Turning kidney tumours into an ice ball using minimally-invasive, image-guided cryoablation appears to result in less recurrence of cancer, shorter time in hospital and less expense, researchers reported here at the 32^nd scientific meeting of the Society of Interventional Radiology (SIR).

"This early-stage research indicates that percutaneous cryoablation in the appropriate patient population can effectively kill tumours and an excellent safety profile, all at a lower cost than laparoscopy," said J. Louis Hinshaw, MD, assistant professor of radiology, University of Wisconsin Medical School, Madison, Wisconsin, United States.

Dr. Hinshaw and colleagues compared 19 percutaneous procedures against 48 laparoscopic cryoablation procedures.

Results showed a tumour recurrence rate of 12.5% for patients who underwent laparoscopic procedures and 10.5% for those who underwent percutaneous cryoablation (P < .05).

Percutaneous cryoablation required an average of 1.1 days in hospital compared with 2.5 days for laparoscopic surgery (P = .01).

Percutaneous cryoablation cost $14,153.69 on average compared with $22,556.93 for the laparoscopic approach, a reduction of 59.5% that was statistically significant at the P = .0011 level, Dr. Hinshaw said.

During percutaneous cryoablation argon gas enters the tip of the probe and extracts heat from the surrounding cells, resulting in an "ice ball" that freezes and kills the tumour. The nonsurgical treatment spares the majority of the healthy kidney tissue and can be repeated as often as needed.

The radiologist uses imaging to pinpoint the tumour, and then inserts the cryoprobe through the skin, similar to the way a biopsy is performed. This can be performed under general anaesthesia, but is often possible with local anaesthesia and conscious sedation.

By using imaging the radiologist can avoid going through any adjacent structures or harming healthy tissue. If necessary, adjacent structures can be displaced prior to the ablation to minimise collateral damage. Laparoscopy, on the other hand, requires general anaesthesia, as well as multiple abdominal incisions to allow access for the surgical instruments. It is also associated with a longer recovery time.

The interventional treatment had no major complications as opposed to the surgical procedure, which resulted in complications in 6% of patients studied. The difference in complications rates, however, was not statistically significant, Dr. Hinshaw said in his poster presentation and at a press briefing March 2^nd.

"Unfortunately, not all patients are viable candidates for percutaneous ablation and we work closely with our urology colleagues to ensure that each patient receives the most appropriate treatment," Dr. Hinshaw said.

"We are excited about this study because it offers patients with renal cell carcinoma a less traumatic treatment that can be repeated as needed," Dr. Hinshaw added. "Depending on the stage of the disease, this procedure can be curative, but can also be used for palliative treatment in some settings."