.83 (95% confidence interval [CI]: 0.74, 0.95) and 0.77 (95% CI: 0.60, 0.94), respectively. After excluding biopsy proven RCC patients with incomplete ablations, the 2- and 5-year RFS increased to 0.91 (95% CI: 0.82, 1.00) and 0.85 (95% CI: 0.71, 1.00) respectively. Conclusion: CA of renal masses results in acceptable oncologic efficacy accompanied by a tolerable complication profile in a cohort with a mean follow-up of 27.4 months. CA remains a viable treatment option for small renal masses in selected patients.