Primary gastric lymphoma: utility of 18F-fluorodeoxyglucose positron emission tomography-computed tomography for detecting relapse after treatment.

The purpose of this study was to evaluate the role of 18F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography-computed tomography (PET-CT) in detecting relapse in patients with primary gastric lymphoma (PGL) post-treatment. Data of 39 previously treated patients with PGL (age: 50.3 ± 13.8 years; male: 24) who underwent 71 (18)F-FDG PET-CT studies for suspected relapse (n = 53) or routine follow-up (n = 18) were retrospectively evaluated. PET-CT images were evaluated both qualitatively and quantitatively (standardized uptake value [SUVmax]). A combination of clinical/imaging follow-up, endoscopy and/or histopathology was taken as the reference standard. The per patient based sensitivity of PET-CT was 96%, specificity 91% and accuracy 93%. The lymph node was the commonest site of relapse on PET-CT. Mean lesion SUVmax was 5.9 ± 3.1 (2.3-13.6). Accuracy was similar in suspected relapse and routine follow-up groups (90.5% vs. 100%; p = 0.409). Based on the data, (18)F-FDG PET-CT appears to be highly accurate for the detection of relapse in patients with PGL post-treatment.