Abstract
Introduction Early and precise diagnosis and staging of gastric cancer are important for its treatment and management. However, the low sensitivity of 18F-fluorodeoxyglucose (18F-FDG) for gastric cancer diagnosis limits its application. Currently, the tracer 68Ga-FAPI, which targets fibroblast activation protein (FAP), is widely used to diagnose various cancers. However, the diagnostic value of 68Ga-FAPI in gastric cancer is still unclear. In this study, we aimed to investigate the potential advantage of 68Ga-FAPI-04 over 18F-FDG in the evaluation of gastric cancer.Methods: Thirty-eight patients with gastric cancer (31 with adenocarcinoma and 7 with signet ring cell carcinoma) were recruited for this study. All of the participants underwent 68Ga-FAPI-04 and 18F-FDG imaging by positron emission tomography (PET)/computed tomography (CT) or PET/magnetic resonance (MR). The results were interpreted by two experienced nuclear medicine physicians, and the maximum standardized uptake value (SUVmax) was calculated.Results: For the detection of primary gastric cancer, the sensitivities of 68Ga-FAPI-04 PET and 18F-FDG PET were 100% (38/38) and 81.6% (31/38), respectively. Four cases of adenocarcinoma and three cases of signet ring cell carcinoma were missed by 18F-FDG PET. The SUVmax of 68Ga-FAPI-04 in tumors greater than 4 cm (11.0 ± 4.5) was higher than tumors less than 4 cm (4.5 ± 3.2) (P = 0.0015). The SUVmax of 68Ga-FAPI-04 was higher in T2-4 tumors (9.7 ± 4.4) than in T1 tumors (3.1 ± 1.5) (P = 0.0002). For the detection of metastatic lesions, the sensitivities of 68Ga-FAPI-04 PET and 18F-FDG PET in 10 patients with regional lymph node metastasis and distant metastasis were 6/10 and 5/10, respectively.Conclusion: Compared to 18F-FDG PET, 68Ga-FAPI-04 PET had superior potential in detecting primary gastric cancers and metastatic lymph nodes, 68Ga-FAPI-04 PET also had a better performance on small gastric cancer detection. 68Ga-FAPI-04 PET could provide better performance for gastric cancer diagnosis and staging.
CD44v6, MMP-7 and nuclear Cdx2 are significant biomarkers for prediction of lymph node metastasis in primary gastric cancer
