Debra Ann Gervais MD, Presenter: Speakers Bureau, Covidien AG Research grant, Covidien AG

Raul Nirmal Uppot MD, Abstract Co-Author: Nothing to Disclose

Ronald Steven Arellano MD, Abstract Co-Author: Nothing to Disclose

Francis J. McGovern MD, Abstract Co-Author: Research grant, Covidien AG Speaker, Covidien AG

W. Scott McDougal MD, Abstract Co-Author: Nothing to Disclose

Peter Raff Mueller MD, Abstract Co-Author: Nothing to Disclose

To review outcomes following RFA of renal tumors in patients with solitary kidneys.

30 patients with solitary kidneys underwent RFA of 37 renal masses (mean 3.3 cm; range 1.1 – 7.1 cm) from 1998 to 2007. 2 patients had 3 tumors and 3 had 2 tumors treated with RFA. 34 tumors were treated with straight electrodes and 3 with multitined expandable electrodes. Medical records were reviewed retrospectively recording effectiveness of RFA, complications, changes in serum CR, and changes in eGFR that may have implications for imaging follow up. eGFR was categorized by National Kidney Foundation/ACR criteria as < 30, 30 – 60, or > 60 mL/min/1.73 m2.

Complete ablation was achieved in 35/37 tumors 95% with follow up ranging from 3 months to 8 years. 2 large tumors (6.5 & 7.1 cm) remained incompletely treated. In the absence of urinary obstruction, mean Cr before and after RFA was 1.48 to 1.56 mg/dL. Paired t-test showed a significant (p = 0.02) difference in serum Cr before and after RFA. eGFR as determined by the MDRD formula reflected Cr changes: Using the ACR recommendations for MR with gadolinium, 4 patients moved to the next worse category on the MDRD eGFR scale with 3 dropping from eGFR > 60 down to the 30-60 range, and 1 dropping from 30 to 60 down to < 30. Obstructive complications occurred in 4 patients: temporary secondary to hemorrhage in 3 patients and a ureteral stricture requiring permanent nephrostomy drainage in 1 patient. In these patients, Cr changes were more pronounced acutely up from 1 to 8 mg/dL but trended towards baseline as obstruction resolved.  

In patients without complications of urinary obstruction, ablation of renal tumors in solitary kidneys results in small changes in creatinine levels comparable to historical results following partial nephrectomy in solitary kidneys. In a small number of patients, decreases in eGFR may have implications for imaging follow up. Obstructive complications require prompt treatment, but most resolve.

Patients with solitary kidneys can be treated with RFA with small increases in Cr levels in most cases. Decreases in eGFR may have implications for imaging follow up in a small number of patients.

Gervais, D, Uppot, R, Arellano, R, McGovern, F, McDougal, W, Mueller, P, Radiofrequency Ablation of Renal Tumors in Patients with Solitary Kidneys: Effectiveness and Changes in Estimated Glomerular Filtration Rate.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6009948.html