Chemotherapy for ALL is typically divided into three phases:
- Induction
- Consolidation
- Maintenance
The goal of the induction phase is to induce a remission, a state in which there is no visible evidence of disease and blood counts are normal. In the consolidation phase, patients may receive high doses of chemotherapy, which are designed to eliminate any remaining leukemic cells. During the maintenance phase, patients may receive lower doses of drugs but for long periods of time -- up to two years. The goal of this phase is to destroy any stray leukemia cells that have evaded the agents used in the remission induction and consolidation stages.
Chemotherapy for CNS Involvement
Sometimes ALL can spread to the central nervous system (CNS) -- the brain and the spinal cord. Treatment to prevent or control CNS involvement is included in most patients' treatment regimens. To prevent spread of the disease to the CNS, physicians may administer chemotherapy intrathecally -- directly through the spinal column into the fluid that bathes the spinal cord and brain. Alternatively, patients may receive high-dose systemic chemotherapy or radiation therapy to prevent the spread of disease to the CNS.
