Gallium 68-labeled FAPI-PET promising for biliary tract cancer detection: Study
China: Gallium 68-labeled fibroblast-activation protein inhibitor (FAPI)-PET imaging is superior to current methods for more accurate staging of biliary tract cancer (BTC), thereby improving treatment decision making, states a recent study in Radiology.
In previous studies, Gallium 68–labeled fibroblast-activation protein inhibitor (68Ga-FAPI) is imaging for tumor detection that represents a promising alternative to fluorine 18 fluorodeoxyglucose (18F-FDG). Lianjun Lan, a radiologist at the Affiliated Hospital of Southwest Medical University in Luzhou, and colleagues, therefore, aimed to compare the potential efficacy of 68Ga-FAPI PET/CT with that of 18F-FDG PET/CT for detecting primary tumor and nodal and distant metastases in biliary tract cancer and to explore the impact (tumor staging) of 68Ga-FAPI compared with 18F-FDG on clinical management of BTC in a single-center prospective clinical study.
The study was performed at the Affiliated Hospital of Southwest Medical University between June 2020 and June 2021. Patients with BTC underwent both 68Ga-FAPI and 18F-FDG PET/CT. Histopathologic examination, morphologic imaging, and/or follow-up imaging served as the reference standard.
The paired-sample t-test was used to compare the maximum standardized uptake value (SUVmax) of the primary tumor and nodal and distant metastases between 18F-FDG and 68Ga-FAPI PET/CT.
Key findings of the study include:
· Eighteen participants with primary or recurrent BTC were evaluated (mean age, 61 years ± 10 [SD]).
· The sensitivity of 68Ga-FAPI PET/CT was higher than that of 18F-FDG PET/CT for detecting primary tumors (16 of 16 [100%] vs 13 of 16 [81%]), nodal metastases (41 of 42 [98%] vs 35 of 42 [83%]), and distant metastases (99 of 99 [100%] vs 78 of 99 [79%]).
· 68Ga-FAPI PET/CT resulted in new oncologic findings in 10 of 18 participants and upgraded tumor staging or restaging in five of 18 participants compared with 18F-FDG PET/CT.
· 68Ga-FAPI PET/CT demonstrated higher sensitivity than 18F-FDG PET/CT in inflammatory processes secondary to tumor-related obstruction (seven of eight [88%] vs one of eight [13%]).
· 68Ga-FAPI showed lower average SUVmax in inflammatory processes than in oncologic lesions (4.9 ± 2.6 vs 10.0 ± 4.6, respectively).
To conclude, 68Ga-FAPI PET/CT for tumor staging showed potential for more accurate staging of biliary tract cancer, thereby improving treatment decision making.
Reference:
Lan L, Zhang S, Xu T, Liu H, Wang W, Feng Y, Wang L, Chen Y, Qiu L. Prospective Comparison of 68Ga-FAPI versus 18F-FDG PET/CT for Tumor Staging in Biliary Tract Cancers. Radiology. 2022 May 17:213118. doi: 10.1148/radiol.213118. Epub ahead of print. PMID: 35579524.
