Position emission tomography with or without computed tomography in the primary staging of Hodgkin's lymphoma

In order to receive the most appropriate therapy, patients with Hodgkin's lymphoma (HL) must be accurately stratified into different prognostic staging groups. Computed tomography (CT) plays a pivotal role in the conventional staging. The aim of the present study was to investigate the value of positron emission tomography using 2-[18F]fluoro-2-deoxy-D-glucose (FDG-PET) and combined FDG-PET/CT for the staging of HL patients, and the impact on the choice of treatment.

Ninety-nine consecutive, prospectively included patients had FDG-PET and CT in their staging work-up. Sixty-one of the 99 patients had combined FDG-PET/CT. A standard of reference for each nodal region and organ was determined using all available information including scan results, histology and a minimum of one year's clinical follow-up data. The lack of a satisfactory diagnostic gold standard limits the reliability of accuracy calculations.

FDG-PET would have upstaged 19% of patients and downstaged 5% of patients, leading to a different treatment in 9% of patients. For FDG-PET/CT, the corresponding figures are 17%, 5%, and 7%. In nodal regions, the sensitivity of FDG-PET and FDG-PET/CT seemed higher than that of CT (92% and 92% vs. 83%). FDG-PET identified more false positive nodal sites than did CT and FDG-PET/CT (1.6% vs 0.7% and 0.5%). FDG-PET and FDG-PET/CT were highly sensitive for evaluating organs (86% and 73%) while CT detected 37% of involved organs.

FDG-PET and FDG-PET/CT have a substantial potential impact on staging and choice of treatment and the methods tend to upstage rather than downstage patients. FDG-PET and FDG-PET/CT seem to have a higher diagnostic accuracy than CT in the staging of HL. However, care should be taken so patients with an excellent prognosis and at risk of over-treatment do not receive more intensive treatment because of these staging methods.