Cryoablation versus minimally invasive partial nephrectomy for small renal masses in the solitary kidney: impact of approach on functional outcomes.

PURPOSE We evaluated the change in renal function after renal cryoablation and partial nephrectomy based on tumor complexity according to the R.E.N.A.L. nephrometry score. MATERIALS AND METHODS We retrospectively reviewed the data of patients who had a renal tumor in a solitary kidney, and underwent renal cryoablation and partial nephrectomy between December 2000 and January 2012. Renal tumor complexity was categorized into 3 groups by R.E.N.A.L. nephrometry score as low (4 to 6), intermediate (7 to 9) and high (10 to 12). All baseline demographic data, perioperative parameters and followup data including renal function were collected. Comparisons were made among similar tumor complexities. RESULTS In the renal cryoablation and partial nephrectomy groups 29 patients (43 tumors) and 33 patients were identified, respectively. In all renal tumor complexities, renal cryoablation provided a better perioperative outcome in terms of median operative time, estimated blood loss, transfusion, hospital stay and complications. The median change in serum creatinine and estimated glomerular filtration rate was slightly greater in the partial nephrectomy group. However, the differences were not statistically significant for any of the tumor complexities. Three patients (10%) in the renal cryoablation group and 2 (6%) in the partial nephrectomy group required long-term dialysis. CONCLUSIONS In patients with solitary kidneys, renal cryoablation is associated with superior perioperative outcomes compared to partial nephrectomy. Specifically, partial nephrectomy is not associated with greater loss of renal function than renal cryoablation regardless of the extent of tumor complexity.