Treatment outcomes of intracranial germinoma: a retrospective analysis of 170 patients from a single institution.

Purpose: To perform a retrospective analysis of patients with intracranial germinoma treated in our department to evaluate treatment outcomes and determine optimal treatment strategies.

Methods: We reviewed the treatment outcomes of 170 patients with intracranial germinoma who were treated in our department from January 1996 to January 2017. The median patient age was 15 years old. Among the patients, 56 (33%) were pathologically diagnosed, and 114 (67%) were diagnosed clinically. Various radiation fields and doses were used. Cerebrospinal fluid (CSF) and serum beta-human chorionic gonadotropin (β-HCG) levels were examined before treatment in 114 patients. Endocrinological evaluation was performed in 141 patients before and after treatment. A total of 38 patients received chemotherapy prior to radiotherapy (RT). The median follow-up time was 64.5 months (range 4-260.5 months).

Results: The 5- and 10-year overall survival (OS) rates were 94.5% and 91.3%, respectively. The relapse-free survival (RFS) rates at 5- and 10-years were 91.9% and 78.1%, respectively. Relapses occurred in 18 patients within 6 months-10 years. The spinal cord metastasis rate was 3.4% in patients with a localized lesion who did not receive spinal cord irradiation and 16.7% in patients with bifocal disease who were treated using whole ventricular irradiation (WVI) or whole brain radiotherapy (WBRT). Treatment failure did not occur in patients receiving chemoradiotherapy or in patients receiving three-dimensional conformal radiation therapy (3D-CRT)/intensity-modulated radiation therapy (IMRT). The RFS rate did not have a statistically significant correlation with the CSF/serum β-HCG level. After RT, 19.1% of the patients developed newly impaired pituitary function and required hormone replacement therapy.

Conclusions: WVI or WBRT+ primary boost (PB) is a sufficient irradiation field for localized intracranial germinoma, while patients with bifocal disease should undergo craniospinal irradiation (CSI), especially when treated with RT alone. CSF β-HCG is not a prognostic marker for intracranial germinomas. The treatment results of chemotherapy followed by reduced-dose RT are comparable to those of RT alone. IMRT is recommended for intracranial germinoma to improve the target volume accuracy and decrease the complications of RT.