[The role of radiotherapy in the prevention of recurrence and central nervous system metastases in childhood medulloblastoma].

PURPOSE: To present the postoperative radiotherapy technique in children with medulloblastoma, and analyse the effectiveness of radiotherapy and the survival data. MATERIALS AND METHODS: 66 consecutive children (45 male and 21 female) received postoperative chemotherapy and radiotherapy between 1986 and 1998. The mean age was 8.3 years. The radiotherapy was performed with linear accelerator 9MV X-ray irradiation. The high risk patients received 36 Gy craniospinal irradiation, the low risk patients recived 30 Gy. The boost irradiation to the posterior fossa was 20 Gy in both patient groups. The patients received multi-drug chemotherapy immediately after the tumor resection. The radiotherapy started 6-8 weeks after the operation. RESULTS: All 66 patients were evaluated. The mean follow-up time was 45.4 months. The chance of cure is higher at age 8 or more, and less favorable under age 8. After 60 months 68.6% of children under age 8 and 75.9% older than 8 are alive. 20 children (64.5%) are alive after radical tumorectomy and 11 died. The 5 year overall survival was 71%. Recurrence was observed in 23/66 cases, it was the most frequent cause of death. Local failure was in posterior fossa in 15 patients (68.2%). CONCLUSION: The radicality of operation had no significant influence to the overall survival. The tumor stage, age of patients, risk group and metastases are important prognostic factors.