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

This single-center prospective phase II trial evaluated [18F]RCCB6 PET/CT, a 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 extra-renal lesions, [18F]RCCB6 PET/CT achieved 94.2% sensitivity, 80.0% 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 [18F]FDG PET/CT, with higher diagnostic sensitivity (90.5% vs. 41.1%) and specificity (81.4% vs. 24.3%; both P < 0.001). Compared with conventional imaging across 748 lesions, [18F]RCCB6 PET/CT also demonstrated superior sensitivity (90.8% vs. 75.1%) and specificity (81.6% vs. 56.6%). [18F]RCCB6 uptake (SUVmax) strongly correlated with CD70 expression (r = 0.843, P < 0.001). Moreover, the imaging findings changed clinical management in 58.7% of patients. [18F]RCCB6 PET/CT is a highly sensitive imaging modality for diagnosing ccRCC metastases and informing clinical decision-making.