Partial nephrectomy, laparoscopic or open, remains the standard of care for small renal tumours in many countries. There is an increasing realisation that operative management may incur unnecessary morbidity for often indolent tumours and minimally invasive ablative procedures such as percutaneous cryoablation (pCRA) techniques are increasingly being used. The ‘R.E.N.A.L’ nephrometry scoring system1 attempts to quantify and stratify tumour complexity based on reproducible anatomic features to aid surgical decision making. This score has been shown to predict intra-operative warm ischaemic time and complications2,3. This study...

A retrospective review of histologically (via biopsy) - proven renal cell carcinomas treated with pCRA at our institution between May 2007 and November 2011 was performed. The pre-ablation R.E.N.A.L nephrometry score was derived for each patient and correlated with treatment outcomes and complication rates. The R.E.N.A.L score is calculated using: maximum tumour radius (R), exophytic or endophytic (E), as shown in images 1, nearness to renal collecting system (N), as shown in image 2, anterior or posterior location (A) and location of tumour relative to...

In total 61 tumours were treated with a mean size of 32mm (range 15-62mm). Mean follow-up was 16-months (range 3-42months). The mean R.E.N.A.L score was 7 (range 4-10), 20 low, 36 medium and 5 high complexity. 55/61 patients (90.2%) were successfully treated following single-session cryoablation, 6 patients showed residual disease on follow-up imaging . In terms of treatment success, no significant association with the R.E.N.A.L nephrometry score (P=0.211) was found. 5/61 patients (8.2%) developed a significant complication again with no significant association with the R.E.N.A.L...

Despite its continued use with surgical planning, in our study the R.E.N.A.L nephrometry score appears to have no significant correlation with procedural outcome or complication rate following pCRA. At our institution we will not be using the R.E.N.A.L score for ablation therapies and we will continue to analyse each tumour on an individual basis at our Urology multi-disciplinary team (MDT) meeting.

(1) Kutikov, A. et al. The R.E.N.A.L nephrometry score: a comprehensive standardised system for quantitating renal tumour size, location and depth. J Urol. 2009 Sep;182(3):844-53 (2) Lavallee, M.D. et al. The association between renal tumour scoring system and ischemic time during open partial nephrectomy. Can. Urol. Assoc. J. 2012 (3) Mayer, W.A, et al. Higher RENAL Nephrometry Score is predictive of longer warm ischemia time and collecting system entry during laparoscopic and robotic-assisted partial nephrectomy. Urology. 2012 May;79(5):1052-6