Association of leukotrienes and prostaglandins with splenic 18F-FDG uptake in hepatobiliary cancer patients

Objective: In this study, we aimed to evaluate the relationship between lipid metabolites and diffuse splenic F-18-FDG uptake with the means of leukotriene (LT) and prostaglandin (PG). Subjects and methods: We enrolled 36 patients with hepatobiliary malignancies who underwent fluorine-18-fluorodeoxyuglucose (F-18-FDG) positron emission tomography/computed tomography (PET/CT) for staging workup. Patients were divided into two groups according to spleen to liver ratio (S/L ratio) of F-18-FDG uptake. Blood sample of each patient was collected on the day of conducting PET/CT scanning. Several types of LT and PG, including LTB4, LTC4, LTE4, PGD2, PGE2, and PGF2 alpha were measured from blood plasma samples from 36 patients using enzyme immunoassay (EIA kit, Cayman Chemical Co.). Results: White blood cell counts (P=0.0176) and C-reactive protein (P=0.0036) were higher in patients with splenic F-18-FDG uptake exceeding hepatic F-18-FDG uptake. Among the several types of PG and LT, PGD2 (P=0.0033) was higher in patients with hepatic F-18-FDG uptake exceeding splenic F-18-FDG uptake, however, LTC4 (P=0.0237) and LTE4 (P=0.0429) were higher in patients with splenic F-18-FDG uptake over hepatic uptake. Higher levels of LTC4 and lower levels of PGD2 are shown in patients with splenic F-18-FDG uptake. Conclusion: If the clinician incidentally finds splenic F-18-FDG uptake exceeding hepatic uptake, concurrent inflammation should be considered.