Abstract P062

Correlating 18FDG-PET/CT- and CT-derived Biomarkers to Neutrophil Extracellular Traps in Classical Hodgkin Lymphoma

Introduction: Accumulation of neutrophil extracellular traps (NETs), neutrophil-derived networks of decondensed chromatin and granule proteins, is associated to worse prognosis in many cancer types. To investigate their role in malignant lymphoma, we measured NETs in plasma in patients with classical Hodgkin lymphoma (cHL) and high-grade B-cell lymphomas (HGBCL) and found that NETs were associated with inflammation and worse patient outcome in univariate survival analyses. Here, the biology of NETs and inflammation in cHL was further explored using tumour and body composition data derived from 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18FDG-PET/CT) and CT scans.

Methods: NETs were measured in plasma taken at diagnosis in 113 cHL and 222 HGBCL patients from the Swedish U-CAN biobank with an ELISA targeting citrullinated histone complexes. Clinical data and routine blood counts at diagnosis were available for all included patients. Semi-automated tumour lesion segmentations of lesions with standardized uptake value (SUV) ≥ 4 were generated in 87 cHL baseline 18FDG-PET/CT scans, in order to extract data on total metabolic tumour volume (TMTV), maximum distance between tumour lesions (Dmax), maximum SUV (SUVmax) and lesion count. Furthermore, Body and Organ Analysis (BOA) was used on the corresponding CT scans to generate data on muscle mass and total (TAT) and visceral (VAT) adipose tissue volume.

Results: TMTV, Dmax and lesion count correlated positively to the plasma NET levels. Higher TMTV and SUVmax were associated with worse progression-free survival, with similar although non-significant trends for overall survival. Dmax and lesion count did not significantly correlate to patient outcome. No associations were observed between plasma NET levels and muscle mass, TAT or VAT. Other inflammatory blood counts investigated in the study also showed correlations to the 18FDG-PET/CT imaging biomarkers, but not to the muscle mass, TAT or VAT of the patients.

Conclusions: In cHL, NETs showed an association with 18FDG-PET/CT imaging biomarkers representing increased tumour burden and dissemination, but not with CT-based body composition parameters. These findings indicate that increased NET levels may reflect biological processes linked to tumour burden and tumour-induced inflammation, rather than chronic inflammation and alterations in the metabolic status of the patients. Additional patients will be included in the study.