Clinical success achieved in 97.5% of cases, with minimal complications.


WASHINGTON, D.C.—Cryoablation is an appropriate option for patients with unresectable renal masses, but long-term follow-up studies are needed before this modality can be expanded to treatment of all potential surgical candidates, researchers say.

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“Right now, the data that we have is that this is an excellent management [option] for patients who are not surgical candidates,” said lead investigator Nael Saad, MD, an instructor of interventional radiology at Washington University School of Medicine in St. Louis, Mo. “We need to know if these procedures are effective in the long run and whether there will be local progression.”


He and his colleagues examined the technical and clinical outcomes of percutaneous cryoablation of unresectable renal tumors. Forty patients (32 men, eight women, mean age,

68.5 years) with unresectable suspicious renal masses were treated from March 2005 to August 2007.


Dr. Saad, who presented the study findings here at the Society of Interventional Radiology’s 33rd Annual Scientific Meeting, said all the procedures were performed with moderate sedation under CT-fluoroscopic guidance and monitoring.


The clinicians used two different cryoablation systems: Endocare (Irvine, Calif.) and Galil Medical (Yokneam, Israel). Two freeze/thaw cycles (10 and 5 minutes, respectively) were performed for each lesion. The researchers conducted follow-up imaging (CT or MRI) at one, four to six, and 12 months after the procedure and then annually.


Of 42 lesions treated, half were in the right kidney. Half of the lesions were in the lower, 23.5% were in the upper pole, and 26.5% were inter-polar. In addition, 82% of the lesions were exophytic, 3% were central, and 15% were both. Approximately 91% of the lesions were posterior and 88% were solid in consistency. 


The mean number of cryoprobes used was 2.7 per lesion (range, one to six). The disease-free survival rate was 97.5% (39 out of 40 patients). Two patients had residual tumors after initial ablation, but these were successfully treated at a second visit. The mean follow-up was 7.1 months (a range of 0-25.2 months). To date, none of the patients has experienced local progression, Dr. Saad said.