Diagnostic performance of prospectively assigned clear cell Likelihood scores (ccLS) in small renal masses at multiparametric magnetic resonance imaging

Abstract

Introduction: Detection of small renal masses (SRM) is increasing with the use of crosssectional imaging, although many incidental lesions have negligible metastatic potential. A method to identify this subtype would aid in risk stratification. A previously reported clear cell likelihood score (ccLS; 1-very unlikely, 2-unlikely, 3-equivocal, 4-likely, and 5-very likely), based on retrospective review of multiparametric magnetic resonance imaging (mpMRI), predicted the likelihood of encountering clear cell renal cell carcinoma (ccRCC) at surgery. Here, we assess the performance of ccLS prospectively assigned for prediction of ccRCC. Methods: Patients with a known renal mass who underwent mpMRI at a single institution between June 2016 and April 2018 were prospectively assigned a ccLS as part of the clinical MRI report. These patients were retrospectively reviewed, and those with a cT1a lesion and available pathological tissue diagnosis (diagnostic biopsy or extirpative surgery) were selected for analysis. Results: In total, 57 patients (mean age 61.7 ± 14.9 years) with 63 cT1a renal masses were identified. Mean tumor size was 2.7 ± 0.7 cm. Defining ccLS 4-5 lesions as positive demonstrated an overall accuracy of 84%, sensitivity of 89%, specificity of 79%, positive predictive value of 84%, and negative predictive value of 86%. A ccLS of 1-2 demonstrates an 86% accuracy and 100% sensitivity/positive predictive value of identifying non-ccRCC histology.

Multicenter Evaluation of Multiparametric MRI Clear Cell Likelihood Scores in Solid Indeterminate Small Renal Masses

“…the same medical center in which the system was created (23,24). Importantly, although the ccLS algorithm provides a method to assign the likelihood of ccRCC, a subjective component exists in the interpretation of mpMRI studies.…”

Common Subtype of Small Renal Mass MR Imaging Characterisation: A Medical Center Experience in Taiwan

“…Multiparametric MRI has been reported to be helpful in differentiating malignant RCCs from benign lesions in several research studies [9][10][11][12]. However, summaries of the diagnostic values of such parameters have seldom been reported.…”

Canadian Urological Association guideline: Management of small renal masses – Full-text

“…In addition to cryoablation and radio-frequency ablation, there are currently three other types of ablative therapies available to treat SRM: microwave ablation, 44,[104][105][106][107] irreversible electroporation, and stereotactic body radiation therapy (SBRT)…”

“…[108][109][110] Recently, a clear-cell likelihood score has been proposed to determine the risk of a lesion being clear-cell RCC using a non-invasive approach. 104,110,111 This score has been proposed as a tool to reduce the number of patients who undergo routine biopsy and to help guide management, although this remains to be validated.…”