Percutaneous Cryoablation of Renal Tumors: Is It Time for a New Paradigm Shift?

PURPOSE

To retrospectively assess long-term outcomes of percutaneous renal cryoablation, including factors affecting complications and local recurrence rates.

MATERIALS AND METHODS

A total of 357 computed tomographic (CT) fluoroscopy-guided percutaneous cryoablation procedures were performed for 382 masses in 302 outpatients; 347 were biopsy-proven renal-cell carcinoma (RCC) or Bosniak category > III masses (n = 28). Benign pathologic conditions (n = 18) or metastatic non-RCC disease (n = 17) were included to analyze procedural complication rate, but recurrence rates, tumor staging, and nephrometry score were limited to RCCs. The average tumor diameter was 2.9 cm (range, 1-10.3 cm), and median nephrometry score for RCC was 8 (mean, 7.4). Protection of adjacent vital structures was performed in 34% of procedures (n = 121), and ureteral stent placement was performed for 9.2% (n = 33). All major complications were graded per surgical Clavien-Dindo criteria.

RESULTS

The average CT-visible cryoablation zone diameter was 5 cm (range, 2.5-10.5 cm). Grade ≥ 3 complications occurred in 2.8% of procedures (n = 10), and appeared related to only high nephrometry scores (P = .0086) and larger tumors (P = .0034). No significant changes in renal function before and after the procedure were noted (P = .18). At a mean follow-up of 31.8 months, the local tumor recurrence rate was 3.2% (11 of 347) for RCC, and no significant difference was noted between tumors larger or smaller than 3 cm (P = .15). The difference reached significance only among the small number of stage ≥ T2 RCC tumors (P = .0039).

CONCLUSIONS

Long-term follow-up of percutaneous renal cryoablation demonstrates low recurrence rates with preserved renal function, even for patients with high nephrometry scores and body mass index, assuming thorough cytotoxic technique and protection measures.