18F-fluciclovine PET Imaging of Non-PSMA Expressing High-risk Primary Prostate Cancer

Area of Science:

• Oncology
• Nuclear Medicine
• Radiochemistry

Background:

• Prostate cancer staging relies on imaging, with PSMA PET/CT being a key tool.
• Some prostate cancers exhibit low PSMA expression, posing diagnostic challenges.
• Amino acid transporters are upregulated in certain cancers.

Purpose of the Study:

• To evaluate the utility of 18F-fluciclovine PET/CT in staging a primary prostate cancer with confirmed low PSMA expression.
• To investigate the correlation between amino acid transporter expression and imaging findings in this specific case.

Main Methods:

• Case report of a 67-year-old man with high-grade prostate cancer (Gleason score 9, grade group 5).
• Initial staging with 18F-DCFPyL (PSMA) PET/CT showed minimal avidity.
• Off-label staging and management guidance using 18F-fluciclovine PET/CT.
• Immunohistochemistry to assess PSMA and amino acid transporter expression.

Main Results:

• The primary prostate tumor, despite low PSMA avidity on 18F-DCFPyL PET/CT, demonstrated intense uptake on 18F-fluciclovine PET/CT.
• Immunohistochemistry confirmed high expression of amino acid transporters and low PSMA expression in the tumor.
• This imaging pattern guided management decisions.

Conclusions:

• 18F-fluciclovine PET/CT can be an effective off-label alternative for staging primary prostate cancer in cases with minimal PSMA expression.
• The findings underscore the importance of considering alternative PET tracers when PSMA-targeted imaging is inconclusive.
• This highlights the potential of targeting amino acid transporters in specific prostate cancer subtypes.