Role of [18F]FAPI-04 in staging and therapeutic management of intrahepatic cholangiocarcinoma: prospective comparison with [18F]FDG PET/CT
Jiucen Liang, Shuqin Jiang, Jingjing Song, Danyang Chen, Shaojuan Weng, Shuyi Li, Hao Peng, Zhidong Liu, Jing Zhang, Yuanlin Chen, Songquan Rao, Haipeng Chen, Rusen Zhang, Hao Liu, Linqi Zhang
Abstract
Abstract Background Fluorine-18 fluorodeoxyglucose ([ 18 F]FDG) positron emission tomography/computed tomography (PET/CT) has some limitations in diagnosis of Intrahepatic cholangiocarcinoma (ICC). Materials and methods Patients with histologically confirmed ICC who underwent both [ 18 F]FDG and 18 F-labeled fibroblast-activation protein inhibitors ([ 18 F]FAPI)-04 PET/CT were prospectively analyzed. The maximum standard uptake value (SUV max ), tumor-to-background ratio (TBR), metabolic tumor volume (MTV), total lesion glycolysis (TLG), [ 18 F]FAPI–avid tumor volume (FTV), total lesion fibroblast activation protein expression (TLF) were compared between the two modalities by paired Wilcoxon signed-rank test and Mann–Whitney U test, and McNemar’s test was used to assess the diagnostic accuracy between the two techniques. Results In total, 23 patients with 389 lesions were included. Compared to [ 18 F]FDG, [ 18 F]F-FAPI-04 PET/CT demonstrated a higher detection rate for intrahepatic lesions (86.3% vs. 78.2% P = 0.040), lymph node metastases (85.2% vs. 68.2%, P = 0.007), peritoneal metastases (100% vs. 93.8%), and bone metastases (100% vs. 70.5%, P < 0.001). [ 18 F]FAPI-04 PET showed higher SUV max , TBR and greater tumor burden values than [ 18 F]FDG PET in non-cholangitis intrahepatic lesions (SUV max : 8.7 vs. 6.4, P < 0.001; TBR: 8.0 vs. 3.5, P < 0.001; FTV vs. MTV: 41.3 vs. 12.4, P < 0.001; TLF vs. TLG: 223.5 vs. 57.0, P < 0.001), lymph node metastases (SUV max : 6.5 vs. 5.5, P = 0.042; TBR: 5.4 vs. 3.9, P < 0.001; FTV vs. MTV: 2.0 vs. 1.5, P = 0.026; TLF vs. TLG: 9.0 vs. 7.8 P = 0.024), and bone metastases (SUV max : 9.7 vs. 5.25, P < 0.001; TBR: 10.8 vs. 3.0, P < 0.001; TLF vs. TLG: 9.8 vs. 4.2, P < 0.001). However, [ 18 F]FDG showed higher radiotracer uptake (SUV max : 14.7 vs. 8.4, P < 0.001; TBR: 7.4 vs. 2.8, P < 0.001) than [ 18 F]FAPI-04 PET/CT for 6 patients with obstructive cholangitis. [ 18 F]FAPI-04 PET/CT yielded a change in planned therapy in 6 of 23 (26.1%) patients compared with [ 18 F]FDG. Conclusions [ 18 F]FAPI-04 PET/CT had higher detection rate and radiotracer uptake than [ 18 F]FDG PET/CT in intrahepatic lesions, lymph node metastases, and distant metastases, especially in bone. Therefore, [ 18 F]FAPI-04 PET/CT may be a promising technique for diagnosis and staging of ICC. Trial registration Clinical Trials, NCT05485792. Registered 1 August 2022, retrospectively registered, https//clinicaltrials.gov/study/NCT05485792?cond=NCT05485792&rank=1.