Utilization of 18F-FDG PET/CT as a staging tool in patients with newly diagnosed lymphoma

The aim of this study was to investigate the role of 2-fluorine-18-fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) in the initial staging and prediction of bone marrow involvement in patients with newly diagnosed lymphoma. A total of 185 patients with newly diagnosed lymphoma were enrolled. All patients received PET/CT and bone marrow biopsy as part of a staging work-up. At the initial staging, 17 patients (9.2%) with occult nodal or extranodal lesions were upstaged after a review of the PET/CT studies. PET/CT was found to be useful in the differentiation of aggressive lymphoma subtypes from the indolent subtype based on higher standardized uptake value (SUV) (16.67 vs. 7.98, p < 0.001). The results of bone marrow biopsy and PET/CT in the detection of bone marrow involvement were concordant in 152 patients (82.1%); positive concordance was observed in 21 patients, and negative concordance was observed in 131 patients. A high concordance rate was found between aggressive B cell lymphoma and Hodgkin's lymphoma (88.1% and 93.8%, respectively). High negative predictive values (NPVs) for excluding bone marrow involvement were observed in aggressive B-cell lymphoma (93.2%) and Hodgkin's lymphoma (100%). Diffuse bone marrow FDG uptake accurately predicted bone marrow in aggressive B-cell lymphoma with a positive predictive value (PPV) of 100%. The concordance rate was lower in indolent B-cell lymphoma (66.0%). In conclusion, PET/CT resulted in the upstaging of patients with occult extranodal or nodal lesions. A high SUV level can predict aggressive subtype of lymphoma and detect aggressive components in indolent lymphoma. PET/CT had a high PPV for aggressive B-cell lymphoma with diffuse bone marrow FDG uptake and high NPVs for excluding bone marrow involvement in aggressive B-cell lymphoma and Hodgkin's lymphoma. Bone marrow biopsy may be omitted for the above subgroups of patients with medical conditions not suitable for this procedure. For patients with indolent B-cell lymphoma, bone marrow biopsy is still an indispensable procedure for staging.