Evaluation of a novel Re-VASC score to differentiate malignant and benign T1a renal masses.

Abstract

e16548 Background: Early characterization of renal cell carcinoma (RCC) is pertinent for cancer prognosis and patient treatment. However, characterization of renal masses as benign or malignant on computed tomography (CT) remains a difficult clinical challenge. Angiogenesis plays a major role in RCC progression and assessing neovascularity in tumor-burdened kidneys with Re-VASC scoring has been shown to aptly predict tumor pathology and staging. In the current study, we evaluated if Re-VASC can reliably differentiate between malignant T1a ( < 4cm) RCC and benign T1a renal masses. Methods: All eligible patients had a diagnosis of T1a from pathologic or clinical evaluation. The inclusion criteria for malignant masses included a diagnosis of RCC by pathology after partial or radical nephrectomy. Our T1a benign group was comprised of patients with a diagnosis of a non-malignant renal mass (angiomyolipoma or oncocytoma) established via histopathology or CT imaging (fat containing lesions). Re-VASC score was calculated on axial preoperative contrast enhanced CT utilizing the system described below: 0 = No visible neovascularization 1 = visualized single new vessel < 3mm in diameter 2 = visualized single new vessel ≥3mm in diameter 3 = visualized multiple new vessels < 3mm in diameter 4 = visualized multiple new vessels and at least one vessel ≥3mm in diameter. Results: A total of 64 benign and 69 malignant T1a tumors were included. Comparison of the two groups demonstrated no significant differences with regards to age, sex, ASA, and BMI. The average Re- VASC scores was 0.159 and 0.753 for benign and malignant masses respectively (p < 0.001). Additionally, the tumor size for benign masses was 2.373 and for malignant masses was 2.546 (p = 0.210). There was no significant difference in Re-VASC score between the contralateral kidneys of malignant and benign kidney masses (p < 0.508). Additionally, the sensitivity, specificity and positive predictive values were 26%, 86% and 74% respectively, when utilizing a Re-VASC score of 1 as a cutoff for malignancy. Conclusions: Our results show a significantly higher Re-VASC score in T1a malignant tumors and T1a benign tumors. While biopsy remains the gold standard for confirmation of malignant tumors such as RCC, radiological evaluation with tumor scoring systems like Re-VASC may offer a useful clinical decision-making tool in a less-invasive manner. Because renal biopsy carries non-negligible risk of complications, reducing volume of biopsies among low-risk patients may lead to better overall care. The Re-VASC score shows potential as a confirmatory test with a specificity of 86%. We would like to apply the Re-VASC score to an expanded multi-center trial, in order to assess its translatability to the general population.