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Title: Radiation Therapy Dose Escalation for Glioblastoma Multiforme in the Era of Temozolomide

Purpose: To review clinical outcomes of moderate dose escalation using high-dose radiation therapy (HDRT) in the setting of concurrent temozolomide (TMZ) in patients with newly diagnosed glioblastoma multiforme (GBM), compared with standard-dose radiation therapy (SDRT). Methods and Materials: Adult patients aged <70 years with biopsy-proven GBM were treated with SDRT (60 Gy at 2 Gy per fraction) or with HDRT (>60 Gy) and TMZ from 2000 to 2012. Biological equivalent dose at 2-Gy fractions was calculated for the HDRT assuming an α/β ratio of 5.6 for GBM. Results: Eighty-one patients received SDRT, and 128 patients received HDRT with a median (range) biological equivalent dose at 2-Gy fractions of 64 Gy (61-76 Gy). Overall median follow-up time was 1.10 years, and for living patients it was 2.97 years. Actuarial 5-year overall survival (OS) and progression-free survival (PFS) rates for patients that received HDRT versus SDRT were 12.4% versus 13.2% (P=.71), and 5.6% versus 4.1% (P=.54), respectively. Age (P=.001) and gross total/near-total resection (GTR/NTR) (P=.001) were significantly associated with PFS on multivariate analysis. Younger age (P<.0001), GTR/NTR (P<.0001), and Karnofsky performance status ≥80 (P=.001) were associated with improved OS. On subset analyses, HDRT failed to improve PFS or OS for those aged <50 years or those who had GTR/NTR. Conclusion: Moderatemore » radiation therapy dose escalation above 60 Gy with concurrent TMZ does not seem to improve clinical outcomes for patients with GBM.« less
Authors:
; ; ; ;  [1] ; ;  [2] ;  [1] ; ; ; ; ; ; ;  [3] ;  [1]
  1. Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States)
  2. Division of Medical Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri (United States)
  3. Department of Neurosurgery, Washington University School of Medicine, St. Louis, Missouri (United States)
Publication Date:
OSTI Identifier:
22420477
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 90; Journal Issue: 4; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; BIOPSY; COMPARATIVE EVALUATIONS; DIAGNOSIS; DOSE EQUIVALENTS; GLIOMAS; MULTIVARIATE ANALYSIS; PATIENTS; RADIATION DOSES; RADIOTHERAPY; REVIEWS