Comprehensive assessment of renal tumor complexity in a large percutaneous cryoablation cohort

To evaluate the association between renal tumor complexity and outcomes in a large cohort of patients undergoing percutaneous cryoablation (PCA).

Patients with renal tumors treated with PCA were identified using our prospectively-maintained ablation registry (2003-2015). Salvage procedures and inherited tumor syndromes were excluded. The associations between R.E.N.A.L. Nephrometry Score (NS) and risk of complications, renal function impairment, local failure, and cancer-specific mortality (CSM) were evaluated using univariate and multivariable logistic, linear and Cox regression models.

The cohort included 618 tumors treated during 580 procedures in 565 patients. Median follow-up was 34 months (IQR 14,66). Complications (any grade) during a procedure (n[total]=87, 15%) were more frequent with higher NS (Score 4-6: 10%; 7-9: 14%; 10-12: 36%;p<0.001). Higher NS was independently associated with risk of complications (OR[per 1 point]=1.3;95%CI 1.2-1.5;p<0.001). Of all the NS components, tumor size was the most strongly associated with complication risk (OR=3.4;95%CI 2.2-5.2;p<0.001). Median decline in GFR from baseline was 9% (IQR 0,22) at last follow-up. Each additional point in NS was associated with a 1.3% (95%CI 0.4-2.1;p=0.005) greater GFR decline from baseline. Nephrometry score was not significantly associated with local failure (n[total]=14, 2%; Score 4-6: 2%; 7-9: 3%; 10-12: 5%; p=0.32) or CSM (n[total]=8, 2%; Score 4-6: 2%; 7-9: 3%; 10-12: 2%; p=0.88).

PCA for high-complexity tumors is associated with a tumor size-driven increased risk of post-procedural complications. Higher NS is associated with a small, clinically minor additional decline in renal function. Risks for local failure and CSM are low, regardless of tumor complexity. This article is protected by copyright. All rights reserved.

BJU international. 2017 Mar 13 [Epub ahead of print]

Bimal Bhindi, R Houston Thompson, Ross J Mason, Mustafa M Haddad, Jennifer R Geske, A Nicholas Kurup, James D Hannon, Stephen A Boorjian, Bradley C Leibovich, Thomas D Atwell, Grant D Schmit

Department of Urology, Mayo Clinic, Rochester, MN, USA., Department of Radiology, Mayo Clinic, Rochester, MN, USA., Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA., Department of Anesthesia, Mayo Clinic, Rochester, MN, USA.