Page 238 - 18F-FDG PET as biomarker in aggressive lymphoma; technical and clinical validation

Chapter 9
Summary
The aim of this thesis was to validate interim [18F]FDG PET as a biomarker of response in diffuse large B-cell lymphoma (DLBCL).
Part I PET as biomarker of response in lymphoma
Chapter 2 provides a review of the accuracy of interim [18F]FDG PET in DLBCL and Hodgkin lymphoma (HL) in clinical practice, including clinical trials with interim [18F]FDG PET adapted therapy, published until 2016 [1]. Based on the UK RAPID and EORTC H10 trials, both investigating a strategy with de- escalation of therapy (+-radiotherapy), it was concluded that de-escalation in HL became a real option in clinical practice [2,3]. In HL patients with advanced stage disease who do not achieve CMR assessed at interim [18F]FDG PET after 2 cycles, escalation from ABVD to the more intensive BEACOPP-escalated chemotherapy regimen seemed promising as shown by the RATHL trial [4]. Thus, for HL the interim [18F]FDG PET became important in clinical practice both for escalation of treatment as well as de-escalation of treatment [5,6]. The Dutch guideline for treatment of HL, updated in 2019, now contains a quality indicator on the response evaluation and adaptation of first-line treatment with interim [18F]FDG PET for both limited and advanced stage disease [7]. In patients with limited stage disease and a positive interim [18F]FDG PET the guideline advises to escalate treatment to 2x BEACOPP-escalated followed by involved node radiotherapy. For patients with advanced stage disease and a positive interim [18F]FDG PET treatment with 4x BEACOPP-escalated and additional radiotherapy on positive lesions at end of treatment. For limited stage disease patients treated with ABVD and a negative interim [18F]FDG PET, treatment will be continued with either radiotherapy or AVD (without bleomycin) combined with radiotherapy, depending on presence of baseline risk factors. For advanced stage disease and a negative interim [18F]FDG PET treatment is continued with either 4x AVD (in case of ABVD treatment) or 2x BEACOPP-escalated (in case of BEACOPP-escalated treatment) [7].
However, in 2016 there was no evidence for the use of interim[18F]FDG PET for treatment de-escalation or escalation in clinical practice for DLBCL yet. Only preliminary published data and data presented in abstract form suggest that
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