Novel retroperitoneal neovascularity scoring system in renal cell carcinoma tumor staging.

Abstract

620 Background: Renal cell carcinoma (RCC) is the most common type of kidney cancer worldwide. While radiologists assess enhancement patterns of renal tumors to predict tumor pathology, to our knowledge, no formal scoring system has been created and validated to assess the level of neovascularity in RCC, despite its critical role in cancer metastases. In this study, we characterized and analyzed the level of angiogenesis in tumor-burdened kidneys and their benign counterparts. We then created and validated a scoring scale for neovascularity that can help predict tumor staging for RCC. Methods: After Institutional Review Board approval, the charts of patients who had undergone surgery for RCC between January 13, 2014 and February 4, 2020 were retrospectively reviewed for inclusion in this study. Inclusion criteria were a diagnosis of RCC, simple/radical nephrectomy, pre-operative contrast enhanced computed tomography (CT) scans, and complete pathology reports. Neovascularity was scored on a scale of 0 to 4 where 0= no neovascularity detected, 1= a single vessel <3mm wide, 2= a single vessel >3mm wide, 3=multiple vessels <3mm wide, and 4=multiple vessels >3mm wide Results: A total of 227 patients were included in the study. The majority of tumor pathology was clear cell carcinoma, regardless of tumor staging. The average neovascularity score was 1.07 for pT1x tumors, 2.83 for pT2x tumors, and 3.04 for pT3x tumors. There was a significant difference in neovascularity score between pT1x and pT2x tumors (p = 0.0046), pT1x and pT3x tumors (p < 0.0001), and benign kidneys and kidneys with RCC (p = <0.0001). Furthermore, we sought to address the ability of the Re-VASC score to predict up-staging or down-staging of clinically staged tumors. Only 5 total tumors were upstaged from cT1 to any pathological stage >1, with an average Re-VASC score of 2.33. There were 24 cases that were down-staged to pT1, with an average Re-VASC score of 1.73. Additionally, we specifically looked at cT3a tumors that were down-staged to p1x. The average Re-VASC scores were 0.82 and 2.11 for pT1a and pT1b tumors respectively. Conclusions: Our novel vascular scoring system for renal cell carcinoma demonstrates significant correlation with RCC pathological tumor staging. In future studies, we would like to further explore the ability of the scoring system to predict clinical up-staging and down-staging, as we had a limited sample size to analyze this function. This scoring system may be utilized as part of a comprehensive radiological assessment of renal tumors, potentially improving tumor characterization and clinical decision making.