Combination Chemotherapy Followed by Peripheral Stem Cell Transplantation or Bone Marrow Transplantation in Treating Patients With Brain Cancer

RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Peripheral stem cell transplantation or bone marrow transplantation may allow the doctor to give higher doses of chemotherapy drugs and kill more tumor cells. PURPOSE: Phase I trial to study the effectiveness of combining temozolomide, thiotepa, and carboplatin followed by peripheral stem cell transplantation or bone marrow transplantation in treating patients who have brain cancer.