BACKGROUND: The purpose of this study was to evaluate a reduced irradiation dose strategy for newly diagnosed primary central nervous system (CNS) germinomas. METHODS: Twenty patients with histologically diagnosed localized pure germinoma (n = 19) or germinoma with a mature teratoma component (n = 1) received four cycles of carboplatin and etoposide at 3-week intervals. In 18 patients, chemotherapy was followed by whole ventricular irradiation to 21.6-25.5 Gy with a simultaneous integrated or sequential primary site boost to 30-30.6 Gy. Initial tumor markers for beta-human chorionic gonadotrophin (HCGbeta) and alpha-fetoprotein (AFP) were evaluated in serum and lumbar cerebrospinal fluid (CSF). Endoscopic biopsies were performed in 12 patients and partial resections in the remaining 8 patients at diagnosis. Neurocognitive function was evaluated periodically following treatment. RESULTS: Eighteen of 20 patients are without evidence of residual or recurrent tumor. Both relapsing patients were subsequently determined to harbor malignant non-germinomatous germ cell tumor (NGGCT). This retrospective study shows that the Kaplan-Meier estimates of event-free survival (EFS) and overall survival (OS) at 3 years for all 20 patients were 89.5 +/- 7.1% and 100%, respectively. Neurocognitive function was well preserved in all 19 evaluable patients. CONCLUSION: Chemotherapy followed by reduced dose whole ventricular and local boost irradiation appears to be effective in patients with localized pure CNS germinoma with evidence of preservation of neurocognitive function.