title: Pseudoprogression in patients with glioblastoma: clinical relevance despite low incidence.
abstract: BACKGROUND
  According to the Response Assessment in Neuro-Oncology criteria, new enhancement within the radiation field on contrast enhanced T1-weighted images within 12 weeks after completion of radiotherapy should not qualify for progressive disease, since up to 50% of these cases may be pseudoprogression (PsP). To validate this concept, we assessed incidence and overall survival (OS) of patients with suspected and confirmed PsP dependent on different time intervals and definitions of PsP.
  
  
  METHODS
  Patients with newly diagnosed glioblastoma and an enhancement increase of at least 25% after completion of standard radiochemotherapy at month 1, 4, 7, or 10 were eligible. Based on the development of the enhancement in follow-up examinations, patients were categorized as either PsP (subgrouped as complete resolution/decrease >50% and decrease <50%/stable) or true progression.
  
  
  RESULTS
  Out of 548 patients, 79 fulfilled the inclusion criteria. Of these 79 patients, 9 (11.4%) showed PsP (6/45 patients at 1 month, 2/17 at 4 months, 1/9 at 7 months, and 0/8 at 10 months). Complete resolution of the enhancement was found in 1, decrease >50% in 3, decrease <50% in 2, and stable enhancement in 3 patients with PsP. Patients with PsP showed a significantly longer OS (P < .012). No difference in OS was found among PsP subgroups.
  
  
  CONCLUSIONS
  This series challenges the current concept of PsP. Even though we could confirm a prolonged OS of patients with PsP, the incidence of PsP was lower than reported previously and extended beyond 12 weeks.
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany (A.R., J.F., P.K., P.B., S.H., M.B.); Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.R., H.-P.S.); Department of Neurooncology, Neurology Clinic and National Center for Tumor Diseases, University of Heidelberg, Heidelberg, Germany (B.W., A.W., W.W.); German Cancer Consortium (DKTK) Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany (B.W., A.W., W.W.); Department of Neurology, Innsbruck Medical University, Innsbruck, Austria (M.N.).
authors.forename: Alexander
authors.initials: A
authors.lastname: Radbruch
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany (A.R., J.F., P.K., P.B., S.H., M.B.); Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.R., H.-P.S.); Department of Neurooncology, Neurology Clinic and National Center for Tumor Diseases, University of Heidelberg, Heidelberg, Germany (B.W., A.W., W.W.); German Cancer Consortium (DKTK) Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany (B.W., A.W., W.W.); Department of Neurology, Innsbruck Medical University, Innsbruck, Austria (M.N.).
authors.forename: Joachim
authors.initials: J
authors.lastname: Fladt
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany (A.R., J.F., P.K., P.B., S.H., M.B.); Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.R., H.-P.S.); Department of Neurooncology, Neurology Clinic and National Center for Tumor Diseases, University of Heidelberg, Heidelberg, Germany (B.W., A.W., W.W.); German Cancer Consortium (DKTK) Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany (B.W., A.W., W.W.); Department of Neurology, Innsbruck Medical University, Innsbruck, Austria (M.N.).
authors.forename: Philipp
authors.initials: P
authors.lastname: Kickingereder
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany (A.R., J.F., P.K., P.B., S.H., M.B.); Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.R., H.-P.S.); Department of Neurooncology, Neurology Clinic and National Center for Tumor Diseases, University of Heidelberg, Heidelberg, Germany (B.W., A.W., W.W.); German Cancer Consortium (DKTK) Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany (B.W., A.W., W.W.); Department of Neurology, Innsbruck Medical University, Innsbruck, Austria (M.N.).
authors.forename: Benedikt
authors.initials: B
authors.lastname: Wiestler
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany (A.R., J.F., P.K., P.B., S.H., M.B.); Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.R., H.-P.S.); Department of Neurooncology, Neurology Clinic and National Center for Tumor Diseases, University of Heidelberg, Heidelberg, Germany (B.W., A.W., W.W.); German Cancer Consortium (DKTK) Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany (B.W., A.W., W.W.); Department of Neurology, Innsbruck Medical University, Innsbruck, Austria (M.N.).
authors.forename: Martha
authors.initials: M
authors.lastname: Nowosielski
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany (A.R., J.F., P.K., P.B., S.H., M.B.); Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.R., H.-P.S.); Department of Neurooncology, Neurology Clinic and National Center for Tumor Diseases, University of Heidelberg, Heidelberg, Germany (B.W., A.W., W.W.); German Cancer Consortium (DKTK) Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany (B.W., A.W., W.W.); Department of Neurology, Innsbruck Medical University, Innsbruck, Austria (M.N.).
authors.forename: Philipp
authors.initials: P
authors.lastname: Bäumer
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany (A.R., J.F., P.K., P.B., S.H., M.B.); Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.R., H.-P.S.); Department of Neurooncology, Neurology Clinic and National Center for Tumor Diseases, University of Heidelberg, Heidelberg, Germany (B.W., A.W., W.W.); German Cancer Consortium (DKTK) Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany (B.W., A.W., W.W.); Department of Neurology, Innsbruck Medical University, Innsbruck, Austria (M.N.).
authors.forename: Heinz-Peter
authors.initials: HP
authors.lastname: Schlemmer
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany (A.R., J.F., P.K., P.B., S.H., M.B.); Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.R., H.-P.S.); Department of Neurooncology, Neurology Clinic and National Center for Tumor Diseases, University of Heidelberg, Heidelberg, Germany (B.W., A.W., W.W.); German Cancer Consortium (DKTK) Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany (B.W., A.W., W.W.); Department of Neurology, Innsbruck Medical University, Innsbruck, Austria (M.N.).
authors.forename: Antje
authors.initials: A
authors.lastname: Wick
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany (A.R., J.F., P.K., P.B., S.H., M.B.); Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.R., H.-P.S.); Department of Neurooncology, Neurology Clinic and National Center for Tumor Diseases, University of Heidelberg, Heidelberg, Germany (B.W., A.W., W.W.); German Cancer Consortium (DKTK) Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany (B.W., A.W., W.W.); Department of Neurology, Innsbruck Medical University, Innsbruck, Austria (M.N.).
authors.forename: Sabine
authors.initials: S
authors.lastname: Heiland
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany (A.R., J.F., P.K., P.B., S.H., M.B.); Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.R., H.-P.S.); Department of Neurooncology, Neurology Clinic and National Center for Tumor Diseases, University of Heidelberg, Heidelberg, Germany (B.W., A.W., W.W.); German Cancer Consortium (DKTK) Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany (B.W., A.W., W.W.); Department of Neurology, Innsbruck Medical University, Innsbruck, Austria (M.N.).
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wick
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany (A.R., J.F., P.K., P.B., S.H., M.B.); Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany (A.R., H.-P.S.); Department of Neurooncology, Neurology Clinic and National Center for Tumor Diseases, University of Heidelberg, Heidelberg, Germany (B.W., A.W., W.W.); German Cancer Consortium (DKTK) Clinical Cooperation Unit Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany (B.W., A.W., W.W.); Department of Neurology, Innsbruck Medical University, Innsbruck, Austria (M.N.).
authors.forename: Martin
authors.initials: M
authors.lastname: Bendszus
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000532:radiotherapy; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D005909:Glioblastoma / Q000175:diagnosis* / Q000401:mortality / Q000532:radiotherapy; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media
keywords: glioblastoma; pseudoprogression