68Ga-FAPI-04 Versus 18F-FDG PET/CT in the Detection of Hepatocellular Carcinoma

Abstract

BackgroundFibroblast activation protein (FAP) is commonly expressed in activated stromal fibroblasts in various epithelial tumours. Recently, 68Ga-FAPI-04 has been used for tumour imaging in positron emission tomography/computed tomography (PET/CT). This study aimed to compare the diagnostic performances of 68Ga-FAPI-04 PET/CT and 18F-FDG PET/CT in hepatocellular carcinoma (HCC), and to assess factors associated with 68Ga-FAPI-04 uptake in HCC.Materials and MethodsTwenty-nine patients with suspiciously HCC who received both 18F-FDG and 68Ga-FAPI-04 PET/CT were included in this retrospective study. The results were interpreted by two experienced nuclear medicine physicians independently. The maximum and mean standardized uptake values (SUVmax and SUVmean) were measured in the lesions and liver background, respectively. The tumour-to-background ratio (TBR) was then calculated as lesion’s SUVmax divided by background SUVmean.ResultsA total of 35 intrahepatic lesions in 25 patients with HCC were finally involved in the statistical analysis. 68Ga-FAPI-04 PET/CT showed a higher sensitivity than 18F-FDG PET/CT in detecting intrahepatic HCC lesions (85.7% vs. 57.1%, P = 0.002), including in small (≤ 2 cm in diameter; 68.8% vs. 18.8%, P = 0.008) and well- or moderately-differentiated (83.3% vs. 33.3%, P = 0.031) tumors. SUVmax was comparable between 68Ga-FAPI-04 and 18F-FDG (6.96 ± 5.01 vs. 5.89 ± 3.38, P > 0.05), but the TBR was significantly higher in the 68Ga-FAPI-04 group compared with the 18F-FDG group (11.90 ± 8.35 vs. 3.14 ± 1.59, P < 0.001). SUVmax and the TBR in 68Ga-FAPI-04 positive lesions were associated with tumour size (both P < 0.05), but not the remaining clinical and pathological features (all P > 0.05).Conclusions68Ga-FAPI-04 PET/CT is more sensitive than 18F-FDG PET/CT in detecting HCC lesions, and 68Ga-FAPI-04 uptake is correlated mainly with tumour size.

Head-to-Head Comparison of Fibroblast Activation Protein Inhibitors (FAPI) Radiotracers versus [18F]F-FDG in Oncology: A Systematic Review

“…No additional studies were found screening the references of the selected articles. Finally, 26 articles (925 patients) including data on the comparison between radiolabeled FAPI and [ 18 F]F-FDG as PET radiotracers in oncology were included in the systematic review [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. The characteristics of the studies selected for the systematic review are presented in Table 1 , Table 2 , Table 3 .…”

“…Through the comprehensive computer literature search, 26 full-text articles including data on the head-to-head comparison of radiolabeled FAPI and [ 18 F]F-FDG in cancer patients were selected ( Table 1 ) [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. All the selected articles were published in the last two years.…”

“…Regarding the normal tissue biodistribution of radiolabeled FAPI in comparison to [ 18 F]F-FDG, all the included studies showed a lower radiolabeled FAPI uptake in the normal brain, liver, and oral mucosa, compared to [ 18 F]F-FDG [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”

“…Overall, taking into account the radiotracer uptake and TBR values, compared to [ 18 F]F-FDG PET, an equal or higher detection of primary tumors and/or metastatic lesions was usually demonstrated by using radiolabeled FAPI PET [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. In particular, the cancer entities with better detection rate of tumor lesions by using radiolabeled FAPI PET compared to [ 18 F]F-FDG PET were gastrointestinal tumors, liver tumors, breast cancer and nasopharyngeal carcinoma.…”

Methylosystem for Cancer Sieging Strategy

“…A recent study indicated that fibroblast activation protein (FAP), which promotes tumor growth and progression, is overexpressed in the CAFs of many human epithelial cancers, including pancreatic cancer, and is an attractive target for marking by 64Cu-and 225Ac-labeled FAP inhibitor FAPI-04, which have been used as theranostics for treating FAP-expressing pancreatic cancer, as shown in a proof-of-concept study [73]. In a study on hepatocellular carcinoma, the usefulness of 68Ga-FAPI-04 positron emission tomography/computed tomography (PET/CT) was demonstrated, and 68Ga-FAPI-04 PET/CT was found to be more sensitive than 18F-FDG PET/CT in detecting hepatocellular carcinoma lesions, as 68Ga-FAPI-04 uptake is primarily correlated with tumor size, suggesting clinical benefits [74]. Another study reported that FAP-specific PET/CT imaging in fibrotic interstitial lung diseases and lung cancer provided potential clinical value for the monitoring and therapeutic evaluation of fibrotic interstitial lung diseases and suggested that these areas be investigated in future studies [75].…”