Comparison of Percutaneous Renal Mass Biopsy and R.E.N.A.L. Nephrometry Score Nomograms for Determining Benign Versus Malignant Disease and Low- Versus High-Risk Renal Tumors

To compare the accuracies of renal mass biopsy (RMB) and R.E.N.A.L. nephrometry score (RNS) nomograms for predicting benign versus malignant disease, and low- versus high-risk renal tumors.

We included 281 renal masses in 277 patients who had complete RNS, preoperative RMB, and final pathology from renal surgery for clinically localized renal tumors. RMB and final pathology were determined to be benign or malignant, and malignancies were classified as low- (Fuhrman grade I/II) or high- (Fuhrman grade III/IV) risk (benign included in low-risk group). Previously published RNS-nomograms were used to determine probabilities of any cancer and high-risk cancer. The gamma statistic was used to assess strength of association between RMB or RNS with final pathology.

Of the 281 masses, 13 (5%) and 268 (95%) were confirmed benign and malignant, respectively, and 155 (55%) and 126 (45%) were confirmed low- and high-risk, respectively, on final pathology. The area under the curve (AUC) of the RNS-nomograms for benign versus malignant disease and for low- versus high-risk renal tumors were 0.56 and 0.64, respectively. Concordances for predicting benign versus malignant disease was 99% for RMB (p<0.01, gamma 0.99) and 29% for RNS-nomogram (p=0.16, gamma 0.38). Concordances for predicting low- versus high-risk renal tumors were 67% for RMB (p<0.01, gamma 0.97) and 61% for RNS-nomogram (p<0.01, gamma 0.47), respectively.

Although RNS-nomograms are useful for discriminating between benign versus malignant renal masses, and low- versus high-risk renal tumors, they are outperformed by RMB.

Urology. 2016 Jun 01 [Epub ahead of print]

Takahiro Osawa, Khaled S Hafez, David C Miller, Jeffrey S Montgomery, Todd M Morgan, Ganesh S Palapattu, Alon Z Weizer, Elaine M Caoili, James H Ellis, Lakshmi P Kunju, J Stuart Wolf

Department of Urology, University of Michigan Health System, Ann Arbor, Michigan. Electronic address: ., Department of Urology, University of Michigan Health System, Ann Arbor, Michigan., Department of Urology, University of Michigan Health System, Ann Arbor, Michigan., Department of Urology, University of Michigan Health System, Ann Arbor, Michigan., Department of Urology, University of Michigan Health System, Ann Arbor, Michigan., Department of Urology, University of Michigan Health System, Ann Arbor, Michigan., Department of Urology, University of Michigan Health System, Ann Arbor, Michigan., Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan., Department of Urology, University of Michigan Health System, Ann Arbor, Michigan; Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan., Department of Pathology, University of Michigan Health System, Ann Arbor, Michigan., Department of Urology, University of Michigan Health System, Ann Arbor, Michigan.