Cool trend in IR practice looks for warm reception

The hottest trend in interventional radiology is also its coldest. Improved technology and growing clinical experience have moved cryoablation into mainstream IR practice.

Cryoprobes used to be too large to allow perutaneous intervention. But Endocare (Irvine, CA) recently introduced a 1.7-mm diameter device about one-quarter the size of the previous generation. The industrial leap has made percutaneous image-guided cryoablation possible, said Dr. J. Louis Hinshaw, an interventionalist and assistant professor of abdominal imaging at the University of Wisconsin-Madison.

Hinshaw and colleagues compared percutaneous and laparoscopic cryoablation in 67 patients with renal tumors. Although their study design did not allow a clear-cut assessment, percutaneous cryotherapy came out looking just as safe and more cost-effective than the laparoscopically guided version. They presented results at the 2007 Society of Interventional Radiology meeting.

Mayo Clinic investigators recently published results from 40 patients who underwent percutaneous cryoablation for renal cell carcinomas. They obtained 95% technical success and encountered a 3% complication rate for tumors with a mean size of 4.2 cm (AJR 2007;188:1195-1200).

Cryoablation offers precision compared with radiofrequency or microwave ablation. It can control the size and shape of the iceball when guided by CT, ultrasound, or MR. It is not widely known outside tertiary-care centers, however, and the equipment requirements make it cumbersome compared with the small RFA and MWA generators.

The introduction of a new pressurized liquid nitrogen technology promises larger ablations with smaller probes could change that. Cryotherapy has proved its value for the treatment of painful bone metastases and is drawing attention in lung cancer treatment.

Long-term randomized trials comparing all ablative techniques will define their appropriate clinical utilization, Hinshaw said.