Renal Function Outcomes in Patients Treated for Renal Masses Smaller Than 4 cm by Ablative and Extirpative Techniques

Purpose: We examined the effect of radical nephrectomy, partial nephrectomy and radio frequency ablation on renal function in patients with stage T1a renal masses. Materials and Methods: A total of 242 consecutive patients from July 1995 to March 2005 undergoing primary treatment for unilateral renal masses smaller than 4 cm and a normal contralateral kidney were identified. Renal function was calculated using the modified Modification of Diet in Renal Disease equation. The rate of decrease in the glomerular filtration rate below 60 ml per minute 1.73 m ² was compared among the 3 treatment modalities. Results: A total of 86, 85 and 71 patients were treated with radio frequency ablation, partial nephrectomy and radical nephrectomy, respectively. Preoperatively stage 3 chronic kidney disease (glomerular filtration rate less than 60 ml per minute per 1.73 m ²) was identified in 65 patients (26.7%), including 26.7%, 27.1% and 26.8% who underwent radio frequency ablation, partial nephrectomy and radical nephrectomy, respectively. Following intervention the 3-year freedom from a glomerular filtration rate decrease of below 60 ml per minute per 1.73 m ² for radio frequency ablation, partial nephrectomy and radical nephrectomy was 95.2%, 70.7% and 39.9%, respectively (p <0.001). Multivariate analysis showed that radical nephrectomy was an independent risk factor vs radio frequency ablation and partial nephrectomy for stage 3 chronic kidney disease (HR 34.3, 95% CI 4.28-275 and 10.9, 95% CI 1.36-88.7, respectively). Conclusions: Decreased renal function is prevalent in patients with small unilateral renal tumors even with a normal contralateral kidney. Ablative or extirpative nephron sparing techniques are effective for preserving renal function in these patients.