[Medulloblastoma therapy studies MBL 80 and MED 84 of the Society of Pediatric Oncology and the Société Internationale d'Oncologie Pédiatrique (SIOP)].

In both trials the principle of "sandwich" chemotherapy (administered between surgery and postoperative irradiation) is studied in medulloblastoma. GPO-MBL 80 was essentially a one-arm trial; results after a mean observation period of 3 years show an expected event-free survival rate of 46% at 6 years. "Maintenance" chemotherapy with CCNU and vincristine did not further improve the results. Preliminary results of the joint, prospective, randomised forearm SIOP-GPO trial MED 84 are presented. It is apparently too early to answer any of the two main questions asked by this trial: a) is "sandwich" chemotherapy (as administered) of any value? b) can radiotherapy doses to the supratentorial area and to the spine be moderately reduced in so-called "low risk" patients without compromising long-term results? Thus far, we cannot observe any prognostic influence of the "classical" risk factors as established by other studies.