title: Different predictive values of interim18F-FDG PET/CT in germinal center like and non-germinal center like diffuse large B-cell lymphoma.
abstract: OBJECTIVE
  Diffuse large B-cell lymphoma (DLBCL) is a pathologically heterogeneous disease with different prognoses according to its molecular profiles. Despite the broad usage of18F-fluoro-2-dexoxy-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT), previous studies that have investigated the value of interim18F-FDG PET/CT in DLBCL have given the controversial results. The purpose of this study was to evaluate the prognostic value of interim18F-FDG PET/CT in DLBCL according to germinal center B cell-like (GCB) and non-GCB molecular profiling.
  
  
  METHODS
  We enrolled 118 newly diagnosed DLBCL patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP). Interim18F-FDG PET/CT scans performed after 2 or 3 cycles of R-CHOP treatment were evaluated based on the Lugano response criteria. Patients were grouped as GCB or non-GCB molecular subtypes according to immunohistochemistry results of CD10, BCL6, and MUM1, based on Hans' algorithm.
  
  
  RESULTS
  In total 118 DLBCL patients, 35 % were classified as GCB, and 65 % were classified as non-GCB. Interim PET/CT was negative in 70 %, and positive in 30 %. During the median follow-up period of 23 months, the positive interim18F-FDG PET/CT group showed significantly inferior progression free survival (PFS) compared to the negative interim18F-FDG PET/CT group (P = 0.0004) in entire patients. A subgroup analysis according to molecular profiling demonstrated significant difference of PFS between the positive and negative interim18F-FDG PET groups in GCB subtype of DLBCL (P = 0.0001), but there was no significant difference of PFS between the positive and negative interim18F-FDG PET groups in non-GCB subtype of DLBCL.
  
  
  CONCLUSIONS
  Interim18F-FDG PET/CT scanning had a significant predictive value for disease progression in patients with the GCB subtype of DLBCL treated with R-CHOP, but not in those with the non-GCB subtype. Therefore, molecular profiles of DLBCL should be considered for interim18F-FDG PET/CT practice.
authors.affiliation: Department of Nuclear Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro, 173 Beon-gil, Bundang-gu, Seongnam, 13620, Republic of Korea.
authors.forename: Jihyun
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro, 173 Beon-gil, Bundang-gu, Seongnam, 13620, Republic of Korea.
authors.forename: Jeong-Ok
authors.initials: JO
authors.lastname: Lee
authors.affiliation: Department of Pathology, Seoul National University Bundang Hospital, 82 Gumi-ro, 173 Beon-gil, Bundang-gu, Seongnam, 13620, Republic of Korea.
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Paik
authors.affiliation: Department of Nuclear Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro, 173 Beon-gil, Bundang-gu, Seongnam, 13620, Republic of Korea.
authors.forename: Won Woo
authors.initials: WW
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro, 173 Beon-gil, Bundang-gu, Seongnam, 13620, Republic of Korea.|Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.|Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, 864-1 Iui-dong, Yeongtong-gu, Suwon, 443-270, Republic of Korea.
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro, 173 Beon-gil, Bundang-gu, Seongnam, 13620, Republic of Korea. yosung99@hanmail.net.
authors.forename: Yoo Sung
authors.identifier: http://orcid.org/0000-0001-7985-1358
authors.initials: YS
authors.lastname: Song
mesh_terms: D019788:Fluorodeoxyglucose F18; D018858:Germinal Center; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000276:immunology; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: Interim positron emission tomography; Lymphoma, large B-cell, diffuse; Molecular profiling; Prognosis