Presentation Authors: Hajime Tanaka*, Xiaobo Ding, Yanbo Wang, Yunlin Ye, Rebecca A. Campbell, Molly E. Dewitt-Foy, Chalairat Suk-Ouichai, Ryan D. Ward, Erick M. Remer, Steven C. Campbell, Cleveland, OH
Introduction: To investigate the incidence/significance of infiltrative renal masses (IRMs) in patients undergoing surgery, with focus on IRMs that were not documented as such during radiologic evaluation.
Methods: 541 patients whose surgical specimen demonstrated locally advanced and/or aggressive histology were identified (Figure). Preoperative CT/MRI were retrospectively reviewed to assess for infiltrative features, which were defined as extensive or focal (Figure). All IRMs were required to have poorly defined contour and markedly irregular (non-elliptical) shape in one or more distinct/unequivocal areas.
Results: Image review confirmed 132 IRMs (24%), with 102 RCCs; 39 had sarcomatoid/rhabdoid features, an additional 21 were grade 4, and 18 were unclassified. Twenty-two were high grade urothelial cancers. Median tumor size was 8.2 cm and 92% were high complexity by RENAL. Overall, 104 cases were imaged at our center; 40 were documented as IRM, while infiltrative features were not documented in the remaining 64 (62%). Furthermore, only 4 (6%) of the 64 radiologically undocumented IRM cases were documented as infiltrative by the surgical team. Overall, 101 (77%) patients were symptomatic and 50 (38%) presented with disseminated disease, with no significant difference between IRM documented and undocumented cases. Poorly defined contour and irregular shape were more often focal in IRM undocumented cases (both p < 0.001). With only 25 months median follow-up, 63% of patients recurred and 44% died of IRM with no significant difference between IRM documented and undocumented cases (p=0.60). However, time to IRM-death was significantly shorter in documented IRMs (median: 12 months, versus 25 months in undocumented IRMs; p=0.02). On MVA, extensive poorly defined contour was an independent predictor of increased IRM-specific mortality, while classification of documented vs. undocumented IRM, tumor size/stage/grade, and other radiologic parameters failed to associate.
Conclusions: Almost a quarter of renal tumors with aggressive features were radiological IRM, although many were not documented as IRM. Among this high-risk population, extensive poorly defined contour was an independent predictor of poor outcomes. Our data suggest that infiltrative features should be routinely assessed/documented during evaluation of renal masses.