Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 32  |  Issue : 2  |  Page : 75-79

Nephrometry scoring system selects candidates for radical nephrectomy versus nephron-sparing surgery for treatment of renal masses and predicts surgical and oncological outcome


1 Department of Urology, Armed Forces College of Medicine, Cairo, Egypt
2 Department of Maadi Military Hospital, Egyptian Military Medical Academy and Urology Specialist at Maadi Armed Forces Hospital, Cairo, Egypt

Date of Submission27-Nov-2019
Date of Decision09-Dec-2019
Date of Acceptance27-Jan-2020
Date of Web Publication28-Nov-2020

Correspondence Address:
Ahmed Mohamed Saafan
Armed Forces College of Medicine, Cairo
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/HUAJ.HUAJ_6_20

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  Abstract 


Purpose: The study was designed to ensure the sensitivity of preoperative planning by applying radius, endophytic/exophytic, nearness to collecting system, anterior/posterior, and location to poles (RENAL) nephrometry scoring system on computed tomography films of patients having organ-confined solid and cystic renal tumors and to assess its correlation with the surgical technique by applying RENAL on the specimen intraoperative. Materials and Methods: Eighty-five patients with organ-confined solid and cystic renal masses underwent RENAL nephrometry system which was correlated with the surgical technique either radical or nephron-sparing surgery or the surgical and oncological outcome. Results: RENAL nephrometry scoring system shows high sensitivity with the type and outcome of surgery of resection of the renal tumors. Conclusion: RENAL nephrometry score system is an objective method to help in the decision of surgical approach to resect organ-confined solid and cystic renal tumors.

Keywords: Radius, endophytic/exophytic, nearness to collecting system, anterior/posterior, and location to poles system, nephron sparing, radical


How to cite this article:
Saafan AM, Abdelmonem Mohamed HA, Mansour MF, Ahmed Tolba MK. Nephrometry scoring system selects candidates for radical nephrectomy versus nephron-sparing surgery for treatment of renal masses and predicts surgical and oncological outcome. Hellenic Urology 2020;32:75-9

How to cite this URL:
Saafan AM, Abdelmonem Mohamed HA, Mansour MF, Ahmed Tolba MK. Nephrometry scoring system selects candidates for radical nephrectomy versus nephron-sparing surgery for treatment of renal masses and predicts surgical and oncological outcome. Hellenic Urology [serial online] 2020 [cited 2021 Jan 28];32:75-9. Available from: http://www.hellenicurologyjournal.com/text.asp?2020/32/2/75/301823




  Introduction Top


Prevalence of renal masses increased due to advances of imaging modalities, so the classic triad of pain, hematuria, and palpable renal mass is not present except in advanced cases.[1]

There are multiple options for managing renal masses, particularly for those with small renal mass. Surgery is the gold standard for the treatment of localized renal cell carcinoma (RCC).[2],[3],[4],[5],[6]

Nephron-sparing surgery has become an established treatment for renal tumors, particularly when the preservation of renal parenchyma is critical as in single functioning kidney and bilateral synchronous pathology.[2],[3]

Treatment of renal tumors depends on description of tumor anatomy and the experience of the surgeon. Hence, Alexander Kutikov and Uzzo have described the radius, endophytic/exophytic, nearness to collecting system, anterior/posterior, and location to poles (RENAL) nephrometry score in 2009.[7]

RENAL nephrometry score which was one of the first systems created to provide a standardized descriptive system for renal masses based on radiologic findings.

Target of these nephrometry scoring systems was to make comparative studies between operative results and give standard anatomical data of the tumor.[7],[8],[9]

This system could be reliable as it describes the tumor anatomical features as radius, exophytic/endophytic, nearness of the tumor the collecting system, location of the tumor to renal poles, and being anterior or posterior.[7]

Application of RENAL nephrometry scoring preoperatively may be used as a guide to the complexity and choice of surgery for solid and cystic renal masses and patient counseling, with reference to postoperative outcomes. Widespread use of this score may act as communication tools among specialists.[10],[11],[12],[13]


  Materials and Methods Top


Studying data of 85 patients who are fit for anesthesia and having resectable nonmetastatic solid and cystic renal tumors was done during the period of January 2018–April 2019.

Routine preoperative assessment of the patients included computed tomography (CT) scan with intravenous contrast.

RENAL system was applied on mass lesions in CT preoperatively and on the excised specimens postoperatively as follows:

Radius: one point is given to tumors that are ≤4 cm, two points are given to those that more than 4 cm not exceeding 7 cm, and those that measure 7 cm and more are given 3 points.

The relationship between the renal tumor and the surface of the renal cortex is described by exophytic/endophytic component.

Not all renal tumors are spherical, so the safest way to calculate this score is by imagination of where the renal cortex would normally be if the mass is not present as renal tumors distort the normal contour of the kidney.

