The role of PET/CT in the evaluation of gastric cancer recurrence

PurposeF-18-fluorodeoxyglucose positron emission tomography/computed tomography(F-18 FDG PET/CT) has been widely used for staging, re-staging and for monitoring therapy-induced changes and response to therapy in patients with various types of cancer, but its utilization for gastric cancer has been limited. This study aimed to assess the diagnostic performence of F-18 FDG PET/CT for detecting recurrence in gastric cancer patients with radiologic or clinical suspension of recurrence.Materials and MethodsWe performed a retrospective review of 130 consecutive patients who underwent PET/CT scans for post treatment surveillance of gastric cancer between January 2008 and March 2012. The number and site of positive FDG uptakes were analyzed and were correlated with the final diagnosis by calculating the diagnostic values. We evaluated the diagnostic accuracy of PET/CT for detecting the recurrence in the patients with histopathologic types of signet ring cell carcinoma (SRC) and mucinous adenocarcinoma. Cut-off SUVmax values in differentiating benign lesions from recurrence in different organs and the changes in the clinical management of patients according to the results of PET/CT were also evaluated.ResultsOf all 130 patients, 91 patients were confirmed to have true recurrence. The sensitivity, specificity, positive predictive value, negative predictive value and the dignostic accuracy of PET/CT for diagnosing true recurrence on a per-person basis were 91.2 %, 61.5 %, 84.6 %, 75.0 % and 82.3 % respectively. In the subgroup with SRC and mucinous adenocarinoma differentiation of the primary tumor, there was no statistically significant difference in terms of diagnostic accuracy of PET/CT on a per-person basis. PET/CT had also detected second primary cancer in two patients and the PET/CT results changed the patients? management in 20(15 %)cases.ConclusionFDG PET/CT was highly effective in discriminating true recurrence in patients with gastric cancer and had important impacts on clinical decisions in a considerable portion of patients.KeywordsPositron-Emission Tomography and Computed Tomography, stomach neoplasms, recurrence