title: Pseudoprogression following chemoradiotherapy for glioblastoma multiforme.
abstract: OBJECTIVE
  Pseudoprogression (psPD) is now recognised following radiotherapy with concurrent temozolomide (RT/TMZ) for glioblastoma multiforme (GBM). The aim of this study was to determine the incidence of psPD following RT/TMZ and the effect of psPD on prognosis.
  
  
  METHODS
  All patients receiving RT/TMZ for newly diagnosed GBM were identified from a prospective database. Clinical and radiographic data were retrospectively reviewed. Early progression was defined as radiological progression (RECIST criteria) during or within eight weeks of completing RT/TMZ. Pseudoprogression was defined as early progression with subsequent disease stabilization, without salvage therapy, for at least six months from completion of RT/TMZ. The primary outcome was overall survival (Kaplan-Meier) and log rank analysis was used to compare groups.
  
  
  RESULTS
  Out of 111 patients analyzed, 104 were evaluable for radiological response. Median age was 58 years and median follow-up 55 weeks. Early progression was confirmed in 26% and within this group 32% had psPD. Median survival for the whole cohort was 56.7 weeks [95% CI (51.0, 71.3)]. Median survival for patients with psPD was significantly higher than for patients with true early progression (124.9 weeks versus 36.0 weeks, p = 0.0286).
  
  
  CONCLUSIONS
  Approximately one third of patients with early progression were found to have psPD which was associated with a favourable prognosis. Maintenance TMZ should not be abandoned on the basis of seemingly discouraging imaging features identified within the first three months after RT/TMZ.
authors.affiliation: Odette Cancer Centre, University of Toronto, Ontario, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Sanghera
authors.forename: James
authors.initials: J
authors.lastname: Perry
authors.forename: Arjun
authors.initials: A
authors.lastname: Sahgal
authors.forename: Sean
authors.initials: S
authors.lastname: Symons
authors.forename: Richard
authors.initials: R
authors.lastname: Aviv
authors.forename: Meredith
authors.initials: M
authors.lastname: Morrison
authors.forename: Kelvin
authors.initials: K
authors.lastname: Lam
authors.forename: Phillip
authors.initials: P
authors.lastname: Davey
authors.forename: May N
authors.initials: MN
authors.lastname: Tsao
mesh_terms: D018906:Antineoplastic Agents, Alkylating / Q000009:adverse effects / Q000627:therapeutic use*; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000532:radiotherapy; D003131:Combined Modality Therapy; D003606:Dacarbazine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D018450:Disease Progression; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000188:drug therapy* / Q000401:mortality / Q000532:radiotherapy; D006801:Humans; D008279:Magnetic Resonance Imaging; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects; D012189:Retrospective Studies; D016019:Survival Analysis; D000077204:Temozolomide; D016896:Treatment Outcome
chemical_list: D018906:Antineoplastic Agents, Alkylating; D003606:Dacarbazine; D000077204:Temozolomide