Comparison of (68)Ga-FAPI-04 and fluorine-18-fluorodeoxyglucose PET/computed tomography in the detection of ovarian malignancies

Currently, fluorine-18-fluorodeoxyglucose ((18)F-FDG) is the most frequently used diagnostical radiotracer for PET/computed tomography (PET/CT) in ovarian malignancies. However, (18)F-FDG has some limitations. The fibroblast activation protein inhibitor (FAPI) previously demonstrated highly promising results in studies on various tumor entities and (68)Ga-labeled FAPI presents a promising alternative to (18)F-FDG. This study aimed to compare the performance of (68)Ga-FAPI and (18)F-FDG PET/CT for imaging of ovarian malignancies. METHODS: A total of 27 patients were included in this retrospective study conducted at the Affiliated Hospital of Southwest Medical University between June 2020 and February 2022. The (18)F-FDG and (68)Ga-FAPI uptakes of tumors, lymph nodes, and distant metastases were quantified using the maximum standardized uptake values, and the tumor-to-background ratios were also evaluated and calculated by using the Wilcoxon signed-rank test. RESULTS: Twenty-one patients with suspected (n = 11) and previously treated ovarian malignancies (n = 10) were in statistical analysis finally. For detecting tumors, (68)Ga-FAPI PET/CT was more sensitive than (18)F-FDG PET/CT [14 of 14 (100%) vs. 11 of 14 (78%)], lymph node metastases [75 of 75 (100%) vs. 60 of 75 (80%)] and superior to (18)F-FDG PET/CT in terms of the peritoneal and pleural metastases [9 of 9 (100%) vs. 5 of 9 (56%)]. For four of the newly diagnosed patients (n = 11), (68)Ga-FAPI PET/CT upstaged the clinical stage compared to (18)F-FDG PET/CT. CONCLUSION: (68)Ga-FAPI PET/CT has superior potential in the detection of ovarian cancers, especially in peritoneal carcinomatosis. (68)Ga-FAPI PET/CT may be a promising supplement for staging and follow-up of ovarian malignancies.