Percutaneous Cryoablation of Renal Tumors Shows Benefit After Long-Term Follow-up

Over the long term, patients who received percutaneous renal cryoablation had low recurrence rates with preserved renal function, according to a study published in the Journal of Vascular and Interventional Radiology. The low recurrence rates and preserved renal function were seen even in patients with high BMI and nephrometry scores as long as proper protection measures were taken.

The retrospective study evaluated data from 357 computed tomographic (CT) fluoroscopy-guided percutaneous cryoablation procedures that were performed for 382 masses in 302 outpatients. Of the procedures, 347 were biopsy-proven renal-cell carcinoma (RCC) or Bosniak category > III masses. The median nephrometry score for RCC was 8, and the tumor diameter average was 2.9 cm. In 34% of procedures, adjacent vital structures such as the bowel and ureter were protected from cytotoxic freezing temperatures. In 9.2% of procedures, a ureteral stent was placed to protect the ureter.  

After the procedures, measurements of the overall ablation zone were taken in three dimensions on follow-up imaging. Results indicated that, on average, there was a cryoablation zone diameter of 5 cm visible on CT imaging.

The local recurrence of rate was 3.2% after a mean follow-up of 31.8 months, and the investigators observed no significant difference between tumors larger or smaller than 3 cm. “The difference reached significance only among the small number of stage ≥ T2 RCC tumors,” the investigators stated.

Only 2.8% of procedures had Grade ≥ 3 complications, and these seemed to be linked to high nephrometry scores and larger tumors. There were no significant changes in renal function prior to and after the procedure.

“The present study had high primary and secondary efficacy rates of 96.8% and 99.4%, respectively, for percutaneous renal mass ablation,” the study’s authors wrote. They added, “The low recurrence rates in the present series are comparable to the outcomes of other cryoablation series and partial nephrectomy series.”

The retrospective design of the study and the lack randomization or a control arm were limiting factors for the study, the authors acknowledged, but the long-term data “confirms that cryoablation is a safe and highly efficacious alternative for the treatment of RCC with similar local and distant outcomes as partial nephrectomy, but with near-complete preservation of renal function,” they concluded.

Reference

Aoun HD, Littrup PJ, Jaber M, et al. Percutaneous Cryoablation of Renal Tumors: Is It Time for a New Paradigm Shift? J Vasc Interv Radiol. 2017;28(10):1363-1370.