MP55-10 PEDIATRIC SMALL RENAL MASSES: CAN TUMOR SIZE PREDICT HISTOLOGY AND THE POTENTIAL FOR NEPHRON-SPARING SURGERY?

Abstract

You have accessJournal of UrologyPediatric Urology V (MP55)1 Sep 2021MP55-10 PEDIATRIC SMALL RENAL MASSES: CAN TUMOR SIZE PREDICT HISTOLOGY AND THE POTENTIAL FOR NEPHRON-SPARING SURGERY? Daniel Han, Peter Boxley, Andrew Nicklawsky, Nina Mikkilineni, Sarah Hecht, Amanda Saltzman, Nicholas Cost, and Jonathan Walker Daniel HanDaniel Han More articles by this author , Peter BoxleyPeter Boxley More articles by this author , Andrew NicklawskyAndrew Nicklawsky More articles by this author , Nina MikkilineniNina Mikkilineni More articles by this author , Sarah HechtSarah Hecht More articles by this author , Amanda SaltzmanAmanda Saltzman More articles by this author , Nicholas CostNicholas Cost More articles by this author , and Jonathan WalkerJonathan Walker More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002085.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The majority of children with non-syndromic, unilateral renal masses suspicious for malignancy undergo radical nephrectomy (RN). Nephron-sparing surgery (NSS) is reserved for patients with bilateral Wilms tumor (WT), predisposition syndromes, solitary kidney, or select non-WT histologies. While mostly curative, RN can have significant long-term health consequences. Prior review of SEER data showed that pediatric small renal masses (SRM) are less likely to be WT. In this study, we investigate our institutional data to determine how tumor size (TS) impacted the probability of finding WT on final pathology. We hypothesize that SRM are more likely to have benign or non-WT histology, and thus are potentially appropriate for NSS. METHODS: A retrospective review was performed of patients who underwent RN or NSS for a unilateral renal mass at a single institution from 2005-2019. Patients who received neoadjuvant chemotherapy and those with unknown final histology were excluded. We utilized 4 cm (the accepted definition of a SRM in adults), as the optimal size cut-point to predict WT. Statistical analysis was performed to describe the predictive characteristics of preoperative TS (<4cm vs ≥4cm) on final histology. Histologies deemed appropriate for RN were WT, clear cell sarcoma of the kidney, and rhabdoid tumor of kidney, while those deemed appropriate for NSS were renal cell carcinoma or benign histology. Finally, we analyzed if preoperative TS on imaging correlated with TS on final pathology. RESULTS: 134 patients met inclusion criteria. 97 (72.3%) tumors were WT. There were 12 tumors <4 cm. Tumors ≥4cm compared to tumors <4cm had a significantly higher likelihood of being WT vs non-WT (OR 17.54, 95% CI 3.53, 87.22), of being malignant vs benign (OR 4.73, 95% CI 1.34, 16.72), and of having RN-appropriate histology vs NSS-appropriate histology (OR 30.42, 95% CI 5.92, 156.3). There was a strong positive Spearman correlation of 0.87 (p<0.0001) between preoperative imaging TS and postoperative pathology TS. CONCLUSIONS: The probability that a pediatric renal mass is WT increases with TS. 4cm is a logical cut-point that can be used to define a pediatric SRM. This cut-point may be able to predict the probability of WT and determine patient eligibility for diagnostic NSS and intraoperative FS. Source of Funding: University of Colorado Cancer Center Support Grant (P30CA046934) © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e962-e962 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Daniel Han More articles by this author Peter Boxley More articles by this author Andrew Nicklawsky More articles by this author Nina Mikkilineni More articles by this author Sarah Hecht More articles by this author Amanda Saltzman More articles by this author Nicholas Cost More articles by this author Jonathan Walker More articles by this author Expand All Advertisement Loading ...