From PADUA to R.E.N.A.L. Score and Vice Versa: Development and Validation of a Mathematical Converter

Abstract

Tumor complexity remains the primary modality by which urologists determine surgical approach and treatment strategy. R.E.N.A.L. and PADUA scores are the most popularly used nephrometry systems. Notwithstanding the common items contributing to the scores, some differences exist between PADUA and R.E.N.A.L. systems, translating into a different final score when assessing the tumor complexity of a renal mass. This represents an issue during quantitative syntheses of literature data and in the setting of retrospective multicentric analyses. We aimed to develop a PADUA-to-R.E.N.A.L. score mathematical converter and vice versa, from a dataset of 488 renal masses who had data about PADUA score, R.E.N.A.L. score and clinical tumor size. PADUA score was modeled as proportional, through a scalar coefficient, to the R.E.N.A.L. score, to obtain the calculated PADUA score (cPADUA=1.14225 × R.E.N.A.L.). Vice versa, the calculated RENAL score (cR.E.N.A.L. = 0.8607 ×PADUA) was obtained (adjusted R2 = 0.9831, p = 0.000003). Descriptive statistics of mathematically calculated distributions matched with the real values. A 5-fold cross-validation scheme was used to validate the model.