title: 18F-FDG PET is an independent outcome predictor in primary central nervous system lymphoma.
abstract: Primary central nervous system (CNS) lymphoma is an aggressive non-Hodgkin lymphoma with poor prognosis. We evaluated pretreatment (18)F-FDG PET as a prognostic marker in primary CNS lymphoma.
  
  
  METHODS
  Forty-two immunocompetent patients with newly diagnosed primary CNS lymphoma who underwent pretreatment (18)F-FDG PET were retrospectively analyzed. Baseline status and response to treatment were evaluated by MR imaging. Tumor maximum standardized uptake values were assessed by volume-of-interest analyses using an automatic isocontour definition. A 10-step semiquantitative visual rating system (metabolic imaging lymphoma aggressiveness scale, or MILAS) was used to assess primary CNS lymphoma metabolism as a marker of clinical aggressiveness. Logistic regression, log-rank testing, and multivariable Cox regression were used to investigate the association between (18)F-FDG uptake and tumor response and survival.
  
  
  RESULTS
  Mean maximum standardized uptake value correlated linearly with MILAS. The distribution of patients according to MILAS (0-9) was 0%, 28.6%, 23.8%, 21.4%, 11.9%, 4.8%, 7.1%, 0%, 0%, and 2.4%. There was no correlation between MILAS and response to treatment. Respective 2- and 5-y survival rates were 52% and 32% for progression-free survival (PFS) and 64% and 50% for overall survival (OS). A cutoff at MILAS 3 was a good separator for PFS (median: 54.7 mo [≤3], 3.8 mo [>3], P = 0.0272) and OS (median: not reached [≤3], 13.8 mo [>3], P = 0.131). In multivariable analyses, increasing MILAS was significantly associated with shorter PFS (hazard ratio, 1.49, P = 0.006) and OS (hazard ratio, 1.43, P = 0.018).
  
  
  CONCLUSIONS
  Increased pretreatment (18)F-FDG uptake may offer new opportunities for baseline risk evaluation in untreated primary CNS lymphoma.
authors.affiliation: Department of Hematology/Oncology, Freiburg University Medical Center, Freiburg, Germany. kasendab@uhbs.ch
authors.forename: Benjamin
authors.initials: B
authors.lastname: Kasenda
authors.forename: Vanessa
authors.initials: V
authors.lastname: Haug
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Schorb
authors.forename: Kristina
authors.initials: K
authors.lastname: Fritsch
authors.forename: Jürgen
authors.initials: J
authors.lastname: Finke
authors.forename: Michael
authors.initials: M
authors.lastname: Mix
authors.forename: Claudia
authors.initials: C
authors.lastname: Hader
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Weber
authors.forename: Gerald
authors.initials: G
authors.lastname: Illerhaus
authors.forename: Philipp T
authors.initials: PT
authors.lastname: Meyer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology; D016543:Central Nervous System Neoplasms; D018572:Disease-Free Survival; D005260:Female; D019788:Fluorodeoxyglucose F18; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D016016:Proportional Hazards Models; D012044:Regression Analysis; D012189:Retrospective Studies; D012306:Risk; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
chemical_list: D005819:Genetic Markers; D019788:Fluorodeoxyglucose F18