A study presented at the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) 2011, Munich, Germany, shows that percutaneous cryoablation may be an alternative therapy in patients with renal tumours who are poor candidates for surgery.
Lead investigator Xavier Buy, Non-Vascular Interventional Radiology, and his co-authors treated 83 non-surgical patients (mean age 72) between May 2007 and December 2010 with percutaneous cryoablation under CT or MR guidance with biopsy performed during the same session.
According to Buy et al, the aim of a single-session treatment was curative in tumours less than 4cm. In this study, the mean tumour size was 29mm (with a range of 8–70mm). Additionally, 65% tumours were central or mixed and 45% were anterior in close contact with the bowel.
Aside from three patients who required an additional session for complete ablation, all patients were treated in a single session with no evidence of tumour on follow-up (minimum follow-up, with MRI and creatinine, was four months). However, there were six perirenal haematomas (with one resulting in surgery) and one case of fatal Mendelson syndrome (which was probably due to sedation rather than cryoablation itself, the authors say).
Comparing cryoablation to radiofrequency ablation, Buy et al concluded that the major benefits of the former were: “The optimal visualisation of the iceball with CT and MR guidance, the better protection of the collecting system for central tumours and the ability to activate simultaneously multiple cryoprobes when treating large tumours. “They added that, in general, large and central tumours are associated with a higher risk of complications but this risk is “dramatically reduced” with cryoablation compared to radiofrequency ablation.
Speaking to Interventional News, Buy said: “Today, the gold standard treatment for small renal tumours is still partial nephrectomy. Cryoablation shows very promising preliminary results, particularly when considering that we only treated the weakest patients (poor surgical candidates). However, we need longer follow-up and larger series as the assessment of complete ablation is only based on imaging. On the other hand, histopathology after surgery gives a valuable analysis of resection margins.” He added that a randomised trial that compared partial nephrectomy to percutaneous cryoablation was needed, but explained that such a trial would be complex: “The success rate is very high with both techniques; so, we need large cohorts and very long follow-up to see if there is any difference in terms of oncologic efficacy.”