Role of CuCl PET/CT in Detecting and Staging Muscle-Invasive Bladder Cancer: Comparison with Contrast-Enhanced CT and F-FDG PET/CT.

Molecular imaging of muscle-invasive bladder cancer (MBC) is restricted to its locoregional and distant metastases, since most radiopharmaceuticals have a urinary excretion that limits the visualization of the primary tumor. CuCl a positron-emitting radiotracer with nearly exclusive biliary elimination, could be well suited to exploring urinary tract neoplasms. In this study, we evaluated the feasibility of CuCl-based staging of patients with MBC; furthermore, we compared the diagnostic capability of this method with those of the current gold standards, that is, contrast-enhanced CT (ceCT) and F-FDG PET/CT. We prospectively enrolled patients referred to our institution for pathology-confirmed MBC staging/restaging between September 2021 and January 2023. All patients underwent ceCT, F-FDG, and CuCl PET/CT within 2 wk. Patient-based analysis and lesion-based analysis were performed for all of the potentially affected districts (overall, bladder wall, lymph nodes, skeleton, liver, lung, and pelvic soft tissue). Forty-two patients (9 women) were enrolled. Thirty-six (86%) had evidence of disease, with a total of 353 disease sites. On patient-based analysis, ceCT and CuCl PET/CT showed higher sensitivity than F-FDG PET/CT in detecting the primary tumor ( < 0.001); moreover, CuCl PET/CT was slightly more sensitive than F-FDG PET/CT in disclosing soft-tissue lesions ( < 0.05). Both PET methods were more specific and accurate than ceCT in classifying nodal lesions ( < 0.05). On lesion-based analysis, CuCl PET/CT outperformed F-FDG PET/CT and ceCT in detecting disease localizations overall ( < 0.001), in the lymph nodes ( < 0.01), in the skeleton ( < 0.001), and in the soft tissue ( < 0.05). CuCl PET/CT appears to be a sensitive modality for staging/restaging of MBC and might represent a "one-stop shop" diagnostic method in these scenarios.