Temozolomide in children with recurrent or refractory CNS tumors.

For childen with recurrent or refractory primitive neuro ectodermal tumor (PNET) or high grade glioma of the brain, for whom there is no curative treatment, it is important to preserve quality of life as long as possible without causing significant side effects.
Temozolomide seems to be an interesting drug because it can be administered orally and has little side effects.
Not much information however is available about the administration of this drug in children.
In this protocol two different dose schedules of temozolomide are compared:
- In the standard arm 200 mg/m2/dag is administered 5 days per 28 days.
- In the experimentel arm 150 mg/m2 is administered 2 x 7 dagen (day 0-6 and day 14-20) per 28 days.
Effectivity and side effects are studied. The effectivity is studied by looking at radiological respons after 3 cycles.

Administration of a higher cumulative dose of temozolomide leads to a higher respons rate in patients with recurrent primitive neuro ectodermal tumors and recurrent high grade gliomas of the CNS, while this treatment does not lead to more side effects.

Two different dose schedules of temozolomide are compared:

- In the standard arm 200 mg/m2/dag is administered 5 days per 28 days.

- In the experimental arm 150 mg/m2 is administered 2 x 7 dagen (day 0-6 and day 14-20) per 28 days.