18F-fluorodeoxyglucose positron emission tomography to evaluate recurrent gastric cancer: A systematic review and meta-analysis

Background and Aim: We aimed to explore the role of the diagnostic accuracy of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in detecting recurrent gastric cancer through a systematic review and meta-analysis. Methods: The MEDLINE, EMBASE, Cancerlit, and Cochrane Library database, from January 2001 to July 2011, were searched for studies evaluating the diagnostic performance of 18F-FDG PET in detecting recurrent gastric cancer. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic curves. We also compared the performance of 18F-FDG PET with computed tomography (CT) by analyzing studies that had also used these diagnostic methods on the same patients. Results: Across nine studies (526 patients), the overall sensitivity of 18F-FDG PET was 0.78 (95% confidence interval [ CI]: 0.68-0.86), and the overall specificity was 0.82 (95% CI: 0.76-0.87). Overall, LR+ was 3.52 (95% CI: 2.68-4.63) and LR-was 0.32 (95% CI: 0.22-0.46). In studies in which both 18F-FDG PET and other diagnostic tests were performed, the sensitivity and specificity of 18F-FDG PET were 0.72 (95% CI: 0.62-0.80) and 0.84 (95% CI: 0.77-0.90), respectively; of contrast CT, they were 0.74 (95% CI: 0.64-0.83) and 0.85 (95% CI: 0.78-0.90), respectively; and of combined PET and CT, they were 0.75 (95% CI: 0.67-0.82) and 0.85 (95% CI 0.79-0.90), respectively. Study sensitivity was not correlated with the prevalence of recurrent gastric cancer. Conclusion: 18F-FDG PET has good diagnostic performance in the overall evaluation of recurrent gastric cancer, but still has some limited performance compared with contrast CT. 18F-FDG PET combined with CT might improve the diagnostic performance in detecting recurrent gastric cancer.