Page 20 - 18F-FDG PET as biomarker in aggressive lymphoma; technical and clinical validation

Chapter 1
has been evaluated with central imaging review, this review process was optimized (regarding ease of use and speed of the viewer, improvements of instruction manuals and clinical record forms) for future HOVON studies.
This thesis is a result of the research questions and PETRA interim [18F]FDG PET project outlined above. Part I: what is known about the predictive value of interim [18F]FDG PET in HL and DLBCL patients? Part II: what is the interobserver agreement of using the Deauville criteria in interim [18F]FDG PET? Part III: is the predictive value of interim [18F]FDG PET also valid in other DLBCL patient cohorts and what interim [18F]FDG PET criteria predict best for progression-free survival?
Part I of this thesis consists of overviews of the current evidence on interim [18F] FDG PET and its role in clinical practice in DLBCL. Chapter 2 summarizes the evidence why interim [18F]FDG PET adapted therapy is (becoming) a clinical reality for HL.The evidence for DLBCL shows a high negative predictive value of interim [18F]FDG PET but a less favorable positive predictive value. Besides that, switching therapy to currently available salvage therapies may not overcome early treatment resistance in DLBCL. In addition to this narrative review, a systematic review and meta-analysis was performed on the predictive value of visual response criteria used for interim [18F]FDG PET in DLBCL (Chapter 3).
Part II is a more methodological part and focusses on important prerequisites for the technical validation of interim [18F]FDG PET. Chapter 4 describes the interobserver agreement of interim and end-of-treatment [18F]FDG PET assessment with the Deauville 5-point scale by nuclear medicine physicians in the HOVON-84 study. Chapter 5 is a pilot study on baseline [18F]FDG PET scans focussing on workflow optimization strategies for a fast, robust and reliable (in terms of interobserver agreement) assessment of metabolic tumor volume.
Part III of this thesis comprises the clinical validation of interim [18F]FDG PET in 2 HOVON studies and in an individual patient data meta-analysis of studies included in the PETRA database. Chapter 6 is divided into 2 parts. Part A details the assessment of interim [18F]FDG PET in the HOVON-84 study and compares the Deauville score and the semi-quantitative ∆SUVmax criteria in terms of predictive value and shows the added value of interim [18F]FDG PET
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