title: CT-based versus FDG-PET/CT-based NCCN international prognostic index risk stratification in DLBCL.
abstract: BACKGROUND
  This study compared CT-based and (18)F-fluoro-2-deoxy-D-glucose PET/CT (FDG-PET/CT)-based NCCN International Prognostic Index (NCCN-IPI) risk stratification in newly diagnosed diffuse large B-cell lymphoma (DLBCL).
  
  
  METHODS
  This retrospective study included 57 patients with newly diagnosed DLBCL who had undergone both (oral and intravenous contrast-enhanced full-dose) diagnostic CT and FDG-PET/CT. Diagnostic CT only and FDG-PET/CT were evaluated separately, and corresponding NCCN-IPI scores for the 2 datasets (NCCN-IPICT and NCCN-IPIPET/CT) were calculated. Percentages of agreement and weighted k statistic between NCCN-IPICT and NCCN-IPIPET/CT scoring with regard to the formation of low-, low-intermediate-, high-intermediate-, and high-risk groups were calculated.
  
  
  RESULTS
  In 47 of 57 patients (82.5%; 95% CI, 70.4-90.4), diagnostic CT alone was in agreement with FDG-PET/CT with regard to the formation of low-, low-intermediate-, high-intermediate-, and high-risk NCCN-IPI groups, but not in the remaining 10 patients (17.5%; 95% CI, 9.6%-29.6%). All NCCN-IPI disagreements between diagnostic CT and FDG-PET/CT were from the detection of additional lesions by the latter, most of them being bone marrow lesions. Agreement between NCCN-IPICT and NCCN-IPIPET/CT with regard to the formation of low-, low-intermediate-, high-intermediate-, and high-risk groups was considered good (k=0.771).
  
  
  CONCLUSIONS
  Although agreement between NCCN-IPICT and NCCN-IPIPET/CT risk stratification is generally good, FDG-PET/CT results in higher NCCN-IPI risk stratifications in a non-negligible proportion of patients. Future studies should investigate the prognostic implications of these imaging-based differences in NCCN-IPI scoring.
authors.affiliation: From the Departments of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, and the Departments of Nuclear Medicine, Hematology, and Pathology, Meander Medical Center, Amersfoort, The Netherlands.
authors.forename: Hugo J A
authors.initials: HJ
authors.lastname: Adams
authors.affiliation: From the Departments of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, and the Departments of Nuclear Medicine, Hematology, and Pathology, Meander Medical Center, Amersfoort, The Netherlands.
authors.forename: John M H
authors.initials: JM
authors.lastname: de Klerk
authors.affiliation: From the Departments of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, and the Departments of Nuclear Medicine, Hematology, and Pathology, Meander Medical Center, Amersfoort, The Netherlands.
authors.forename: Rob
authors.initials: R
authors.lastname: Fijnheer
authors.affiliation: From the Departments of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, and the Departments of Nuclear Medicine, Hematology, and Pathology, Meander Medical Center, Amersfoort, The Netherlands.
authors.forename: Stefan V
authors.initials: SV
authors.lastname: Dubois
authors.affiliation: From the Departments of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, and the Departments of Nuclear Medicine, Hematology, and Pathology, Meander Medical Center, Amersfoort, The Netherlands.
authors.forename: Rutger A J
authors.initials: RA
authors.lastname: Nievelstein
authors.affiliation: From the Departments of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, and the Departments of Nuclear Medicine, Hematology, and Pathology, Meander Medical Center, Amersfoort, The Netherlands.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Kwee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016403:Lymphoma, Large B-Cell, Diffuse / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D019788:Fluorodeoxyglucose F18