R.E.N.A.L. Nephrometry Score Predicts Early Tumor Recurrence and Complications after Percutaneous Ablative Therapies for Renal Cell Carcinoma: A 5-Year Experience

The R.E.N.A.L. (radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior, and location relative to polar lines) nephrometry score analyzes anatomical variables and has been shown to correlate with outcomes and complications in the surgical treatment of RCC, but has remained controversial when applied to ablation. This was a retrospective study of 87 consecutive patients who underwent RF or cryoablation of 101 RCC lesions staged 1A (organ confined, <4cm), aimed at evaluating the usefulness of the R.E.N.A.L. scoring system in ablative therapy. All patients underwent CECT immediately after the procedure to document technical success, and follow up (mean 34.6 months) was performed on either CT or MR. The median R.E.N.A.L. score was 7 in the cryoablation (range 4-10) cohort and 5 in the RF cohort, with higher risk lesions generally being treated more often with cryoablation. Technical success was 100%, with overall recurrence of 16.84%, and complication rate of 9.9%. R.E.N.A.L. scores of >8 correlated with increased early (1st year) recurrence (p=0.001), overall recurrence (p=0.0001), and associated periprocedural complications (p=0.001) despite treatment method. The R.E.N.A.L. nephrometry score has been validated in the urological literature in surgical treatment of RCC (including partial nephrectomy and laparoscopic cryoablation) and the authors argue that this study validates this scoring system when applied to percutaneous ablation of RCC as it included patients with RCC exclusively.

Comment:

Although retrospective in design, and relatively small in numbers, the study was well designed and the statistical analyses were appropriate. While the study identified a higher incidence of recurrence and complications in the cryoablation group, these patients had higher risk lesions. The authors found that R.E.N.A.L. scores >8 were correlated with increased overall and early recurrence as well as increased complication rates independent of the technique used. This study validates the use of the R.E.N.A.L score in the setting of percutaneous ablative therapies and its use as a screening tool for patient selection and prediction of complications.


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Early recurrence after ablation procedure. (a) A 63-year-old man presented initially for ablation of an anterior lower 1.5-cm lesion (R.E.N.A.L. score 8a) (arrow). (b) Technical success was determined immediately after ablation (arrow). (c) The patient presented 12 months after the procedure with a predominantly exophytic lesion (R.E.N.A.L. score 6x) within the lower pole of the right kidney. Additional cryoablation was performed with a successful outcome (arrow).


Citation:  Camacho, J. C. et al. R.E.N.A.L. (Radius, Exophytic/Endophytic, Nearness to Collecting System or Sinus, Anterior/Posterior, and Location Relative to Polar Lines) Nephrometry Score Predicts Early Tumor Recurrence and Complications after Percutaneous Ablative Therapies for Renal Cell Carcinoma: A 5-Year Experience. Journal of Vascular and Interventional Radiology 26, 686–693 (2015).


Post author: Andre Uflacker MD,   Fellow in Vascular and Interventional Radiology, University of Virginia