The distance between tumor's outermost point and renal cortex <1> and the distance between tumor's most endophytic point and renal cortex <2> are measured.

If <1> is greater than <2>, so the tumor is exophytic and vice versa.

One point is given for masses that are 50% exophytic or more. Two points are given for those that are <50% exophytic. Three points are given for the totally submitted in the renal parenchyma.

The nearness of tumor's innermost point and the closest fat sinus or collecting system is checked in secretory phase CT.

Tumors 7 mm or more from the collecting system or renal fat sinus are given one point. Two points are given to those that are >4 mm but <7 mm away. Three points are given for <4 mm from the nearest collecting system or fat sinus.

The anterior tumors are assigned “a,” while the posterior ones are assigned “p.” Using axial CT aims to detect whether the renal tumor is anterior or posterior by drawing an imaginary line parallel to the direction of the renal hilar structures equally dividing the renal parenchyma into anterior and posterior planes.

The location component describes the relation of the tumor to the renal polar line which is an imaginary plane where the medial renal parenchyma first intersected with the renal sinus fat, collecting system, or vessels, especially in coronal CT.

One point is given for tumors that are completely above or below the polar lines.

Two points are given for those that are crossing <50%.

Three points are given for those that are completely between polar lines or cross-polar lines >50% of the tumor's radius.

When the tumor is hilar, “h” is added to the score giving it more complexity.

RENAL system is subdivided according to the complexity into low,[4],[5],[6] moderate,[7],[8],[9] and high.[10],[11],[12]


  Results Top


Eighty-five patients were included in this study and subdivided according to the type of surgery into radical cases and nephron-sparing cases.

The mean age among radical nephrectomy cases was 57.9 ± 13.4 years, while the mean body mass index (BMI) was 24.4 ± 1.6, with males representing 57.4% of cases [Figure 1].
Figure 1: Post operative blood loss v/s pre nephrometry score

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The mean operative time was 4.52 h, average blood loss: 362.30 cc, blood loss in the drain: 252.46 cc, and application of the score on specimens with a mean score 10.43; three patients were complicated with not free safety margins and needed intervention.

Change in hemoglobin, creatinine, and nephrometry score after operation among radical cases

Forty-six cases showed no change in score comparing the application of the study on CT and specimens, while 15 showed up the score.

Personal data among (nephron-sparing surgery) cases

The mean age among (nephron-sparing surgery [NSS]) cases was 57.5 ± 10.8 years, while the mean BMI was 24.6 ± 1.8, with males representing 62.5% of the cases.

The mean operative time was 5.29 h, average blood loss was 506.25 cc, average blood loss in drain was 458.33 cc, and mean score was 6.96; four cases were complicated with not free safety margins and eight with urine leak from which three required intervention. No recurrences were detected.

Twenty-seven patients (31.7%) of the total 85 patients with moderate complexity nephrometry score were studied as follows:

Only one case (1.1%) of score 7 who underwent NSS was complicated with transient creatinine rise, 4 cases (4.7%) of score 8 were complicated with bleeding and the safety margins were not free from malignant cells, and 7 cases (8.4%) of score 9 were complicated with bleeding and the safety margins were not free from malignant cells [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6].
Table 1: Intra- and postoperative data among radical cases

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Table 2: Intra- and postoperative data among nephron-sparing surgery cases

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Table 3: Comparison between the two study groups in preoperative data

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Table 4: Comparison between the two groups in intra and postoperative data

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Table 5: Comparison between the two groups in change in hemoglobin, creatinine, and nephrometry score postoperatively

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Table 6: Relationship between the nephrometry score and the complications

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  Discussion Top


In Kutikov and Uzzo study in 2009, 50 patients with solid renal tumors were subdivided into low and moderate, by which these two groups were treated with minimally invasive NSSs.

High complexity masses were treated with open partial or laparoscopic radical nephrectomy.[7]

In our study, all patients of low score underwent NSS, 48.25% of moderate score underwent NSS, while 51.72% of moderate score and all patients of high score underwent radical nephrectomy.

Patients' number in Kutikov's study was 50 patients, while in ours, it was 85, 80 of them underwent open surgery and five treated laparoscopically, while in Kutikov's study, 31 underwent laparoscopy (14 radical and 17 NSS) and 19 had open surgery (5 radical and 14 NSS).

Naya et al. studied 142 patients and found that the mean RENAL nephrometry score in the radical group was higher than that in the NSS (9 vs. 7; with P < 0.0001), which our study agrees with some studies.[14]

In 2013, Oh et al. studied that 206 patients underwent different approaches of surgeries.

Fifty-three underwent open radical nephrectomy, 83 laparoscopic radical nephrectomy, 31 open NSS, and 39 laparoscopic NSS.

