18F-fluorodeoxyglucose positron emission tomography-computed tomography scan after gastric endoscopy in those who present with non-specific symptoms, is it necessary or not?

Background and Aims: Retrospectively analyze the sensitivity of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) in the diagnosis of gastric malignancy compared with gastric endoscopy in persons with nonspecific symptoms and evaluate the necessity of 18F-FDG PET-CT scan before surgery. Materials and Methods: A total of 53 patients with gastric malignancy proven by surgery and pathology were enrolled in the study. All the patients underwent gastric endoscopy and PET-CT scan before surgery. And the PET-CT images were interpreted by the observers who were blinded to the results of the gastric endoscopy. The sensitivity of gastric endoscopy, 18F-FDG PET-CT, and serum tumor markers in the diagnosis of gastric malignancy were calculated ultimately. Results: Of 53 gastric malignancy patients, five cases were proven to be false-negative detected by gastric endoscopy, and the sensitivity of which was 90.57%. The sensitivity of PET scan alone was 86.79%, which was observed no significant difference to that of gastric endoscopy diagnosis, P = 0.54. While all of the patients had been detected positive on PET-CT images, the sensitivity of which was significantly higher than that of the gastric endoscopy diagnosis or that of the serum tumor markers, P < 0.001. And the FDG uptake was positively correlated with the depth of the cancer invasion into the gastric wall (P < 0.0001) and the degree of lymph nodes infiltration (P = 0.02). It also various from different differentiation degree significantly, P = 0.04. Conclusions: 18F-fluorodeoxyglucose PET-CT could detect gastric carcinoma in persons with nonspecific symptoms which showed negative in gastric endoscopy. And it is necessary to be aware of the possibility of gastric malignancy when the result of PET-CT scan is positive.