Evaluation of high dose Fradiotherapy (500 rads twice weekly) in cerebral glioblastoma

Twelve cases of adult cerebral glioblastomas were treated by high dose radiotherapy using Linac X-rays, and compared with 26 cases of conventional fractionated radiotherapy (200 rads 5 times weekly). The value of TDF (time, dose, and fractionation factor) was about 100 in both series. The survival rates in the high dose radiotherapy vs the conventional fractionated radiotherapy were as follows: one year survivals were 67 % vs 65 %; two year survivals 49 % vs 8 %; and three year survivals 24 % vs 4 %. The survival curve for the high dose radiotherapy group was superior to that of the conventional fractionated radiotherapy group, though there was no significant difference between them (p = 0.24). Tumor recurrences was accompanied by necrosis in most cases. Coagulative necrosis of the tumor and surrounding brain tissue was profound in the high dose radiotherapy group. In one case, no residual tumor was recognized at autopsy. In another case, resected mass lesions showed only cerebral radionecrosis at the second and third operations. No serious side effects have yet been recognized in the high dose radiotherapy group. (author)