title: The Gordian knot of interim 18-fluorodeoxyglucose positron emission tomography for Hodgkin lymphoma: a meta-analysis and commentary on published studies.
abstract: We assessed the diagnostic performance of interim 18-fluorodeoxyglucose positron emission tomography (FDG-PET) with regard to the final outcome of adult patients with newly diagnosed Hodgkin lymphoma (HL). The predefined outcome was treatment failure at the end of follow-up. Bivariate meta-analysis of diagnostic data was used to calculate combined (pooled) estimates. Demographics, quality data and study characteristics were used as potential moderators of outcome in subgroup analysis and meta-regression. A total of 14 studies (16 arms stratified by staging or therapy, 1328 evaluable patients) were deemed eligible for final analysis, after excluding intention-to-treat studies (i.e. those where treatment decision was based on interim PET). The combined effect (95% confidence interval) for sensitivity was 0.67 (0.57-0.76) and specificity 0.89 (0.84-0.93). The corresponding likelihood ratios (LRs) were 6.2 (3.9-10.0) for LR + and 0.37 (0.27-0.50) for LR -, with moderate heterogeneity (I(2) =67%). The estimated negative predictive value was 0.93 (0.85-1.00). The diagnostic performance was influenced by most covariates tested, including age, duration of follow-up, criteria used and time of interim PET. Interim PET retains a high specificity for final outcome, but the sensitivity is low. The use of a PET + study as a surrogate marker is hampered by inconsistent interpretation criteria and study populations. However, the high negative predictive value may permit treatment stratification based on a negative outcome.
authors.affiliation: Department of Pathophysiology, University of Athens, Greece. pd.ziakas@gmail.com
authors.forename: Panayiotis D
authors.initials: PD
authors.lastname: Ziakas
authors.forename: Loukia S
authors.initials: LS
authors.lastname: Poulou
authors.forename: Michael
authors.initials: M
authors.lastname: Voulgarelis
authors.forename: Loukas
authors.initials: L
authors.lastname: Thanos
mesh_terms: D000328:Adult; D005260:Female; D019788:Fluorodeoxyglucose F18; D006689:Hodgkin Disease / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D006801:Humans; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18