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

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 (SUV_max), 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 SUV_max 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 SUV_max 10.4, range 2.0–17.9). Thirty-seven of thirty-nine patients with baseline SUV_max < 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 SUV_max values in HD and NHL. A heterogeneous outcome was noted in 25 patients with a SUV_max ≥ 7.4 and ≤ 12.9 at diagnosis, with 16 patients experiencing disease progression or relapse and nine patients extended remission. The five patients with SUV_max > 12.9 showed disease progression at follow-up. Semiquantitative measurement of glucose metabolism (SUV_max) by ¹⁸F-FDG PET at diagnosis is a predictor of outcome of patients with malignant lymphoma.