The mean score in radical nephrectomy group was score 8.89 and for the NSS group, it was score 6.09), with P < 0.0001.[12]

In 2014, Cost et al. studied 65 patients, they classified renal masses into low, moderate, and high complexity groups, the same as in our study, two out of five of low score underwent radical nephrectomy, in contrast to our low score group who all underwent NSS, while three out of 48 patients in the high complexity group of Cost et al. underwent NSS, in contrast to our high complexity group who all underwent radical nephrectomy.[13]

Explanations for this are the difference between sample size and demographic characteristics and the different pathologies of the resected renal tumors, as 86.5% of the renal tumors in our study were RCC against only 16.4% in Cost's study.


  Conclusion Top


RENAL scoring system is a good tool for making a decision for treating renal masses as follows:

Mild complexity group is better treated with NSS, score 7 moderate complexity renal tumors are more likely to be treated with NSS, while scores 8 and 9 are better treated with radical surgery, and high complexity group is better treated with radical surgery.

The RENAL nephrometry scoring system provides an easy methodology to stratify the complexity of renal tumors, aiding in treatment decision-making and counseling as well as providing a platform for standardized academic reporting. Although the data are preliminary, the nephrometry score appears to correlate with long-term outcomes. Renal abnormalities that might contribute to surgical morbidity, such as fusion or duplication, are not included in the scoring system, and as nephrometry becomes more widely adopted, modifications might become necessary. The interpreting radiologists will find that assigning a nephrometry score is simple and doing so will ensure that the salient features of a renal carcinoma are reported for operative planning.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Chen DY, Uzzo RG. Optimal management of localized renal cell carcinoma: Surgery, ablation, or active surveillance. J Natl Compr Canc Netw 2009;7:635-42.  Back to cited text no. 1
    
2.
Delakas D, Karyotis I, Daskalopoulos G, Terhorst B, Lymberopoulos S, Cranidis A. Nephron-sparing surgery for localized renal cell carcinoma with a normal contralateral kidney: A European three-center experience. Urology 2002;60:998-1002.  Back to cited text no. 2
    
3.
Sivarajan G, Huang WC. Current practice patterns in the surgical management of renal cancer in the United States. Urol Clin North Am 2012;39:149-60, v.  Back to cited text no. 3
    
4.
Georgiades C, Rodriguez R. Renal tumor ablation. Tech Vasc Interv Radiol 2013;16:230-8.  Back to cited text no. 4
    
5.
Gervais DA. Cryoablation versus radiofrequency ablation for renal tumor ablation: Time to reassess? J Vasc Interv Radiol 2013;24:1135-8.  Back to cited text no. 5
    
6.
Saksena M, Gervais D. Percutaneous renal tumor ablation. Abdom Imaging 2009;34:582-7.  Back to cited text no. 6
    
7.
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;182:844-53.  Back to cited text no. 7
    
8.
Ficarra V, Novara G, Secco S, Macchi V, Porzionato A, De Caro R, et al. Preoperative aspects and dimensions used for an anatomical (PADUA) classification of renal tumours in patients who are candidate for nephron-sparing surgery. Euro Urol 2009;56:786-93.  Back to cited text no. 8
    
9.
Simmons MN, Ching CB, Samplaski MK, Park CH, Gill IS. Kidney tumor location measurement using the C index method. J Urol 2010;183:1708-13.  Back to cited text no. 9
    
10.
Zhang GM, Zhu Y, Gan HL, Wang HK, Shi GH, Zhang HL, et al. Use of RENAL nephrometry scores for predicting tumor upgrading between core biopsies and surgical specimens: A prospective ex vivo study. Medicine (Baltimore) 2015;94:e581.  Back to cited text no. 10
    
11.
Reddy UD, Pillai R, Parker RA, Weston J, Burgess NA, Ho ET, et al. Prediction of complications after partial nephrectomy by RENAL nephrometry score. Ann R Coll Surg Engl 2014;96:475-9.  Back to cited text no. 11
    
12.
Oh JH, Rhew HY, Kim TS. Factors influencing the operative approach to renal tumors: Analyses according to RENAL nephrometry scores. Korean J Urol 2014;55:97-101.  Back to cited text no. 12
    
13.
Cost NG, DeFoor WR Jr., Crotty EJ, Geller JI. The initial experience with RENAL Nephrometry in children, adolescents, and young adults with renal tumors. Pediatr Blood Cancer 2014;61:1434-9.  Back to cited text no. 13
    
14.
Naya Y, Kawauchi A, Oishi M, Ueda T, Fujihara A, Naito Y, et al. Comparison of diameter-axial-polar nephrometry and RENAL nephrometry score for treatment decision-making in patients with small renal mass. Int J Clin Oncol 2015;20:358-61.  Back to cited text no. 14
    


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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