The role of 68Ga-FAPI PET/CT imaging in gynecological cancers: an integrative review

Clinical staging of gynecological cancers traditionally employs computed tomography (CT) scan or 18fluorine-deoxyglucose PET/CT (18F-FDG PET/CT), which have limited sensitivity, especially for early-stage ovarian cancer, borderline tumors, tumors with cystic/mucinous components, and those with low metabolic activity. Fibroblast activation protein inhibitor (FAPI) targets cancer-associated fibroblasts in tumor stroma independent of metabolic activity, providing favorable tumor-to-background contrast when used with PET imaging. We conducted an integrative review of FAPI PET/CT use in gynecological cancers for staging, treatment response assessment, and recurrence detection. Database searches yielded 205 documents, with 23 studies meeting inclusion criteria (12 original research articles, 7 case reports, 4 reviews). 68Ga-FAPI PET/CT image was reported to be superior to 18F-FDG PET/CT in differentiating high-grade from lower-grade ovarian cancer, detection of nodal, peritoneal, and pleural disease, as well as early relapses. 68Ga-FAPI PET/CT showed enhanced detection of lymph node metastasis in newly diagnosed cervical cancer. However, its utility in endometrial cancer is limited by physiological uptake in normal uterine tissue. 68Ga-FAPI PET/CT shows promising results for diagnosis and staging of ovarian and cervical cancers. Further research is warranted as this modality has potential to modify treatment approaches by improving detection capabilities beyond conventional imaging techniques, particularly for tumors with challenging characteristics that limit current diagnostic methods.