Prognostic Value of 18 F-FDG PET/CT Metabolic Parameters in Splenic Marginal Zone Lymphoma.

INTRODUCTION: Splenic marginal zone lymphoma (SMZL) is an indolent non-Hodgkin lymphoma usually with a good prognosis, but no clear metabolic behavior at fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). The aim of our analysis was to investigate the prognostic role of baseline 18F-FDG PET/CT parameters in SMZL.

MATERIALS AND METHODS: We retrospectively included 42 patients who received 18F-FDG-PET/CT before any treatments, and PET images were evaluated visually and semi-quantitatively by measuring lesion to liver (L-L) maximum standardized uptake volume (SUVmax) ratio (L-L SUV R), lesion to blood-pool SUVmax ratio (L-BP SUV R), metabolic tumor volume, and total lesion glycolysis. Progression-free (PFS) and overall survival (OS) curves were plotted according to the Kaplan-Meier method.

RESULTS: In all patients, an increased splenic FDG uptake (higher than the background) was identified, showing the presence of diffuse spleen uptake in 35 patients and focal uptake in the remaining 7 patients. At a median follow-up of 51 months, relapse or progression of disease occurred in 23 patients with an average time of 38.1 months from the baseline 18F-FDG PET/CT, and death occurred in 4 patients with an average time of 26.8 months. The estimated 2-year PFS and OS rates were 78% and 90%, respectively, whereas 5-year PFS and OS rates were 63% and 82%, respectively. At multivariate analysis, only L-L SUV R and L-BP SUV R were independent prognostic factors for PFS. In addition, no significant association was discovered for OS, considering all features.

CONCLUSIONS: L-L SUV R and L-BP SUV R were independently correlated with PFS.