Large dose fraction radiotherapy in the treatment of glioblastoma.

Twenty-four adults with glioblastoma multiforme (astrocytoma, grade 4) underwent postoperative large dose fraction radiotherapy (LDFR; 5 Gy twice weekly) with Linac X-rays. The outcome in this group was compared with that of 26 patients who received conventional fractionated radiotherapy (CFR; 2 Gy 5 times weekly). The time, dose, and fractionation (TDF) factor was about 100 in both groups. The survival rates following LDFR and CFR were, respectively, 63% vs 65% at 1 year; 36% vs 8% at 2 years; 17% vs 4% at 3 years; and 4% vs 0% at 5 years. Although the survival curve for LDFR was superior to that for CFR, the difference was not statistically significant. Autopsies of nine LDFR and 13 CFR patients showed no residual tumor in one case and no cases, respectively; small residual tumor in three cases in each group; extensive coagulation necrosis of the tumor and surrounding brain tissue in one LDFR and four CFR patients; tumor proliferation in three LDFR and four CFR cases; and mixed glioblastoma and fibrosarcoma in one LDFR and two CFR patients. These results suggest that maximum tumor removal followed by LDFR may offer a better prognosis for patients with glioblastoma than that offered by surgery plus CFR.