Pilot Comparison of 18F-FP-R01-MG-F2 and 18F-FDG PET in Patients with Pancreatic Cancer

1004 Purpose: A new cystine knot PET tracer, 18F-FP-R01-MG-F2, has been shown to selectively bind to human integrin αvβ6. This integrin cell surface receptor is over-expressed in pancreatic cancer, as well as other cancers. Here, we compared the tumor uptake of 18F-FP-R01-MG-F2 with 18F-FDG in patients with pancreatic cancer. Methods: Seven patients (1 man, 6 women) with histologically confirmed pancreatic cancer were prospectively enrolled between March 2017 and November 2019. All patients underwent an 18F-FP-R01-MG-F2 PET/CT scan and 18F-FDG PET/CT scan within 3 weeks of each other. Maximum standardized uptake values (SUVmax), mean SUV (SUVmean), and tumor-to-normal tissue (T/N) ratios of known or suspected cancer lesions detected by both 18F-FP-R01-MG-F2 and 18F-FDG PET were compared on a per-lesion based analysis. Results: 18F-FP-R01-MG-F2 PET detected known pancreatic tumors in all 7 patients. Of the four patients with lymph node metastases confirmed by surgery (n = 1) or suspected by contrast-enhanced CT (n = 3), each PET scan detected lymph node metastases in three patients but failed to detect them in one different patient. Compared with 18F-FDG, 18F-FP-R01-MG-F2 had significantly higher T/N ratios in liver metastases (n = 27, 4.3 ± 1.4 vs. 1.5 ± 0.3, P 0.30). In two patients with lung metastases without significant 18F-FDG uptake, 18F-FP-R01-MG-F2 showed significant uptake, although T/N ratios could not be compared due to small sample size. There was weak correlation between uptake values from 18F-FP-R01-MG-F2 and 18F-FDG (ρ = 0.40 & ρ = 0.30 for SUVmax and SUVmean, respectively). Conclusions: Staging of pancreatic cancer with 18F-FP-R01-MG-F2 PET is feasible. 18F-FP-R01-MG-F2 PET was superior to 18F-FDG PET in detecting lung and liver metastases and had a higher lesion conspicuity (T/N ratio) for liver metastases. The weak correlation between 18F-FP-R01-MG-F2 and 18F-FDG uptake suggests that the biological information provided by each PET tracer is different.