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

• Published in: International journal of radiation oncology, biology, physics Vol. 90; no. 4; pp. 877 - 885
• Main Authors: Badiyan, Shahed N., MD, Markovina, Stephanie, MD, PhD, Simpson, Joseph R., MD, PhD, Robinson, Clifford G., MD, DeWees, Todd, PhD, Tran, David D., MD, PhD, Linette, Gerry, MD, Jalalizadeh, Rohan, BS, Dacey, Ralph, MD, Rich, Keith M., MD, Chicoine, Michael R., MD, Dowling, Joshua L., MD, Leuthardt, Eric C., MD, Zipfel, Gregory J., MD, Kim, Albert H., MD, PhD, Huang, Jiayi, MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.11.2014
• Subjects: Adult; Aged; Antineoplastic Agents, Alkylating - therapeutic use; BIOPSY; Brain Neoplasms - drug therapy; Brain Neoplasms - mortality; Brain Neoplasms - radiotherapy; Combined Modality Therapy - methods; COMPARATIVE EVALUATIONS; Dacarbazine - analogs & derivatives; Dacarbazine - therapeutic use; DIAGNOSIS; Disease-Free Survival; DOSE EQUIVALENTS; Dose Fractionation; Female; Follow-Up Studies; Glioblastoma - drug therapy; Glioblastoma - mortality; Glioblastoma - radiotherapy; GLIOMAS; Hematology, Oncology and Palliative Medicine; Humans; Maintenance Chemotherapy - methods; Male; Middle Aged; MULTIVARIATE ANALYSIS; PATIENTS; RADIATION DOSES; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; RADIOTHERAPY; Radiotherapy Planning, Computer-Assisted - methods; REVIEWS; Treatment Outcome; Young Adult
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2014.07.014

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 Moderate radiation therapy dose escalation above 60 Gy with concurrent TMZ does not seem to improve clinical outcomes for patients with GBM.