Evaluation of 18F-2-deoxy-2-fluoro-glucose positron emission tomography for gastric cancer screening in asymptomatic individuals undergoing endoscopy

Abstract

18 F-2-deoxy-2-fluoro-glucose Positron Emission Tomography (FDG-PET) has been recently proposed as a promising cancerscreening test. However, the validity of FDG-PET in cancer screening has not been evaluated. We investigated the sensitivity of FDG-PET compared with upper gastric endoscopy in gastric cancer screening for asymptomatic individuals. A total of 2861 consecutive subjects (1600 men and 1261 women) who were asymptomatic and who underwent both FDG-PET and upper gastrointestinal endoscopy between 1 February 2004 and 31 January 2005 were included in this study. Both endoscopists and a radiologist were unaware of the results of the other diagnostic tests. The FDG-PET images were examined using criteria determined by the pattern of FDG accumulation. Sensitivity and specificity of FDG-PET were calculated compared with endoscopic diagnosis as the gold standard. Among 2861 subjects enrolled in the study, there were 20 subjects with gastric cancer, of whom 18 were T1 in depth of cancer invasion. Positive FDG-PET results were obtained only in 2 of the 20 cancer subjects. The calculated sensitivity and specificity for overall gastric cancers were 10.0% (95% confidence interval (CI): 1.2 -31.7%) and 99.2% (95% CI: 98.8 -99.5%), respectively. 18 F-2-deoxy-2-fluoro-glucose Positron Emission Tomography was poorly sensitive for detection of gastric cancer in the early stages.

Gastric cancers with microsatellite instability exhibit high fluorodeoxyglucose uptake on positron emission tomography

“…Notably, in our study, 29 gastric cancers that were not detected on PET/CT imaging were all MSS gastric cancers. Although there are several studies that have shown different degrees of FDG uptake in primary gastric cancer on PET imaging [3,[11][12][13], this is the first study that shows the significance of MSI in detecting gastric cancers using PET/CT imaging.…”

“…For gastric cancers, FDG-PET imaging provides important additional information concerning the prognosis of recurrent cancer, including lymph node metastases, peritoneal carcinomatosis, distant metastasis, tumor response to treatment, and overall survival [3][4][5][6][7][8][9][10]. However, some subtypes of gastric cancer exhibit reduced FDG uptake [3,[11][12][13][14], which significantly limits the use of PET in gastric cancer.…”

Lymph nodes and gastric cancer

“…The sensitivity for LNs is improved when uptake of FDG is high by the primary tumor [14,15]. Specificity for both the primary tumor and metastatic LNs is consistently very high (90-100%) [15,20,23], which is better than the specificity of CT [14]. Staging accuracy, and hence decision-making, is improved when PET and CT are both utilized rather than either alone [14].…”

“…FDG PET sensitivity for gastric tumors is typically reported to be the same or poorer than CT (45-95% for PET), but depends greatly on the tumor stage (T1 poorer than T2-T4) [14,20], histological type (mucinous worse than non-mucinous) [14,15,21,22], and appears to be directly related to the expression of the glucose transporter-1 (GLUT-1) [22]. Hence, PET is not an appropriate screening tool [20]. Sensitivity for metastatic LNs in the context of gastric cancer is approximately 30-60%, and ranges from 8 to 88% when separated into locoregional and distant nodes.…”

Japanese Gastric Cancer Association Task Force for Research Promotion: clinical utility of 18F-fluoro-2-deoxyglucose positron emission tomography in gastric cancer. A systematic review of the literature

“…Of these, 11 were malignant tumors, including 3 gastric cancers, 2 small bowel cancers, and 6 colon cancers. Shoda et al [50] compared the sensitivity of PET with that of upper gastric endoscopy in gastric cancer screening for 2861 asymptomatic subjects. Positive PET results were obtained in only 2 of 20 (10%) patients with gastric cancer, including 18 T1 tumors.…”