ROCHESTER, Minn. -- A review of 62 Mayo Clinic patients who underwent cryoablation to treat cancerous kidney tumors shows that the patients are cancer free for up to two and a half years after having had the procedure.

Also called cryotherapy or cryosurgery, cryoablation is a procedure in which extreme cold is applied to the tumor using a cryoprobe, a hollow needle-like device filled with argon gas. The gas rapidly freezes the targeted tumor.

As this study and others continue to show, cryoablation appears to be an effective treatment for cancerous kidney tumors. But researchers caution that at this time, it be used only for patients who are not candidates for surgery, because follow-up studies are needed before the procedure can be widely applied, states Thomas Atwell, M.D., a Mayo Clinic radiologist and the study's primary investigator.

Dr. Atwell will present these findings on Sunday, Nov. 25 at the annual meeting of the Radiological Society of North America in Chicago.

“This procedure appears to be a good option for some patients,” he says. The general criteria for cryoablation includes the size and appearance of the tumor and the number of lesions in the kidney.

In this study, 89 of 91 tumors were effectively treated in a single treatment session. Patients had tumors that ranged in size from 1.5 centimeters (cm) to 7.3 cm. The average size was 3.4 cm. Follow-up evaluations ranging from three months to two and a half years were available for 62 patients -- all whom remain cancer free at last report.

The standard treatment for kidney tumors is surgery, which is highly effective. For patients who undergo surgery, the hospital stay and recovery period are longer as compared to patients treated with cryoablation. Patients who undergo cryoablation will have small ¼ inch incision where the cryoprobe is inserted. The mark is covered with a bandage and recovery usually amounts to one day in hospital, as compared to several days for patients who undergo surgery.