title: The addition of temozolomide does not change the pattern of progression of glioblastoma multiforme post-radiotherapy.
abstract: BACKGROUND
  To determine whether the pattern of progressive disease (PD) for glioblastoma multiforme (GBM) patients has changed with the introduction of the current standard of care protocol - postoperative conformal radiotherapy to a dose of 60 Gray in 30 fractions with concurrent low-dose (75-100 mg/m(2) ) temozolomide, followed by six cycles of adjuvant high-dose (150-200 mg/m(2) ) temozolomide - as compared with radiotherapy alone.
  
  
  METHODS
  For GBM patients commencing combined modality treatment between October 2005 and August 2009, the MRI scan confirming progression (if any) was co-registered with the original planning CT scan, and progression site(s) marked. Coverage of the composite progression volume (PDvol) by the original 95% prescription isodose volume was obtained from dose-volume histogram (DVH) data, and assigned as 'central', 'in field', 'marginal' and 'out of field', corresponding to >95%, >80%, 20-80% and <20% coverage.
  
  
  RESULTS
  Of 68 consecutive patients identified, 54 (79.4%) had documented PD. Of the 47 (87%) evaluable patients, 43 (91%) had in field progression with 36 (77%) of these being central. Of the remaining four cases, three (6%) had marginal progression, and only one patient (2%) had out of field progression. Median overall and progression-free survival were 11.6 and 6.6 months, respectively.
  
  
  CONCLUSIONS
  The pattern of progression in our GBM patients does not appear to have been altered by the addition of temozolomide. The overwhelming majority of first PD occurred within the original radiotherapy planning target volume, as is the case in patients treated with radiotherapy alone. Major changes to radiotherapy volumes are not indicated, with alternative strategies required to improve outcomes.
authors.affiliation: Dentistry and Health Sciences, the University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Ashray
authors.initials: A
authors.lastname: Gunjur
authors.forename: Mathias
authors.initials: M
authors.lastname: Bressel
authors.forename: Gail
authors.initials: G
authors.lastname: Ryan
mesh_terms: D000328:Adult; D000368:Aged; D018906:Antineoplastic Agents, Alkylating / Q000008:administration & dosage; D001932:Brain Neoplasms / Q000401:mortality* / Q000628:therapy; D017024:Chemotherapy, Adjuvant / Q000379:methods / Q000401:mortality; D003606:Dacarbazine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D018450:Disease Progression; D005260:Female; D005909:Glioblastoma / Q000401:mortality* / Q000628:therapy*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D020266:Radiotherapy, Conformal / Q000401:mortality*; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate; D000077204:Temozolomide; D016896:Treatment Outcome; D014739:Victoria / Q000453:epidemiology
chemical_list: D018906:Antineoplastic Agents, Alkylating; D003606:Dacarbazine; D000077204:Temozolomide