FDG-PET/CT predicts outcome in patients with aggressive non-Hodgkin's lymphoma and Hodgkin's disease

Early therapy response assessment with metabolic imaging is potentially useful to determine prognosis in aggressive lymphoma and, thus, can guide first-line therapy. Forty-eight patients with aggressive lymphoma [24 Hodgkin's disease (HD); 24 non-Hodgkin's lymphoma (NHL)] underwent fluoro-deoxyglucose positron emission tomography (FDG-PET) before chemotherapy (PET1) and at mid-treatment (PET2). Therapeutic response was evaluated using conventional methods at mid-treatment. PET2 results were related to event-free survival (EFS) and overall survival (OS) using Kaplan-Meier analyses. PET1 was positive in all patients. PET2 was negative in 38 patients (18 NHL-20 HD) and positive in 10 (6 NHL-4 HD). Of the PET-negative patients, 61 and 65% achieved complete remission, and only 50 and 25% of PET-positive patients, respectively, for NHL and HD, achieved complete remission. Significant associations were found between PET2 and EFS (p=0.0006) and OS (p=0.04) for NHL, and EFS (p < 0.0001) for HD (but not for OS, because no HD patient died). FDG-PET at mid-treatment can predict the outcome of patients with aggressive lymphoma and should be a useful tool to modify an ineffective therapy.