Initial Experience with ⁶⁸Ga-FAP-2286 PET Imaging in Patients with Urothelial Cancer

Area of Science:

• Oncology
• Radiology
• Nuclear Medicine

Background:

• Accurate staging of muscle-invasive bladder cancer (MIBC) and metastatic urothelial carcinoma requires improved imaging techniques.
• Fibroblast activation protein (FAP)-targeted imaging shows promise for detecting various tumors.
• ⁶⁸Ga-FAP-2286 is a novel FAP-peptide binder for PET imaging.

Purpose of the Study:

• To evaluate the efficacy of novel ⁶⁸Ga-FAP-2286 PET imaging in patients with MIBC.
• To assess the sensitivity of ⁶⁸Ga-FAP-2286 in identifying metastatic lesions compared to conventional imaging and ¹⁸F-FDG PET.

Main Methods:

• A clinical trial (NCT04621435) involved 21 patients with histopathologically confirmed bladder cancer (13 localized, 8 metastatic).
• Patients underwent ⁶⁸Ga-FAP-2286 PET imaging; SUV_max and lesion size were recorded.
• Comparison with available ¹⁸F-FDG PET scans (n=5) and conventional CT was performed, with biopsies for discrepancies.

Main Results:

• ⁶⁸Ga-FAP-2286 identified 54 avid lesions (36 metastatic, 18 localized), including subcentimeter lymph nodes.
• Higher SUV_max values were observed for ⁶⁸Ga-FAP-2286 PET compared to ¹⁸F-FDG PET (9.9 vs 4.2).
• ⁶⁸Ga-FAP-2286 PET informed clinical management in 3 patients, identifying false positives on ¹⁸F-FDG PET and false negatives on CT.

Conclusions:

• ⁶⁸Ga-FAP-2286 PET imaging is highly sensitive for urothelial cancer, detecting metastatic lesions across various sites.
• This modality effectively identifies subcentimeter lymph nodes missed by conventional scans.
• ⁶⁸Ga-FAP-2286 PET has the potential to refine staging and guide clinical decisions in MIBC by revealing otherwise undetectable disease.