Abstract
Accurate diagnosis and staging are crucial for selecting treatment for patients with pancreatic ductal adenocarcinoma (PDAC). The desmoplastic responses associated with PDAC are often characterized by hypometabolism. Here, we investigated (18)F-fibroblast activation protein inhibitor (FAPI)-04 PET/CT in evaluation of PDAC and compared the findings with those obtained using (18)F-FDG. Methods: Sixty-two PDAC patients underwent (18)F-FAPI-04 PET/CT and (18)F-FDG PET/CT. Identification of primary lesions, lymph node (LN) metastasis, and distant metastasis (DM) by these methods was evaluated, and TNM staging was performed. Correlation between SUV(max) of the primary lesion and treatment response was explored in patients who received systemic therapy. Results: (18)F-FAPI-04 PET/CT identified all patients with PDAC; (18)F-FDG PET/CT missed 1 patient. Tracer uptake was higher in (18)F-FAPI-04 PET/CT than in (18)F-FDG PET/CT in primary tumors (10.63 vs. 2.87, P < 0.0001), LN metastasis (2.90 vs. 1.43, P < 0.0001), and DM (liver, 6.11 vs. 3.10, P = 0.002; peritoneal, 4.70 vs. 2.08, P = 0.015). The methods showed no significant difference in the T staging category, but the N and M values were significantly higher for (18)F-FAPI-04 PET/CT than for (18)F-FDG PET/CT (P = 0.002 and 0.008, respectively). Thus, 14 patients were upgraded, and only 1 patient was downgraded, by (18)F-FAPI-04 PET/CT compared with (18)F-FDG PET/CT. A high SUV(max) of the primary tumor did not correlate with treatment response for either (18)F-FAPI-04 or (18)F-FDG. Conclusion: (18)F-FAPI-04 PET/CT performed better than (18)F-FDG PET/CT in identification of primary tumors, LN metastasis, and DM and in TNM staging of PDAC.