926P - Reader variability of PET/CT-based response criteria in DLBCL and association to outcome

Date 08 October 2016
Event ESMO 2016 Congress
Session Poster Display
Topics Haematological Malignancies
Presenter EUN JI Han
Citation Annals of Oncology (2016) 27 (6): 313-327. 10.1093/annonc/mdw375
Authors E.J. Han, W.H. Choi, J.H. O
  • Radiology, The Catholic University of Korea, 06591 - Seoul/KR

Abstract

Background

F-18-fluoro-2-deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is essentially recommended for monitoring response to treatment in patients with diffuse large B cell lymphoma (DLBCL) and qualitative interpretation is commonly applied in clinical practice. We aimed to evaluate interobserver agreements of qualitative PET/CT-based response criteria and evaluate predictive value of PET/CT results by each reader for outcome.

Methods

FDG PET/CT images were obtained for patients with DLBCL at baseline, at interim after 3 cycles of first-line chemotherapy and after completion of chemotherapy. Two nuclear medicine physicians (with 3 and 8 years of experience with FDG PET/CT) blinded to clinical data retrospectively assessed response to chemotherapy using visual qualitative analyses from the International Working Group (IWG) criteria and Lugano classification, respectively. The associations between PET/CT results and progression-free survival (PFS) and overall survival (OS) were assessed using Cox regression analysis.

Results

Included were 112 PET/CT images from 59 patients with DLBCL (36 male, 23 female; mean age 53 ± 14 years). In interpretation using binary scoring system from IWG criteria, interobserver agreement was substantial (Cohen's ĸ = 0.76) with absolute agreement consistency of 89%. In interpretation using Deauville five-point scale from Lugano classification, interobserver agreement was moderate (Cohen's weighted ĸ = 0.54) and absolute consistency was 62%. The most common cause of disagreements was discordant interpretation of presence of residual tumor uptake. With mean follow-up period of 88 months, estimated 5-year PFS and OS were 81% and 92%, respectively. Neither interim nor post-treatment PET/CT results by both readers were significantly associated with PFS. Interim PET/CT result using Deauville scale was the only significant factor for OS.

Conclusions

Moderate to substantial interobserver agreement was observed for response assessment according to visual analysis and interim PET/CT result could predict OS in patients with DLBCL. Further studies are necessary to validate completely PET/CT-based response criteria and further standardize and consistent PET/CT interpretation.

Legal entity responsible for the study

N/A

Funding

N/A

Disclosure

All authors have declared no conflicts of interest.