Postoperative radiotherapy of childhood medulloblastomas

The purpose of this work is to review the result of radiotherapy in the tre atment of medulloblastoma in pediatric patients. Between 1986 and 1998, 66 children (45 boys and 21 girls) received postoperative irradiation in our i nstitute. Their mean age was 8.29 years. Irradiation was performed by linear accelerator, 36 Gy were applied in the high risk group (partial tumor resection, tumor cell positivity in the liqu or, metastases within the central nervous system) and 30 Gy in the low risk group (total tumor resection, negative liquor cytology, no metastases with in the central nervous system) on the entire cerebrum and spinal cord. This was followed in both groups by the application of 20-20 Gy boost irradiati on on the posterior scala. Studying the survival it has been found that the surgical radicality did no t significantly influence the survival chances of patients, however, with t he increase in the tumor size the survival chance significantly decreases ( p = 0.03). When predicting life expectancy, however, the stage of tumor, th e age of patients, the risk group and the M stage yielded essential informa tion. At the age of 8 years and less, the rate of survivors is 67.6%, for t hose over 8 years is 75.9% (p = 0.21), however the younger age was not sign ificant. The appearance of metastases considerably deteriorates the chances of survival (from 81.5% to 66.7%, p = 0.02). In the low risk group of patients the 5-year survival is 80%, while in the high risk group it is significantly lower, 67.4% (p = 0.04).