Beyond the Abstract - Utility of the R.E.N.A.L. nephrometry scoring system in objectifying treatment decision-making of the enhancing renal mass, by Daniel Canter, Alexander Kutikov, and Robert G. Uzzo

BERKELEY, CA (UroToday.com) - The decision as to how to best treat a clinical stage I/II renal mass is often overly dependent on subjective variables such as physician experience and perception.

"Our scoring system attempts to provide the quantification to ultimately improve patient care and better inform our treatment decision-making process."

We developed the first objective measure of tumor mass complexity in an effort to bring standard objective metrics to the decision-making process of radical nephrectomy (RN) versus nephron-sparing surgery (NSS). It was envisioned that such a system would allow appropriate comparisons across different institutional series and better objectify risks and rewards preoperatively for patients facing difficult medical decisions.

The R.E.N.A.L.-Nephrometry scoring system objectifies the most important anatomic components of a given renal mass. In brief, the scoring system is modeled on the five most reproducible features of a solid renal mass: the (R)adius (tumor size), the (E)xophytic/endophytic properties of the tumor, the (N)earness at the deepest portion of the tumor to the collecting system or renal sinus, an (A)anterior (a)/posterior (p) location descriptor, and the (L)ocation of the mass relative to the polar line. Each individual component except for the (A) descriptor is scored on a 1-, 2-, or 3-point scale (available from http://www.nephrometry.com or http://www.cancernomograms.com).(1) The (A) describes the principal mass location relative to the coronal plane of the kidney; if the mass cannot be described as anterior or posterior, the suffix “x” is assigned. Additionally, the suffix “h” is used to designate a hilar location of a tumor if the tumor abuts the main renal artery or vein. Since the introduction of our objective scoring system, we have sought to characterize perioperative outcomes of renal masses undergoing surgical excision using the large institutional kidney cancer database at The Fox Chase Cancer Center stratified by a tumor’s Nephrometry score. To date, we have found that a tumor’s Nephrometry score can predict for malignant and/or high grade pathology.(2) Furthermore, we have also found that increasing tumor complexity as measured by Nephrometry is correlated with increasing rates of major urologic complications in patients undergoing nephron-sparing surgery (NSS).(3) As the first such system to objectify renal mass complexity and based on our previous work, Nephrometry has become widely adopted and reported by other investigators in over 40 publications since its introduction in 2009. Other scoring systems have been subsequently proposed, however they differ very little from the R.E.N.A.L.-Nephrometry scoring system and are more difficult to apply.

In our recent article “Utility of the R.E.N.A.L.-Nephrometry Scoring System in Objectifying Treatment Decision-Making of the Enhancing Renal Mass,” we identified 615 consecutive patients with an available Nephrometry score who underwent surgical excision of their enhancing renal mass. Of this cohort, 128 (20.8%), 281 (45.7%), and 206 (33.5%) patients had a low (Nephrometry score=4-6), moderate (NS=7-9), or high (NS=10-12) complexity renal mass, respectively.(4) 66% of all patients underwent NSS to treat their renal mass in our cohort. Conversely, 2/3 of all patients who underwent a radical nephrectomy (RN) had a high complexity renal mass.

In analyzing our data, we found that tumors with an increasing Nephrometry score as well as increasing component scores were more likely to undergo RN than NSS (p<0.0001).(4) For example, 81.1% of tumors treated with RN had a “R” component score of 3, indicating a tumor size > 7 cm whereas only 18.9% of NSS had a R=3 component score.(4) A similar trend was noted in determining the predictors for deciding between open versus minimally-invasive (MIS) NSS. Patients treated with open NSS has a mean NS=8.19 as opposed to those treated with MIS-NSS whose mean NS=6.62 (p<0.0001).(4) Also, an increasing component score of all scoring system components except for tumor location (a) and hilar location (h) were correlated with an open NSS technique.

With so many apparently equivalent treatment options available for the clinical T1 renal mass,(5) the R.E.N.A.L.-Nephrometry scoring system provides a tool to objectify a renal mass anatomy. Ultimately, the decision of “whether” and “how” to treat a given renal mass is complex and based on many factors, not the least of which are incentives—both the surgeons and the patients. If the mass can be quantitatively described as “not worrisome,” the incentives to treat can be mitigated since the risks of treatment would outweigh the benefits. Our scoring system attempts to provide the quantification to ultimately improve patient care and better inform our treatment decision-making process.

References:

  1. Kutikov A, Uzzo RG. The R.E.N.A.L. nephrometry score: a comprehensive standardized system for quantitating renal tumor size, location and depth. J Urol. 2009 Sep;182(3):844-53.
  2. Kutikov A, Smaldone MC, Egleston BL, Manley BJ, Canter DJ, Simhan J, et al. Anatomic features of enhancing renal masses predict malignant and high-grade pathology: a preoperative nomogram using the RENAL Nephrometry score. Eur Urol. 2011 Aug;60(2):241-8.
  3. Simhan J, Smaldone MC, Tsai KJ, Canter DJ, Li T, Kutikov A, et al. Objective measures of renal mass anatomic complexity predict rates of major complications following partial nephrectomy. Eur Urol. 2011 Oct;60(4):724-30.
  4. Canter D, Kutikov A, Manley B, Egleston B, Simhan J, Smaldone M, et al. Utility of the R.E.N.A.L. nephrometry scoring system in objectifying treatment decision-making of the enhancing renal mass. Urology. 2011 Nov;78(5):1089-94.
  5. Campbell SC, Novick AC, Belldegrun A, Blute ML, Chow GK, Derweesh IH, et al. Guideline for management of the clinical T1 renal mass. J Urol. 2009 Oct;182(4):1271-9.

 

 

Written by:
Daniel Canter, Alexander Kutikov, and Robert G. Uzzo as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

Utility of the R.E.N.A.L. nephrometry scoring system in objectifying treatment decision-making of the enhancing renal mass - Abstract

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