LAUSR

INTRODUCTION AND OBJECTIVE definitive inclusion of RMB in SRM diagnostic algorithm remains controversial. We assessed incidence and accuracy of RMB in SRMs in the CROES Renal Mass registry and the influence of preoperative RMB on peri-operative complications after SRM nephron-sparing surgery (NSS). METHODS "ad hoc" description of incidence of preoperative RMB and characteristics of SRM cases with and without RMB. Accuracy of RMB was calculated in the SRM sub-cohort that received extirpative treatment and complication rate after NSS compared between the two groups. Continuous variables were compared using t-test, categorical variables were compared using the chi-square test. K-statistics were used to analyze agreement between the biopsy histology and surgical pathology. Logistic regression was used to assess the association between RMB and NSS complications. All tests were two-sided and P-values <0.05 were considered statistically significant. RESULTS the rate of preoperative RMB in SRMs was 11,6% (175/1597) in Europe and the Americas. RMB-patients were more likely to have hypertension (p<0.04), be on dialysis (p<0.024) or smokers (p=0.005), with multiple/bilateral tumors (0.008 and 0.010) and previous other malignancy (p=0.021). They underwent radical nephrectomy more frequently than non-RMB group (p=0.034). RMB was non-diagnostic in 16 cases [9%]. Accuracy of RMB in distinguishing malignant from benign was 89,5%. Agreement between biopsy and final surgical pathology was 93% for malignant versus benign tumors (Kappa =0.655). Upstaging to pT3a occurred more frequently in the RMB group [12.6% vs 6.25%, (p 0.022)]. Complication rate in RM-NSS sub-cohort was 15.8%, not statistically different between RMB and non-RMB groups. On logistic regression analysis, RMB was not associated with increased risk of postoperative complication after NSS [OR: 0.9, 95% CI: 0.43-1.89]. CONCLUSION . the practice of RMB in SRM is still scarce in spite of high accuracy and concordance with final pathology. RMB does not seem to increase complication rate after NSS.