FDG-PET is prognostic and predictive for progression-free survival in relapsed follicular lymphoma: exploratory analysis of the GAUSS study

Abstract

An exploratory analysis of 75 follicular lymphoma patients treated with obinutuzumab or rituximab induction therapy (IT) for 4 weeks in the phase II GAUSS study aimed to determine whether positron emission tomography (PET) results could predict progression-free survival (PFS) and tumor response. The proportion of patients with a PFS event (progression or death) was higher in those who were PET-positive after IT (assessed using Deauville five-point scale criteria; 35/52, 67%) than PET-negative (5/20, 25%); the hazard ratio for progression or death was 0.25 (95%CI: 0.01-0.64; p = 0.0018). A significant association was also found when PET results were assessed using International Harmonization Project and European Organisation for Research and Treatment of Cancer criteria. Change between baseline and end of IT in values of standardized uptake value and other PET parameters were associated with PFS and response. Validation of these results in prospective studies of larger cohorts is warranted.

<p>Prognostic values of baseline, interim and end-of therapy ¹⁸F-FDG PET/CT in patients with follicular lymphoma</p>

“…The utility of PET/CT in assessing response after end-of treatment has been confirmed in several studies 6,11,19,32. In accordance with previous findings, our study confirmed that E-PET had predictive value for PFS in FL patients, and PFS in PET-positive patients was significantly lower compared with PET-negative patients.…”

“…The interim and end-of treatment PET/CT results were assessed according to the IHP18 and D-5PS19 criteria. For IHP criteria, FDG uptake greater than the uptake of the mediastinum in lesions greater than or equal to 2 cm and more than the adjacent background tissue in lesions less than 2 cm represented residual disease.…”

Prognostic value of end-of-induction PET response after first-line immunochemotherapy for follicular lymphoma (GALLIUM): secondary analysis of a randomised, phase 3 trial

“…Notwithstanding this finding, minimal residual disease analysis is showing some promise as a prognostic tool in follicular lymphoma, There is a growing body of evidence to suggest that quantitative PET measures could be prognostic in follicular lymphoma. 26,27 Analysis of baseline total metabolic tumour volume, incorporated with pretreatment prognostic indices and metabolic response, might increase separation between the progression-free survival curves of the patients with or without a complete metabolic response, specifically to better identify the 10-15% of patients with complete metabolic response who do progress early. Further PET analyses might also contribute to improved understanding of why some patients without complete metabolic response do not progress early, particularly the obinutuzumab-treated population, for whom we hypothesise that residual 18 F-FDG-avidity could reflect inflammation related to ongoing antibody-dependent cellular cytotoxicity (one of the mechanisms of action of obinutuzumab) 28,29 immediately after induction therapy.…”

Limited benefit of additional contrast-enhanced CT to end-of-treatment PET/CT evaluation in patients with follicular lymphoma

“…Applying Deauville 5-point scale evaluation with a cut-off ≤ 3, generally used for HL and DLBCL response assessment, the role of PET/CT- based outcome prediction after first-line immuno-chemotherapy for FL was reinforced 34 . Kostakoglu et al presented results of a post induction therapy in 75 patients with FL, highlighting that variations of different PET parameters were associated with PFS and response 35 . Our current data showed high diagnostic accuracy of PET/ldCT protocol in response assessment.…”