Introduction: Renal sinus involvement and calyces invasion may jeopardize surgical and oncological outcomes in case of underperformance of standard imaging. In the current study, we analyzed the concordance between preoperative imaging and final pathology in a large series of patients undergoing nephrectomy for Renal Cell Carcinoma (RCC). Methods: We included 346 consecutive patients who were treated with RN for non-metastatic RCC. Two expert urologists prospectively reviewed all CT scans. One dedicated genito-urinary pathologist prospectively reviewed every single kidney specimen blinded to axial imaging characteristics. 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: Median clinical tumor size was 70 mm (Interquartile range [IQR ]: 55-89 mm). The rate of renal sinus involvement was 76% and the concordance rate between radiological score and pathological report was 44%. Rates of over- and underestimation were 65% and 20%, respectively. At LRM, after adjusting for every PADUA item, no correlation between renal sinus involvement at imaging and renal sinus infiltration at pathology was found (OR 0.76, 95 % CI 0.09-4.37; p=0.8). Of 256 patients in whom calyces invasion was detected, concordance between radiological imaging and final pathology was recorded in 46% patients. Rates of over- and underestimation were 94% and 3%. Conclusions: At final pathology after RN, sinus involvement and calyces invasion are not confirmed in more than one case out of two. Specifically, such discordance has two major clinical implications: radiological overestimation may exclude conservative surgical approaches leading to a non-negligible risk of overtreatment. Secondly, radiological underestimation of renal sinus infiltration may lead to more conservative treatment approaches in patients, potentially jeopardizing oncological outcomes in terms of positive surgical margins, local recurrence and clinical progression. SOURCE OF Funding: None
