The Contribution of 68Ga-FAPI-04 PET/CT to Staging and Prognosis in Gastric Cancer

AIM: This study aimed to compare the diagnostic capabilities of 18 F-FDG PET/CT and 68 Ga-FAPI-04 PET/CT imaging in staging gastric carcinoma, exploring the impact of 68 Ga-FAPI-04 PET/CT on treatment planning and its prognostic significance. METHODS: The research included 31 patients undergoing staging for gastric cancer, who received both 18 F-FDG PET/CT and 68 Ga-FAPI-04 PET/CT scans. We compared the SUV max and SUV mean of the primary tumor and lymph nodes, the count of organ metastases, tumor-to-background ratios, and overall staging accuracy. Additionally, the study evaluated radiological progression-free survival and overall survival rates. RESULTS: The 68 Ga-FAPI-04 PET/CT demonstrated superior efficacy in identifying the primary tumor compared with 18 F-FDG PET/CT, particularly in cases of poorly cohesive, signet-ring cell, and mucinous subtypes, with detection rates of 96.7% versus 77.4% ( P = 0.006 and P = 0.008, respectively). Analysis of lymph nodes showed a significantly higher detection of positive nodes with 68 Ga-FAPI-04 ( P = 0.026), although no significant differences were observed in SUV max and tumor-to-background ratio on a patient basis ( P > 0.05). SUV max and tumor-to-background ratios for peritoneal involvement were notably higher with 68 Ga-FAPI-04 PET/CT compared with 18 F-FDG PET/CT ( P = 0.04 for both). No significant differences were found in the detection of organ metastases and disease stage between the 2 imaging modalities ( P > 0.05). Primary tumor uptake did not significantly impact radiological progression-free survival or overall survival in either modality. CONCLUSIONS: 68 Ga-FAPI-04 PET/CT imaging surpasses 18 F-FDG PET/CT in detecting the primary tumor, especially in poorly cohesive and signet-ring cell gastric cancer types, and offers improved accuracy in disease staging. This indicates its potential to enhance treatment management and prognostic assessment in gastric cancer patients.