Positron emission tomography with 2-[18F]-Fluoro-2-Deoxy-D-Glucose for initial staging of hodgkin lymphoma: a single center experience in Brazil

BACKGROUND: 2-[18F]-Fluoro-2-Deoxy-D-Glucose (FDG-PET) is a well established functional imaging modality for the initial staging of Hodgkin lymphoma (HL) in patients from Western Europe and North America. The reliability of FDG-PET in populations of different ethnic groups is unclear, as all investigations published to date have come from developed countries. PURPOSE: The aim of the present study was to investigate the effectiveness of FDG-PET in the initial staging of HL patients in a Brazilian population. METHODS: Eighty-two patients with newly diagnosed HL were prospectively included in the study. All patients were staged with both conventional clinical staging (CCS) methods, including computed tomography (CT) and whole-body FDG-PET methods. A standard of reference for the nodal regions and the extranodal organs was determined using all available information, including the CCS methods, FDG-PET, the diagnostic histology and the follow-up examinations. The results of the CCS were then compared to the FDG-PET results. RESULTS: The sensitivity of FDG-PET was higher for nodal staging than that of CT (87.8% vs. 61.6%, respectively). FDG-PET was also more sensitive than CT in regard to evaluating the extranodal organs for lymphomatous involvement (96.2% vs. 40.0%, respectively). FDG-PET detected all 16 patients who were characterized by a positive bone marrow biopsy and identified an additional 4 patients with bone marrow disease. The incorporation of FDG-PET coupled with CCS in the staging procedure upstaged 20% (17/82) of the patients and downstaged 11% (9/82) of the patients. As a result of these changes in staging, 15% (13/82) of the patients would have received a different therapeutic regimen. CONCLUSIONS: The FDG-PET method is superior to CT for the detection of nodal and extra-nodal HL. The observation that the FDG-PET method upstaged the disease was the most common result (20% of patients) brought about by the addition of PET to the staging algorithm, even in a population of patients with a high incidence of advanced disease. However, changes in stages based on FDG-PET results should be confirmed by biopsy