title: Patterns of failure for glioblastoma multiforme following limited-margin radiation and concurrent temozolomide.
abstract: BACKGROUND
  To analyze patterns of failure in patients with glioblastoma multiforme (GBM) treated with limited-margin radiation therapy and concurrent temozolomide. We hypothesize that patients treated with margins in accordance with Adult Brain Tumor Consortium guidelines (ABTC) will demonstrate patterns of failure consistent with previous series of patients treated with 2-3 cm margins.
  
  
  METHODS
  A retrospective review was performed of patients treated at the University of Alabama at Birmingham for GBM between 2000 and 2011. Ninety-five patients with biopsy-proven disease and documented disease progression after treatment were analyzed. The initial planning target volume includes the T1-enhancing tumor and surrounding edema plus a 1 cm margin. The boost planning target volume includes the T1-enhancing tumor plus a 1 cm margin. The tumors were classified as in-field, marginal, or distant if greater than 80%, 20-80%, or less than 20% of the recurrent volume fell within the 95% isodose line, respectively.
  
  
  RESULTS
  The median progression-free survival from the time of diagnosis to documented failure was 8 months (range 3-46). Of the 95 documented recurrences, 77 patients (81%) had an in-field component of treatment failure, 6 (6%) had a marginal component, and 27 (28%) had a distant component. Sixty-three patients (66%) demonstrated in-field only recurrence.
  
  
  CONCLUSIONS
  The low rate of marginal recurrence suggests that wider margins would have little impact on the pattern of failure, validating the use of limited margins in accordance ABTC guidelines.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Gebhardt
authors.forename: Michael C
authors.initials: MC
authors.lastname: Dobelbower
authors.forename: William H
authors.initials: WH
authors.lastname: Ennis
authors.forename: Asim K
authors.initials: AK
authors.lastname: Bag
authors.forename: James M
authors.initials: JM
authors.lastname: Markert
authors.affiliation: University of Alabama at Birmingham, 1700 6th Ave, South, Birmingham, AL 35233, USA. jfiveash@uab.edu.
authors.forename: John B
authors.initials: JB
authors.lastname: Fiveash
mesh_terms: D000328:Adult; D000368:Aged; D018906:Antineoplastic Agents, Alkylating / Q000627:therapeutic use*; D001932:Brain Neoplasms / Q000473:pathology / Q000628:therapy*; D059248:Chemoradiotherapy; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000473:pathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000628:therapy; D009367:Neoplasm Staging; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal; D012189:Retrospective Studies; D000077204:Temozolomide; D017211:Treatment Failure; D055815:Young Adult
chemical_list: D018906:Antineoplastic Agents, Alkylating; D003606:Dacarbazine; D000077204:Temozolomide