Intracranial germinoma: Radiation therapy with tumor volume-based dose selection

PURPOSE: To prospectively investigate whether intracranial germinomas, exce pt large ones, can be cured with radiation doses lower than 50 Cy and to de termine 10-year follow-up results. MATERIALS AND METHODS: Between 1985 and 1995, 38 patients with intracranial germinoma diagnosed histologically or with established criteria were enrol led. Total radiation doses to the primary tumor site were 36 Cy after total removal, 40 Cy for tumors less than 2.5 cm in diameter, 45 Cy for those 2. 5-4.0 cm, and 50 Cy for those greater than 4.0 cm, with 1.6-1.8-Gy daily fr actions. Patients underwent irradiation of the primary tumor site or cerebr ospinal axis (20-24 Cry), depending on findings at diagnosis. No chemothera py was allowed. RESULTS: All patients completed radiation therapy. Thirty-five patients wer e treated according to protocol, and three with relatively slow tumor regre ssion or presence of a cyst received additional radiation (5-7 Cy, 50-52 Cy total). Ten-year overall and relapse-free survival rates were 91% and 95%, respectively. Two patients developed meningeal dissemination, but none had local failure. Treatment complications included chordoma in one patient an d internal carotid artery occlusion in another. No treatment-related declin e of performance status was observed in the other patients. CONCLUSION: All tumor volume-based radiation doses were effective, without risk of local failure. Intracranial germinoma 4 cm or less in diameter can be cured with doses of 40-45 Cy. Investigation of further dose reduction se ems worthwhile. Radiation therapy alone with these doses should be compared with ongoing chemotherapeutic protocols plus low-dose (24-30-Cy) irradiati on in future studies.