title: Salvage reirradiation for recurrent glioblastoma with radiosurgery: radiographic response and improved survival.
abstract: OBJECTIVE
  To determine the radiographic and clinical efficacy of stereotactic single dose radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) as salvage therapy for glioblastoma (GBM) at recurrence.
  
  
  METHODS
  Thirty-six patients with pathologically proven recurrent GBM were treated with salvage reirradiation by either SRS or FSRT between March of 2001 and August of 2006. Thirty-one patients had an initial diagnosis of GBM. Five patients had a malignant transformation. All patients had received radiotherapy with a dose of 50-60 Gy, a median 13.6 months prior to reirradiation (range: 0.8-119 months). At the time of recurrence, 26 patients were treated with SRS with a median dose of 18 Gy (range: 12-20 Gy). FSRT was performed in ten patients with a dose of 36 Gy in six fractions, twice weekly. Follow-up included MRI and clinical examination every 2 months.
  
  
  RESULTS
  Median survival time after SRS was 8.5 months, compared to 7.4 months after FSRT (P = 0.81). Of 26 patients treated with SRS, radiographic tumor response or stable disease was observed in eight (35%) patients and tumor progression was seen in 18 (65%) patients. Of 10 patients treated by FSRT, radiographic tumor response or stable disease was observed in four (40%) patients and tumor progression was observed in four (40%) patients (two lost to follow-up). Patients who responded to treatment had statistically improved survival compared to non-responders, with median survival of 15.8 vs. 7.3 months (P < 0.05).
  
  
  CONCLUSIONS
  Salvage reirradiation with SRS or FSRT for recurrent GBM results in radiographic response in a proportion of patients. Survival was significantly improved among patients who either responded or had stable disease after salvage reirradiation, compared to non-responders. Further study is warranted to investigate the method and time of reirradiation for recurrent GBM.
authors.affiliation: Henry Ford Health System, Detroit, MI, USA. mpatel2@hfhs.org
authors.forename: Mehul
authors.initials: M
authors.lastname: Patel
authors.forename: Farzan
authors.initials: F
authors.lastname: Siddiqui
authors.forename: Jian-Yue
authors.initials: JY
authors.lastname: Jin
authors.forename: Tom
authors.initials: T
authors.lastname: Mikkelsen
authors.forename: Mark
authors.initials: M
authors.lastname: Rosenblum
authors.forename: Benjamin
authors.initials: B
authors.lastname: Movsas
authors.forename: Samuel
authors.initials: S
authors.lastname: Ryu
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000401:mortality / Q000601:surgery*; D005260:Female; D005909:Glioblastoma / Q000401:mortality / Q000601:surgery*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000601:surgery*; D016634:Radiosurgery / Q000379:methods*; D012189:Retrospective Studies; D016879:Salvage Therapy / Q000379:methods*