Radiation therapy of intracranial germ cell tumors with radiosensitivity assessment

Fifty patients with pineal and/or suprasellar tumors were treated in the Department of Radiology, University of Tokyo, from 1975 to 1988. Histological diagnosis was obtained in 28 cases, whereas 22 patients were irradiated without pathological verification. Of the 28 patients with histological diagnosis, 11 had germinomas, 13 non-germinoma germ cell tumors, including nine teratomas, two choriocarcinomas and two embryonal carcinomas, two pineocytomas and two pineoblastomas. The treatment protocol since 1981 has been that, after 20 Gy is given with a local irradiation field, if tumor regression is marked and germinoma is highly suspected, whole brain or whole CNS irradiation is performed subsequently; otherwise, surgical intervention is performed followed by systemic chemotherapy plus radiation therapy. The five-year survival rates of histologically proven germinomas, histologically proven non-germinoma germ cell tumors, and clinically suspected germinomas by means of the above-mentioned method as well as tumor marker status were 73%, 28%, and 83%, respectively. The overall five-year survival rate was 61.3%. A statistically significant difference was found between the survival rates for the 11 cases with histologically proven germinoma and the 13 cases with non-germinoma germ cell tumors, although there was no significant difference between the survival rates for the histologically proven germinomas and the clinically suspected germinomas. Therefore radiation therapy is an effective treatment method for the management of intracranial germ cell tumors.