E5028. Application of a Novel Retroperitoneal Neovascularity Scoring System for Differentiation of T1a Small Renal Masses
  1. Cameron Fateri; University of California, Irvine
  2. Bradley Roth-; ; University of California, Irvine
  3. Sriram Rao; University of California, Irvine
  4. Clifford Danza; University of California, Irvine
  5. Sailesh Wignarajah-; ; University of California, Irvine
  6. Jaime Landman; University of California, Irvine
  7. Roozbeh Houshyar-; ; University of California, Irvine
Early characterization of small (T1a, < 4 cm) renal masses is imperative for patient care and treatment planning. Renal biopsy is a sensitive and specific procedure that can accurately differentiate small renal masses as malignant or benign. However, it is an invasive procedure with a nonnegligible complication rate and is not performed routinely at most institutions. In this study, we sought to apply the Re-VASC scoring system to T1a renal masses and analyzed whether it could differentiate these masses as benign or malignant.

Materials and Methods:
After institutional review board approval, the records of patients who presented to a single, urban academic referral center for surgical treatment of renal cell carcinoma (RCC) from January 13, 2014, to February 4, 2020, were retrospectively examined for inclusion in this study. For the RCC group, patients with diagnosis of T1a RCC from pathologic evaluation were included. Additional inclusion criteria included patients with history of simple or radical nephrectomy, preoperative CT imaging, and available pathology report. The T1a benign group was comprised of patients with a diagnosis of a nonmalignant renal mass (angiomyolipoma or oncocytoma) established via histopathology or CT imaging (fat containing lesions).

A total of 64 benign and 69 malignant T1a renal tumors were included. Comparison of the two groups demonstrated no significant differences with regard to age, sex, ASA, and BMI. The tumor size was 2.373 cm for benign masses and 2.546 cm for malignant masses (p = 0.210). The average Re-VASC scores were 0.159 and 0.753 for benign and malignant masses, respectively (p < 0.001). There was no significant difference in Re-VASC score between the contralateral nontumor bearing kidneys of the RCC and benign groups (p < 0.508). The total range of Re-VASC scores for benign and malignant tumors was 0–2 and 0–4, respectively. Multivariate logistic regression analysis found Re-VASC score (OR: 2.737, p = 0.0079) and tumor size (OR: 1.686, p = 0.0245) to be independent predictors of malignancy.

There is a significant difference in Re-VASC score between malignant and benign T1a renal masses. The Re-VASC score may be utilized as an adjunctive tool in characterizing renal masses, thus improving clinical decision-making and patient outcomes. Future efforts to assess the true efficacy of the Re-VASC score as a diagnostic marker will include prospective evaluation of a larger multicenter population.