Diencephalic tumors in children: a 30-year experience of a single institution

The purpose of this study is to determine the clinical behavior, treatment modalities, and outcome of different histopathological subgroups of diencephalic tumors in children. Between 1972 and 2002, 150 children with diencephalic central nervous system tumors were retrospectively analyzed. Surgery was used as primary treatment modality if possible. Chemotherapy regimens consisting of lomustine (CCNU), cisplatin + etoposide, cyclophosphamide + vincristine + procarbazine + prednisolone, and bleomycin + etoposide + cisplatin were used since 1972. Radiotherapy was used in high-grade tumors and in low-grade gliomas in the case of residual or recurrent disease. Mean and median values were used for demographic characteristics. Comparison of survival curves for different groups was performed with log-rank analysis. Tumor subtype and chemotherapy regimens were analyzed using Kaplan-Meier method. Age range was 0.1-17 years (median, 7.5 years) with a male to female ratio of 1.1. Low-grade gliomas were 45.3% of the whole group. Optic pathways were the major site of origin (52.7%). Neurofibromatosis type 1 was diagnosed in 19.3%. A hundred and twenty-nine patients were eligible for survival analysis. At 10 years, overall survival (OS) rate was 74.6%, and the event-free survival (EFS) rate was 43.5% in the whole group. The OS and EFS rates of low-grade glial tumors at 10 years were 98% and 52.8%, respectively. The majority of the cases were low-grade gliomas in the diencephalon. The prognosis of the tumors extended in the diencephalon, thalamus, and pineal region was worse than the tumors at optic pathways and hypothalamus.