Comparison of 68Ga-FAPI PET/CT and 18F-FDG PET/CT in gastric cancer: impact on metastatic detection and stage migration.

Abstract

ObjectivesTo compare the diagnostic performance of 18F-fluorodeoxyglucose (18F-FDG) PET/CT and ⁶⁸Ga-FAPI PET/CT in patients with gastric cancer, with particular emphasis on metastatic detection and stage migration.MethodsFifty-two patients with histopathologically confirmed gastric cancer who underwent both 18F-FDG PET/CT and ⁶⁸Ga-FAPI PET/CT were retrospectively analyzed. Primary tumor uptake, metastatic involvement, and tumor staging were evaluated for each modality. Detection rates for lymph node, peritoneal, liver, and bone metastases were compared. Diagnostic performance and stage migration between modalities were assessed. Quantitative parameters including standardized uptake value and tumor-to-background ratio were analyzed.Results⁶⁸Ga-FAPI PET/CT demonstrated significantly higher uptake in primary tumors compared with 18F-FDG PET/CT (P Conclusion: ⁶⁸Ga-FAPI PET/CT improves detection of metastatic disease, particularly peritoneal involvement, compared with 18F-FDG PET/CT in patients with gastric cancer and may contribute to more accurate disease staging.Advances in knowledgeThis study highlights the added value of 68Ga-FAPI PET/CT in identifying metastatic disease and altering clinical staging, particularly through improved detection of peritoneal involvement, which may impact treatment decision-making.