Laparoscopic radiofrequency for small renal masses. What is the best imaging technique?

The diagnosis of low clinical stage renal cancer has risen up during the last years thanks to the advances on radiological imaging tools. As a result, several minimally invasive techniques have appeared which offer the same oncological results than conventional/laparoscopic surgery without their morbidity. One of these techniques is percutaneous radiofrequency (RF). In this paper we expose the oncological and functional outcomes of percutaneous RF after a review of the literature. We made a search using the principal medical libraries as the Cochrane Central of clinical controlled trials, Medline and the Excerpta Medica database.We used the following terms: "renal radiofrequency ablation US guided", "renal radiofrequency ablation CT guided ", "renal radiofrequency ablation MR guided"," renal radiofrequency ablation "," renal radiofrequency ablation image guided". A methodological and clinical expert analyzed each abstract.All studies where renal cancer or small renal masses were treated were included. We excluded series with hereditary renal cancer only or metastatic cancer, technical series and those where tumor recurrence or other oncological criteria were not evaluated. Data collection included patient age, tumor size, follow up and oncological data. The oncological data evaluated included: tumor local recurrence (radiological or pathologic evidence of residual disease after initial treatment, independently of time to recurrence, accordingly to the recommendations of the Working group on image guided tumor ablation) or distant metastases. There were a total of 1621 papers. Only 24 met the inclusion criteria, and we only found 1 controlled trial, and several retrospective studies and series of cases. A total of 11, 10 y 3 for US, CT and MR guided RF, respectively, with a follow up of 1-57 months, with a total of 1764 tumors in 1524 patients. Tumor size was 1 to 8.9cm and local recurrence between 0%-5.06%. Surgical treatment remains the "gold standard" for clinical stage I renal cancer because we do not have enough long term scientific information to be sure that percutaneous renal RF offers the same oncological results than surgery, but percutaneous renal RF is an option for those patients that are not candidates to surgery.