Radiation therapy for intracranial germinoma: The case for limited volume treatment

Abstract

Although radiation therapy has been universally accepted as the treatment of choice for primary intracranial germinomas, the optimal treatment technique continues to be a matter of controversy. Some authors advocate routine prophylactic craniospinal irradiation for all patients with localized intracranial germinomas whereas others have recommended partial brain fields. A retrospective analysis was performed on all 30 patients with tumors of the pineal and suprasellar regions irradiated at our institution between 1967 and 1987. Definitive histology was obtained in 23 patients. There were 13 germinomas and 10 non-germinomatous germ cell tumors. The 13 patients with biopsy proven germinomas constitute one of the largest modern series and will form the basis of this report. In all 13 patients, the tumor was confined to a single site within either the pineal region (9 patients) or the suprasellar region (4 patients). One patient with a pineal germinoma had CSF cytology positive for malignant cells and this patient was treated with craniospinal irradiation. Twelve patients were treated using partial brain fields encompassing either the tumor plus margin (10 patients) or the entire ventricular system followed by a boost to the primary tumor (2 patients). With the exception of one patient, all patients received a total dose between 4900 and 5500 cGy to the primary (median 5040 cGy). The patient receiving less (3960 cGy) suffered from both local and spine relapse 26 months after diagnosis. The remaining 12 patients were free of disease at 81 months median follow-up time. We suggest that for patients with biopsy proven pineal or suprasellar germinomas, irradiation of partial brain is sufficient and craniospinal irradiation should be administered only to those patients with disease involving more than one intracranial site, demonstrated meningeal seeding, or positive CSF cytology.