Re: Dinesh K. Agarwal, Clancy Mulholland, Digsu N. Koye, et al. RPN (Radius, Position of Tumour, Invasion of Renal Sinus) Classification and Nephrometry Scoring System: An Internationally Developed Clinical Classification To Describe the Surgical Dif

Agarwal and colleagues [1] introduced a novel classification system (radius, position of tumour, invasion of renal sinus; RPN) that offers a unique approach to predicting the preoperative surgical difficulty of renal masses scheduled for robot-assisted partial nephrectomy (RAPN).None of the previously described nephrometry systems used such an approach.While RENAL and PADUA have been the most popular and widely used scores for predicting perioperative outcomes of partial nephrectomy, the authors argue that correlations using these first-generation scoring systems have become clinically irrelevant in modern RAPN practice.Experienced surgeons now successfully perform partial nephrectomy for highly complex tumours and achieve perioperative outcomes comparable to those for low-complexity tumours.The authors convincingly argue that RENAL and PADUA scores are highly inconsistent in predicting meaningful perioperative outcomes for RAPN.Two recent large series also support their views [2,3].These observations raise serious concerns about the utility of first-generation nephrometry scoring systems in reporting data from RAPN series.Although perioperative outcomes may not be worse for high-complexity tumours, these tumours present greater surgical challenges for resection.Therefore, a surgical difficulty score such as the RPN system offers a more precise and sensible means for accurately assessing the complexity of these tumours.The authors emphasise that perioperative outcomes of partial nephrectomy can vary depending on whether the surgical approach chosen was open, laparoscopic, or robotic.Several studies indicate that RAPN has a superior morbidity profile in comparison to laparoscopic and open approaches [4,5].Since none of the first-generation scoring systems were developed specifically for the robotic approach, use of these scores for reporting may not accurately represent perioperative outcomes, and thus their utility in such data reporting is not scientifically justified.The RPN scoring system stands out for its simplicity, with the use of only three parameters to classify tumour complexity.This simplicity does not compromise accuracy; instead, it enhances practicality and applicability in realworld settings.The RPN system emerges as a highly suitable and practical tool and should replace the popular RENAL and PADUA systems in future reporting of RAPN series.