The challenges of high-dose chemotherapy in CNS tumors.

High-dose, myeloablative chemotherapy with hematopoietic stem cell rescue is used in children and young adults with brain tumors for which conventional therapy is either excessively toxic (e.g., radiotherapy in infants) or ineffective. Thus, the aims of such strategies are to improve both quantity and quality of life. Whether high-dose chemotherapy is less neurotoxic and more effective than other therapeutic approaches is still controversial. We will consider the difficulties in analyzing published data and the challenges of designing effective clinical trials that test high-dose chemotherapy in patients with brain tumors.