Molecular Imaging in Gastric Cancer: [¹⁸F]FDG and Fibroblast Activation Protein-Targeted PET/CT

Area of Science:

• Oncology
• Medical Imaging
• Nuclear Medicine

Background:

• Gastric cancer necessitates precise staging and response evaluation for effective treatment.
• Current [¹⁸F]FDG PET/CT has limitations in detecting certain gastric cancer subtypes due to low glucose metabolism.
• Fibroblast activation protein (FAP) imaging targets tumor stroma, offering potential advantages over tumor cell-specific tracers.

Purpose of the Study:

• To review the evolving role of PET/CT in gastric cancer management.
• To compare the diagnostic performance of [¹⁸F]FDG and FAPI PET/CT tracers.
• To explore the potential of FAPI PET/CT in treatment response assessment and theranostics.

Main Methods:

• Review of existing literature on [¹⁸F]FDG PET/CT and FAPI PET/CT in gastric cancer.
• Comparative analysis of diagnostic accuracy and lesion detectability across histological subtypes.
• Evaluation of FAPI uptake in tumor stroma versus tumor cells.

Main Results:

• FAPI PET/CT demonstrates higher sensitivity and consistent uptake across various gastric cancer histological subtypes, including [¹⁸F]FDG-negative tumors.
• FAPI tracers offer superior tumor-to-background contrast compared to [¹⁸F]FDG.
• FAPI PET/CT provides complementary information for treatment response evaluation.

Conclusions:

• FAPI PET/CT enhances diagnostic accuracy in gastric cancer staging and response assessment.
• FAPI tracers represent a promising advancement over [¹⁸F]FDG PET/CT, particularly for challenging subtypes.
• Further prospective studies are required to standardize FAPI PET/CT protocols and confirm its clinical utility.