Virtual renal biopsy: performance of Clear Cell Likelihood Score for renal masses in a referral oncology center in Colombia

Objective: To evaluate the performance of the ccLS (Clear Cell Likelihood Score) in diagnosing clear cell renal cell carcinoma (ccRCC) at a referral oncology center in Colombia. Method: A pilot cross-sectional study was conducted analyzing all adult patients who underwent partial or radical nephrectomy, either metastatic or non-metastatic, between January 2022 and May 2025 at a national referral oncology center. All patients had contrast-enhanced MRI before surgery to assess the ccLS. Two radiologists reviewed the MRIs independently based on the tool ccLS Calculator (www.cclsrads.com). We described demographic characteristics, tumor stage according to American Joint Comittee on Cancer (AJCC) and ccLS results. The score’s performance was assessed using ROC curves. Interobserver agreement between the radiologists was measured with Cohen’s kappa coefficient, with a value > 0.61 indicating substantial agreement. Results: Out of 19 patients, the median age was 63 years (IQR: 49.5-69), with 63% men. Most tumors were stage ≤ cT2 (63%), 79% had no clinical lymph node involvement and no metastasis. About 74% were ccRCC, and 53% had an ISUP grade 2. The ccLS of 4 provided the best balance, with a sensitivity of 92.86%, specificity of 80%, positive predictive value of 92.86% and an area under curve of 0.9. The interobserver agreement was almost perfect, with a kappa of 0.85 (p < 0.0001). Conclusions: The ccLS is an innovative tool in the early stages of implementation that appears to have a high discriminative capacity for scores ≥ 4 in the assessment of ccCCR in renal tumors, showing almost perfect concordance. This could facilitate early oncological approaches and personalized management in the future, avoiding unnecessary invasive interventions. However, larger sample size studies are needed to generalize its use in our context.