Impact of 68Ga-FAPI-04 positron emission tomography/computed tomography (PET/CT) on staging and treatment in patients with gastric cancer

Background 68Ga-labeled fibroblast activation protein inhibitor (FAPI) positron emission tomography (PET)/computed tomography (CT) has been shown to be advantageous in the detection of primary and metastatic lesions in many types of tumors, especially gastric cancer. However, there is a paucity of data on the value of 68Ga-FAPI-04 PET/CT for initial staging, recurrence detection after surgery and management of gastric cancer patients.Methods114 patients with gastric cancer who underwent contrast-enhanced CT and 68Ga-FAPI-04 PET/CT within one months were included. Two nuclear medicine physicians and a radiologist independently reviewed the imaging. TNM staging outcomes and subsequent treatment decisions were compared between contrast-enhanced CT and 68Ga-FAPI-04 PET/CT.Results84 patients underwent 68Ga-FAPI-04 PET/CT scans for initial staging, comprising 12 with stage II, 44 with stage III, and 28 with stage IV as per CT staging. Furthermore, 30 postoperative patients underwent PET-CT scanning in the presence of clinical symptoms, abnormal laboratory tests, and ambiguous CT findings. PET-CT revealed 29 newly metastatic lesions, with distant lymph nodes (12 occurrences) and peritoneal lesions (11 occurrences) being the most frequently observed. 68Ga-FAPI-04 PET/CT revised staging in 22/114 patients (19.3%). Among those, downstaging was recorded in 4/22 cases (18.2%) and upstaging in the remaining 18/22 (81.8%) patients. Overall, the findings of 68Ga-FAPI-04 PET/CT led to a change in clinical management in 15/114 patients (13.1%), including 12 instances of major and 3 instances of minor therapeutic changes. In 30 postoperative patients, 8 cases (26.3%) had recurrent metastasis, leading to 13.3% management change. Among 84 initial staging patients, 14 cases (16.7%) had staging change, resulting in 13.1% management change.Conclusions68Ga-FAPI-04 PET/CT proved to be a valuable tool for precise staging of gastric cancer patients. 68Ga-FAPI-04 PET/CT promises to improve conventional radiologic imaging methods for gastric cancer staging.Legal entity responsible for the studyThe authors.FundingHas not received any funding.DisclosureAll authors have declared no conflicts of interest.