STAGING, SCORING AND GRADING OF MEDULLOBLASTOMA A POSTOPERATIVE PROGNOSIS PREDICTING SYSTEM BASED ON THE CASES OF A SINGLE INSTITUTE

Although recently survival of some medulloblastoma patients increased remarcably, it remains a serious diagnosis in others. In order to pred ict the postoperative prognosis in patients treated for medulloblastom a, a new staging, scoring and grading system was developed. Sixty-six patients operated on microsurgically between 1975 and 1990 at a single neurosurgical center were fully followed-up. No patient was excluded due to a poor postoperative course. Completion of commonly used radiot herapy protocols was attempted in all patients. Survival of patients w as evaluated by the Kaplan-Meier method. The following 5 parameters we re selected to define subgroups. patients' age, tumour location and hi stology, degree of resection and presence or absence of metastases. Pa tients older than 10 years had a better prognosis than individuals age d 10 or less (p < 0.01), patients with lateral tumours had a better pr ognosis than patients with midline tumours with brain stem infiltratio n (p < 0.05), patients with complete tumour resection had a more favou rable prognosis than individuals with subtotal (p < 0.01) or partial r esection (p < 0.001), patients without metastases at the time of diagn osis had a better prognosis than individuals without such evidence (p < 0.001), patients with the desmoplastic tumour variant had a better p rognosis than patients with classical tumour histology (p < 0.01). Acc ording to the prognosis of a distinct subgroup, scoring points were di stributed which correlated with the degree of inter-subgroup significa nces. The sum of a single patient's scoring points was called the tota l score, Based on this score, three groups of prognosis were distingui shed. The good prognosis group (n = 29) showed a significantly better survival (p < 0.05) than the moderate prognosis group (n = 26), wherea s the moderate prognosis group had a significantly better survival (p < 0.05) than the poor prognosis group (n = 11). A Kaplan-Meier surviva l rate of 62% was found in patients of the good prognosis group, a rat e of 22% in the moderate prognosis group, and a rate of 0% in the poor prognosis group. It is concluded that this new staging, scoring and g rading system is a simple and recommendable prognostic system for all patients treated surgically for medulloblastoma.