Role of 18F-FDG PETCT as a predictor of eradication of Helicobacter pylori in the patients with early-stage gastric B cell lymphoma.

1684 Background: Eradication of Helicobacter pylori has been reported to be effective in the treatment of early stage gastric B-cell lymphoma as well as MALT lymphoma. In some cases, eradication alone results in CR, while in others, residual or enlarged lesions may lead to subsequent chemotherapy. In this study, we investigated whether a PET/CT prior to the treatment is useful in differentiating responder and non-responder to the eradication therapy. Methods: Twenty-one patients with a diagnosis of histologically proven early-stage (Lugano-stage 1) gastric B-cell lymphoma were included in the study. There were 8 males and 13 females (mean age: 58.7 ± 14.4 years; range: 46 to 71 years). All patients underwent 18F-FDG PET/CT prior to the treatment. PET images were analyzed semiquantitatively using SUVmax, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) and compared them between the responder and non-responder groups. Results: As a result of eradication of Helicobacter pylori, 13 out of 21 patients achieved CR with eradication alone (responder), but 8 patients had residual disease or progression and required subsequent chemotherapy (non-responder). SUVmax, MTV and TLG were (14.6±4.7, 63.6±34.3 and 341.2±102.3) in responder group and (6.8±3.5, 17.0±15.3 and 81.2±72.3) in non-responder group respectively. There was statistically significant difference in MTV and TLG between two groups (p<0.05). As for prognostic performance, sensitivity, specificity, accuracy and AUC were (75%, 77%, 76% and 0.86:cut-off=45.2) with MTV and (88%, 69%, 76% and 0.75: cut-off=40.7) with TLG respectively. Conclusions: Semiquantitative volumetrics analysis of FDG-PET/CT may be useful for the prediction of treatment outcome of eradication of Helicobacter pylori for gastric B-cell lymphoma.