Systematic Review on the Additional Value of 18F-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography in Staging Follicular Lymphoma

Purpose: This study aimed to systematically review the additional value of F-18-fluoro-2-deoxy-D-glucose positron emission tomography (FDGPET) to computed tomography (CT) for staging newly diagnosed follicular lymphoma in terms of Ann Arbor staging and Follicular Lymphoma International Prognostic Index (FLIPI) risk stratification. Materials and Methods: The PubMed/MEDLINE database was searched for relevant original studies. Included studies were methodologically assessed. Data on the frequency of FDG-PET-induced changes in Ann Arbor stage and FLIPI score relative to CTwere (meta-) analyzed when possible. Results: Seven studies with a total of 349 patients were included. Overall, studies were of very poor methodological quality, with lack of histological verification of additionally detected lesions at FDG-PETin almost all cases and only 1 study that exclusively included patients with CT-based limited nonbulky stage I to II disease. The proportion of patients whowere upstaged by FDG-PET compared with CT ranged from 0.0% to 45.2%, with a pooled summary proportion of 18.7% (95% confidence interval, 10.8%-30.4%). The single study that only included patients with CT-based limited nonbulky stage I to II disease reported FDG-PET-induced upstaging in 40.5% (95% confidence interval, 27.0%-55.5%) of cases. No study reported data on the influence of FDG-PET on FLIPI risk stratification. Conclusions: Although upstaging by FDG-PET compared with CT occurs in a considerable proportion of patients, the available studies on this topic have numerous methodological errors. Data on FDG-PET-induced FLIPI risk stratification changes relative to CT are lacking. Future welldesigned studies are needed before FDG-PET can be recommended for routine pretreatment staging of follicular lymphoma.