PD40-10: Formal validation at final pathology after radical nehrectomy of nephrometry scores: discordance rates and overtreatment risk

Francesco Cei*, Giacomo Musso, Giuseppe Rosiello, Giuseppe Fallara, Daniele Cignoli, Giuseppe Basile, Gianmarco Colandrea, Gianfranco Baiamonte, Federico Belladelli, Isaline Rowe, Daniela Canibus, Chiara Re, Roberta Lucianò, Maurizio Colecchia, Francesco De Cobelli, Giorgio Brembilla, Milan, Italy, Federico Dehò, Varese, Italy, Vincenzo Mirone, Naples, Italy, Alberto Briganti, Roberto Bertini, Francesco Montorsi, Andrea Salonia, Alessandro Larcher, Umberto Capitanio, Milan, Italy

Introduction: International guidelines support the use nephrometry scores to measure the anatomical complexity of renal masses and improve clinical decision-making. Since nephrometry scores have been applied to partial nephrectomy (PN) cases only, no formal histologic validation on radical nephrectomy specimen (RN) is available. Our hypothesis states that radiologic characteristics at axial imaging may not be invariably confirmed at final pathology

Methods: The study population consists of 116 patients treated with RN for cM0 renal cancer. Two expert urologists blinded to final pathology reviewed CT scans and classified each case according to established nephrometry scores (PADUA and SPARE). Concordance rates with final pathological reports were calculated with a specific focus on renal sinus involvement and calyces invasion. Finally, we relied on multivariable logistic regression analyses (LRM) to validate the results

Results: Mean age was 61 years (interquartile range [IQR]: 52-72.7). Mean clinical tumor size was 85 mm. Mean PADUA was 10. The rate of renal sinus involvement was 33% and the concordance rate between radiological score and pathological report was 38%. Rates of over- and underestimation were 53% and 9%, respectively. At LRM, no correlation between nephrometry score and renal sinus involvement was found (OR 0.76, 95 %CI 0.31-1.92; p=0.5). Of 49 patients in whom calyces invasion was evaluated, concordance between radiological imaging and final pathology was recorded in 53% patients. Rates of over- and underestimation were 70% and 30%. Finally, at LRM no correlation between nephrometry score and calyxes invasion was demonstrated (OR 1.52, 95%CI 0.46-5.19; p= 0.4)

Conclusions: At final pathology after RN, anatomical characteristics of nephrometry measured at axial imaging such as sinus involvement and calyces invasion are not confirmed in 1 case out of 2. Specifically, such discordance rate is even higher when evaluating renal sinus involvement (62%) relative to calyxes invasion (47%). Based on this data, caution is urged when PN is excluded preoperatively based nephrometry scores since this indication imply a non-negligible risk of overtreatment

Source of Funding: no