Adjuvant chemotherapy for medulloblastoma: the first multi-centre control trial of the International Society of Paediatric Oncology (SIOP I).

Two hundred and eighty-six patients with medulloblastoma from 46 centres in 15 countries were treated in a prospective randomized trial designed to assess the value of adjuvant chemotherapy. All patients were treated by craniospinal irradiation. Those randomly allocated to receive adjuvant chemotherapy were given vincristine during irradiation and maintenance CCNU and vincristine, given in 6-weekly cycles, for 1 year. The overall survival was 53% at 5 years and 45% at 10 years. At the close of the trial in 1979, the difference between the disease-free survival rate for the chemotherapy and control groups was statistically significant (P = 0.005). Since then, late relapses have occurred in the chemotherapy arm and the statistically significant difference between the two groups has been lost. Although there is now no statistical difference between the two arms of the trial, a benefit for chemotherapy persists in a number of sub-groups; partial or sub-total surgery (P = 0.007), brainstem involvement (P = 0.001), and stage T3 and T4 disease (P = 0.002). A number of prognostic factors for medulloblastoma have emerged; sub-total resection, extent of disease and being male sex carry a poor prognosis.