Low complexity lesions on R.E.N.A.L. nephrometry are associated with more indolent histology

1. No. 072 Low complexity lesions on R.E.N.A.L. nephrometry are associated with more indolent histology P Satasivam, S Sengupta, N Rajarubendran, PH Chia, A Munshey, D Bolton The Austin Hospital, Heidelberg VIC • Introduction • Radical nephrectomy (RN) may lead to the development of chronic kidney disease and its complications, hence the recommendation for nephron-sparing surgery (NSS) where possible. • The R.E.N.A.L. nephrometry score is an objective measure of factors important in determining suitability for NSS, such as size, exophytic nature, proximity to collecting system and polar location. • At present, tumour size is the only established preoperative variable that helps predict the malignant potential of incidentally-detected renal masses, in the absence of biopsy. • Results • The rate of benign pathology decreased with increasing lesion complexity (p = 0.09). • Among RCC, there was a significant association between higher complexity and higher rate of adverse features . . . • . . . and conversely a lower rate of favourable prognostic features. • Aims • To assess the relationship of nephrometry score to the histological features of lesions treated by surgical excision. • Methods • Retrospective review of renal masses treated by surgery from January 2005 to December 2009, including 79 RN and 70 NSS. • CT images available for analysis in 50 patients within each group. • Lesions were scored on the basis of their complexity using the R.E.N.A.L. nephrometry scoring system developed by Kutikov and Uzzo. • Comparisons made using Chi-square or Fisher's exact tests, with statistical significance ascribed to p<0.05. • Discussion • Kutikov et al, 2011. • Nephrometry score correlated with both tumour grade ( p < 0.0001) and histology ( p < 0.0001) • small endophyticnonhilar tumours were more likely to represent benign pathology • Conversely, large interpolar and hilar tumours more often represented high-grade cancers • Satasivam et al, 2011. • NSS performed predominantly for low complexity lesions (92%) • Oncocytoma detected in 19% of patients undergoing NSS compared with only 4% of RN patients • Venkatesh et al, 2006. • Of 123 laparoscopic PN (mean size 2.6 cm), only 55% of highly exophytictumours were malignant and of those 96% were invariably low grade References Kutikov A , Uzzo RG . The R.E.N.A.L. Nephrometry Score: a comprehensive standardized system for quantitating renal tumor size, location and depth . J Urol 2009 ; 182 : 844 – 53. Kutikov A, et al. Anatomic features of enhancing renal masses predict malignant and high-grade pathology: a preoperative nomogram using the RENAL Nephrometry score. Eur Urol.  Aug: 60:241-8. • Conclusions • Anatomical features of RCC may provide a predictive insight into tumour biology, and aid preoperative decision-making. • In essence a low-complexity renal lesion should undergo NSS, not just because of the benefits of renal preservation, but also because it is more likely to be indolent. Poster presentation sponsor