Clinical Utility of F-18 Labeled Fibroblast Activation Protein Inhibitor (FAPI) for Primary Staging in Lung Adenocarcinoma: a Prospective Study

• Published in: Molecular imaging and biology Vol. 24; no. 2; pp. 309 - 320
• Main Authors: Li, Youcai, Lin, Xinqing, Li, Yi, Lv, Jie, Hou, Peng, Liu, Shaoyu, Chen, Penghao, Wang, Min, Zhou, Chengzhi, Wang, Xinlu
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.04.2022; Springer Nature B.V
• Subjects: Adenocarcinoma; Adenocarcinoma of Lung - diagnostic imaging; Bones; Brain; Cancer; Computed tomography; Fibroblast activation protein; Fibroblasts; Fluorine isotopes; Fluorodeoxyglucose F18; Gallium Radioisotopes; Humans; Imaging; Inhibitors; Lesions; Lung cancer; Lung Neoplasms - diagnostic imaging; Lungs; Lymph nodes; Lymphatic system; Magnetic resonance imaging; Medicine; Medicine & Public Health; Neuroimaging; Patients; Pleura; Positron emission; Positron emission tomography; Positron Emission Tomography Computed Tomography; Prospective Studies; Proteins; Radioisotopes; Radiology; Rank tests; Research Article; Tomography; Tumors; F]F-FAPI; Lung adenocarcinoma; [; Lesions; F]F-FDG; [18F]F-FAPI; [18F]F-FDG
• ISSN: 1536-1632; 1860-2002; 1860-2002
• DOI: 10.1007/s11307-021-01679-w

Purpose The purpose of this study was to compare the primary staging of F-18 labeled fibroblast activation protein inhibitor ([ 18 F]F-FAPI) with that of F-18 labeled fluordesoxyglucose positron emission tomography/computed tomography ([ 18 F]F-FDG PET/CT) in patients with lung adenocarcinoma (LAD). Procedures We prospectively analyzed the images of LAD patients who underwent [ 18 F]F-FAPI and [ 18 F]F-FDG PET/CT between May 2020 and August 2021. [ 18 F]F-FAPI and [ 18 F]F-FDG uptakes were compared using the paired samples t test, and lesion numbers were compared using the Wilcoxon signed-rank test. Results Thirty-four LAD patients were evaluated. Patients showed high [ 18 F]F-FAPI uptake in primary lesions (SUVmax 12.54 ± 3.77). Both [ 18 F]F-FAPI and [ 18 F]F-FDG had 100% detection rates for primary tumors. However, [ 18 F]F-FAPI showed higher SUV max than [ 18 F]F-FDG in lesions of the lymph nodes, pleura, bones, and other tissues (all P  ≤ 0.05). Although the absolute uptake values of [ 18 F]F-FAPI in brain lesions were lower than those of [ 18 F]F-FDG (1.56 ± 2.19 vs.7.34 ± 3.54, P  < 0.0001), the tumor-to-background (T/B) ratios were significantly higher than those of [ 18 F]F-FDG (9.53 ± 12.07 vs.1.01 ± 0.49, P  < 0.0001). Generally, [ 18 F]F-FAPI PET/CT could visualize more total lesions than [ 18 F]F-FDG (554 vs.464, P  = 0.003), especially in lymph nodes (258 vs.229, P  = 0.039), the brain (34 vs.9, P  = 0.002), and pleura (56 vs.30, P  = 0.041). However, contrast-enhanced brain magnetic-resonance imaging (MRI) showed more brain lesions than [ 18 F]F-FAPI PET/CT (56 vs.34, P  = 0.002). Compared with the [ 18 F]F-FDG-based TNM stage, the [ 18 F]F-FAPI-based TNM stage was upgraded in six patients (17.6%). Conclusions [ 18 F]F-FAPI PET/CT showed a very high detection rate for primary LAD. In addition, 18 F-FAPI PET/CT demonstrated clearer tumor delineation and more lesions than [ 18 F]F-FDG PET/CT, especially in lymph nodes, the brain, and pleura. Therefore, [ 18 F]F-FAPI had an advantage over [ 18 F]F-FDG for primary staging of LAD. However, brain MRI could identify more and smaller lesions than [ 18 F]F-FAPI PET/CT.