Hyperfractionated radiation therapy for incompletely resected supratentorial low-grade glioma. A phase II study

Background and purpose: In order to investigate the feasibility, toxicity a nd antitumor efficacy of hyperfractionated radiation therapy, 37 adult pati ents with incompletely resected supratentorial low-grade glioma were entere d into a phase II study. Materials and methods: The radiation therapy dose was 55 Gy in 50 fractions in 25 treatment days over 5 weeks to the tumor plus a 2-cm margin, with an additional 17.6 Gy given in 16 fractions in 8 treatment days over 1.5 week s to the tumor plus a 1-cm margin, using 1.1 Gy b.i.d. fractionation with a 6 h interfraction interval. The total tumor dose was 72.6 Gy in 66 fractio ns in 33 treatment days over 6.5 weeks. Results: The median survival time (MST) for all 37 patients has not yet bee n attained, while 5- and 7-year survival rates were 75% and 69%, respective ly. The median time to tumor progression (MTP) has also not yet been attain ed, while 5- and 7-year progression-free survival (PFS) rates were both 70% . There was no difference in survival or PFS regarding histology, although patients with oligodendroglioma and mixed glioma had similar survival, both being higher than that of ordinary astrocytoma. On univariate analysis of potential prognostic factors, age, Karnofsky performance status (KPS), neur ologic status and extent of surgery were found to influence survival. The t oxicity of HFX RT was generally assessed as mild to moderate. Conclusion: HFX RT is feasible with mild to moderate toxicity. Further stud ies are warranted with more patients and longer follow-up before testing it against standard fractionation RT in this patient population. (C) 1998 Els evier Science Ireland Ltd. All rights reserved.