[18F]RCCB6 PET/CT in Diagnosing Clear-Cell Renal Cell Carcinomas: A Prospective Comparison Study with [18F]FDG PET/CT and Conventional Imaging

Abstract This single-center prospective phase II trial evaluated [18F]RCCB6 (renal cell carcinoma B6) positron emission tomography (PET)/computed tomography (CT), a cluster of differentiation 70 (CD70)-targeting radiotracer, for detecting metastases in clear-cell renal cell carcinoma (ccRCC). After screening 291 patients, 150 patients with histologically confirmed ccRCC or suspected kidney cancer underwent imaging. Among 1,221 assessable extrarenal lesions, [18F]RCCB6 PET/CT achieved 94.2% sensitivity, 80% specificity, 93.1% accuracy, and 98.3% positive predictive value. In a head-to-head comparison of 99 patients with 683 lesions, [18F]RCCB6 significantly outperformed 2-deoxy-2-[fluorine-18]fluoro-D-glucose ([18F]FDG) PET/CT, with higher diagnostic sensitivity (90.5% vs. 41.1%) and specificity (81.4% vs. 24.3%; both P Significance: This phase II trial demonstrates that [18F]RCCB6 PET/CT significantly outperforms conventional imaging and [18F]FDG PET/CT in detecting metastatic ccRCC, with 94.2% sensitivity and strong correlation with CD70 expression, altering clinical management in 58.7% of patients.