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Background It was difficult to compare the outcome of partial nephrectomy among different studies due to the absence of standardized description of different renal masses. This problem led to the development of nephrometry scoring systems. R.E.N.A.L. is among the commonest nephrometry scoring systems; however, some studies failed to find any relation between R.E.N.A.L. with perioperative outcome. We evaluated our designed newly modified nephrometry score in prediction of outcome following partial nephrectomy and compared its predictability versus original R.E.N.A.L. Methods Fifty-one patients with cT1-2N0M0 renal masses amenable for partial nephrectomy were included prospectively. Different perioperative outcome variables were compared according to complexity level in R.E.N.A.L. and the newly modified nephrometry score. Results Clinical staging was T1a (21.6%), T1b (49%), T2a (25.5%), T2b (3.9%). Median R.E.N.A.L. was 9 (4–12). Hilar position and intrarenal pelvis were detected in 19.6% and 68.6%. Low, moderate and high complexity masses were found in 21.6%, 39.2% and 39.2%. Complications and rate of conversion to radical nephrectomy were 17 (33.3%) and 4 (7.8%). The only significantly affected variable (p = 0.039) by R.E.N.A.L. was rate of secondary intervention, but it was higher in low than in high complexity level. In the newly modified nephrometry score, complications (p = 0.037) and rate of positive surgical margin (p = 0.049) were significantly higher with increased complexity level. Although other variables (pelvi-calyceal system entry, operative time, blood loss, hemoglobin loss, blood transfusion and conversion to radical nephrectomy) did not show statistically significant difference according to both scores, they were better associated with the complexity level in the newly modified nephrometry score with their remarkable increase in the high when compared to the low complexity level. Conclusions The newly modified nephrometry score was associated with better prediction of outcome of partial nephrectomy when compared to R.E.N.A.L.

Background and Aims: To evaluate simple tumor characteristics (renal tumor diameter and parenchymal invasion depth) compared with more complex classifications, that is, Renal Tumor Invasion Index (RTII) and Preoperative Aspects and Dimensions Used for an Anatomical classification, in predicting the type of nephrectomy (radical vs partial) performed. Material and Methods: A total of 915 patients who had undergone either partial nephrectomy ( n = 388, 42%) or radical nephrectomy ( n = 527, 58%) were identified from the Helsinki University Hospital kidney tumor database between 1 January 2006 and 31 December 2014. Tumor maximum diameter and depth of invasion into the parenchyma were estimated from computed tomography or magnetic resonance imaging images and compared with Preoperative Aspects and Dimensions Used for an Anatomical and Renal Tumor Invasion Index. Logistic regression and receiver operating curves were used to compare the parameters at predicting the type of nephrectomy. Results and conclusion: All the anatomical variables of receiver operating curve/area under the curve analyses were significant predictors for the type of nephrectomy. Parenchymal invasion (area under the curve 0.91; 95% confidence interval, 0.89–0.93), RTII (area under the curve 0.91; 95% confidence interval, 0.89–0.93), and diameter (area under the curve 0.91; 95% confidence interval, 0.89–0.93) performed significantly better than Preoperative Aspects and Dimensions Used for an Anatomical classification (area under the curve 0.88; 95% confidence interval, 0.85–0.89). In multivariable analysis, invasion depth was the best predictor of nephrectomy type (percentage correct, 85.6%). Addition of one anatomic parameter into the model of non-anatomical cofactors improved the accuracy of the model significantly, but the addition of more parameters did not. Parenchymal invasion depth and tumor diameter are the most accurate anatomical features for predicting the nephrectomy type. All potential anatomical classification systems should be tested against these two simple characteristics.

ResumenIntroducciónEl sistema de nefrometría R.E.N.A.L., desarrollado como herramienta imagenológica de abordaje terapéutico para masas renales sólidas permite la evaluación reproducible y cuantitativa de sus características anatómicas.MetodologíaSe analizaron retrospectivamente los resultados histopatológicos, así como las implicaciones quirúrgicas y complicaciones en 38 pacientes del CMN 20 de Noviembre, sometidos a cirugía preservadora de nefronas por masas renales sólidas. Se calculó el grado de complejidad de las masas renales de acuerdo al sistema de nefrometría R.E.N.A.L. subdividiendo la muestra en 3 subgrupos, baja (4-6), moderada (7-9) y alta complejidad (10-12)ResultadosSe estableció una correlación positiva entre la complejidad radiológica de la masa tumoral con el grado histológico de Fuhrman (0.8283, IC 95% 0.6918-0.9076), con la cantidad de hemorragia transoperatoria (0.7073, IC 95% 0.5009-0.8376), el tiempo requerido de isquemia transoperatoria (0.6627, IC 95% 0.4352-0-0.8107) y la tasa global de complicaciones derivadas del procedimiento quirúrgico. (0.5944, IC 95% 0.3392-0.7681).ConclusionesDe acuerdo a los resultados obtenidos, se evidencia la correlación de implicaciones quirúrgicas con el grado de complejidad radiológica en masas renales. Su reproductibilidad y accesibilidad la convierten en una herramienta útil para predicción de resultados quirúrgicos e incluso de impacto a nivel oncológico en el manejo de masas renalesAbstractBackgroundThe R.E.N.A.L. Nephrometry Scoring System was developed as an imaging tool in the therapeutic approach to solid renal masses that enables a reproducible and quantitative evaluation of their anatomic characteristics.MethodsThe surgical implications, complications, and histopathologic results were retrospectively analyzed in 38 patients that underwent nephron-sparing surgery for solid renal masses at the CMN 20 de Noviembre. The grade of complexity of the renal masses was calculated according to the R.E.N.A.L. Nephrometry Scoring System, subdividing the sample into 3 tumor complexity subgroups: low (4 to 6), moderate (7 to 9), and high (10 to 12)ResultsThere was a positive correlation between radiologic tumor complexity and the Fuhrman histologic grade (0.8283, 95%CI 0.6918-0.9076), intraoperative blood loss (0.7073, 95%CI 0.5009-0.8376), required intraoperative ischemia time (0.6627, 95%CI 0.4352-0-0.8107), and overall surgical complication rate (0.5944, 95%CI 0.3392-0.7681).ConclusionsOur results showed a correlation between surgical implication and radiologic complexity grade in renal masses. The reproducibility of and access to this tool make it useful in the prediction of surgical results, along with its having an impact on renal mass oncologic management.