Editorial Comment

Editorial Comment from Dr Mitsui to Association of RENALnephrometry score with outcomes of minimally invasivepartial nephrectomy

Recently, the anatomical features of kidney tumors havebeen investigated with more comprehensive methods todetermine objective and reproducible characteristics thatindicate the resectability of individual renal masses. TheRENAL nephrometry score (RNS) is a major nephrometryscoring system that uses five different anatomical character-istics of radiographic features.1 Some researchers havesuggested that RNS is a good preoperative predictor ofperioperative complications and surgical outcomes inpatients undergoing a partial nephrectomy (PN).2–4 Thepresent study by Ellison et al. is interesting in regard tothe finding that RNS was useful as a predictive tool forperioperative outcomes and complications of PN in a rela-tively large sample size, though such prediction remainschallenging.5

First, the authors showed that the distance from the tumorto the renal sinus, known as the “N” portion of the RNS,might be the strongest predictor of perioperative outcome.The recent trend of surgical procedures is to use a methodwith minimally invasive potential, such as laparoscopic orrobotic assisted laparoscopic PN procedures, as opposed toan open approach, even for cases with highly complextumors. However, the optimum therapeutic strategy for suchtumors remains controversial. The results of this retrospec-tive study indicate that cases with a higher proportion of the“N” portion have worse perioperative outcomes, which waseven shown in cases in the same RNS group. Thus, there isa possibility that the “N” portion of the RNS will provideuseful information for determining a more reasonabletherapeutic strategy for patients with highly complex renaltumors.

Second, RNS was significantly correlated with histologi-cal findings of renal masses, as previously shown in otherstudies.6,7 Recent advances in imaging technology have ledto earlier detection of asymptomatic and organ-confinedrenal masses of smaller size. However, these small renalmasses pose a diagnostic and management dilemma. In thenear future, the RNS might become a useful tool for guidingmanagement of these small renal masses.

In contrast, the very small number in the high RNS groupand retrospective study design are important limitations to

this study. A prospective study with a larger sample sizeincluding several in the high RNS group might open thewindow for more widespread use of RNS as a reproducibleand reliable tool for treatment decisions in patients withsmall renal masses.

Yozo Mitsui M.D.

Department of Urology,Shimane University School of Medicine,

Izumo, Japanmitsui@med.shimane-u.ac.jp

DOI: 10.1111/iju.12032

Conflict of interest

None declared.

References

1 Kutikov A, Uzzo RG. The R.E.N.A.L. nephrometry score: acomprehensive standardized system for quantitating renaltumor size, location and depth. J. Urol. 2009; 182: 844–53.

2 Cha EK, Ng CK, Jeun B et al. Preoperative radiographicparameters predict long-term renal impairment followingpartial nephrectomy. World J. Urol. 2011; doi: 10.1007/s00345-011-0694-z.

3 Hayn MH, Schwaab T, Underwood W. RENAL nephrometrysscore predicts surgical outcomes of laparoscopic partialnephrectomy. BJU Int. 2011; 108: 876–81.

4 Bruner B, Breau RH, Lohse CM et al. Renal nephrectomyscore is associated with urine leak after partial nephrectomy.BJU Int. 2010; 108: 67–72.

5 Ellison JS, Montgomery JS, Hafez KS et al. Association ofRENAL nephrometry score with outcomes of minimallyinvasive partial nephrectomy. Int. J. Urol. 2013; 20: 564–70.

6 Kutikov A, Smaldone MC, Egleston BL et al. Anatomicfeatures of enhancing renal masses predict malignant andhigh-grade pathology: a preoperative nomogram using theRENAL Nephrometry score. Eur. Urol. 2011; 60: 241–8.

7 Satasivam P, Sengupta S, Rajarubendra N et al. Renallesions with low R.E.N.A.L nephrometry score areassociated with more indolent renal cell carcinomas (RCCs)or benign histology: findings in an Australian cohort. BJUInt. 2012; 109: 44–7.

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Nephrometry and partial nephrectomy outcomes

© 2012 The Japanese Urological Association 571