BACKGROUND.
Efforts to improve local control and survival by increasing the dose of once-daily radiation therapy beyond 70 Gray (Gy) for patients with malignant gliomas have as yet been unsuccessful. Hyperfractionated radiation therapy (HF) should allow for delivery of a higher total dose without increasing normal tissue late effects, whereas accelerated hyperfractionated radiation therapy (AHF) may minimize tumor repopulation by shortening overall treatment time. The Radiation Therapy Oncology Group (RTOG) conducted a randomized Phase 1/11 study of escalating doses of HF and AHF with carmustine (bis-chloroethyl nitrosourea [BCNU]) for adults with supratentorial glioblastoma multiforme (GBM) or anaplastic astrocytoma (AA). Primary study endpoints were overall survival and acute and chronic treatment-related toxicity.
METHODS.
From 1983 to 1989, 786 patients with supratentorial gliomas (81% with GBM and 19% with AA) were stratified by histology, age, and performance status and randomized to receive partial brain irradiation, utilizing either HF (1.2 Gy twice daily to doses of 64.8, 72, 76.8, or 81.6 Gy) or AHF (1.6 Gy twice daily to doses of 48 or 54.4 Gy). All patients received carmustine. The distribution of prognostic factors was similar in all arms.