Prognostic significance of the standardized uptake value of pre-therapeutic 18F-FDG PET in patients with malignant lymphoma

Abstract

Metabolic imaging with F-18-fluorodeoxyglucose (18F-FDG) positron-emission tomography (PET) is widely used for staging and treatment evaluation of malignant lymphoma. To date, only a few studies have indicated that lower glucose metabolism measured by 18F-FDG PET before or early in the course of treatment of malignant lymphoma is associated with a favorable outcome. The aim of this study was to assess the prognostic capability of the 18F-FDG PET maximum standardized uptake value (SUVmax), a semiquantitative measurement of glucose metabolism, at the time of diagnosis of malignant lymphoma. We retrospectively analyzed data from 69 patients (median age: 61 and range 23-80) with malignant lymphoma (22 patients with Hodgkin's disease [HD] and 47 patients with Non-Hodgkin's lymphoma [NHL]) who had not received treatment before 18F-FDG PET imaging. Metabolic remission according to PET results was observed after chemotherapy in 50 patients (72.5%), while progressive disease or relapse was diagnosed in 19 patients (27.5%). Clinical follow-up revealed relapse in 4/50 patients with prior metabolic remission. A significantly lower (P<0.01) baseline SUVmax level (median: 4.6 and range 1.5-12.9) was found in patients with subsequent metabolic and clinical response than in those with progressive or relapsing disease (median SUVmax 10.4, range 2.0-17.9). Thirty-seven of thirty-nine patients with baseline SUVmax<7.4 achieved long-lasting remission after completion of chemotherapy (median follow-up: 28 months, range 4-112 months). Within this group with favorable outcome, there were no significant differences between SUVmax values in HD and NHL. A heterogeneous outcome was noted in 25 patients with a SUVmax≥7.4 and ≤12.9 at diagnosis, with 16 patients experiencing disease progression or relapse and nine patients extended remission. The five patients with SUVmax>12.9 showed disease progression at follow-up. Semiquantitative measurement of glucose metabolism (SUVmax) by 18F-FDG PET at diagnosis is a predictor of outcome of patients with malignant lymphoma.