1. Conferences Overview
    2. 52. Tagung der Bayerischen Urologenvereinigung und der Österreichischen Gesellschaft für Urologie und Andrologie
    3. Prospective evaluation of [68Ga]-FAPI-PET/MRI for loco-regional staging of muscle-invasive bladder cancer
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52. Tagung der Bayerischen Urologenvereinigung und der Österreichischen Gesellschaft für Urologie und Andrologie


06.-08.05.2026
Würzburg

Meeting Abstract

Prospective evaluation of [68Ga]-FAPI-PET/MRI for loco-regional staging of muscle-invasive bladder cancer

Ekaterina Laukhtina - Medical University of Vienna, Department of Urology, Vienna, Austria
Shahrokh F. Shariat - Medical University of Vienna, Department of Urology, Vienna, Austria
Melanie Hassler-Di Fratta - Medical University of Vienna, Department of Urology, Vienna, Austria
Marcus Hacker - Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Devision of Nuclear Medicine, Vienna, Austria
Dina Muin - Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Devision of Nuclear Medicine, Vienna, Austria

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Introduction: Fibroblast activation protein (FAP) is frequently overexpressed by cancer-associated fibroblasts in various tumor types, including bladder cancer. This study aimed to evaluate the performance of [68Ga]-FAPI-PET imaging for loco-regional staging in patients with MIBC.

Methods: In this prospective investigator-initiated study, consecutive MIBC patients planned for RC were enrolled. All patients underwent both [68Ga]-FAPI-PET/MRI and standard [18F]-FDG-PET/CT prior to NAC and again prior to RC. The primary outcome of interest was the diagnostic accuracy of [68Ga]-FAPI-PET/MRI and/or [18F]-FDG-PET/CT for local and nodal staging in MIBC patients. The specificity, sensitivity, PPV, and NPV of imaging modalities for local and nodal staging were assessed, with pathology results at RC serving as the reference test.

Results: We included twenty-two MIBC patients treated with RC; among them, fourteen (64%) received NAC. Fifteen patients (68%) had residual bladder tumor at RC. In ten patients, [68Ga]-FAPI demonstrated significant expression in the primary tumor located in the bladder wall, resulting in a sensitivity of 60%, specificity of 85%, PPV of 89%, and NPV of 50%. Similarly, [18F]-FDG-PET/CT demonstrated a sensitivity of 60%, specificity of 100%, PPV of 100%, and NPV of 54% for primary tumor detection. The median number of removed lymph nodes was 32 (range 2 to 78). Seven patients (32%) had lymph node metastases on the RC pathology report. For lymph node detection, [68Ga]-FAPI-PET/MRI and [18F]-FDG-PET/CT resulted in identical sensitivity (33%), specificity (93%), PPV(69%), and NPV (75%).

Conclusion: In this study, [68Ga]-FAPI-PET/MRI demonstrated similar diagnostic accuracy to [18F]-FDG-PET/CT for locoregional tumor staging in MIBC patients; both modalities had a moderate sensitivity but high specificity for detecting primary tumors and lymph node metastases. These findings indicate that [68Ga]-FAPI-PET could be a viable alternative imaging tool for MIBC staging, though both imaging modalities/tracers underperform for ruling out a cancer. Further studies are needed to validate [68Ga]-FAPI-PET’s reliability and clinical utility.