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Childhood Acute Lymphoblastic Leukemia Treatment (PDQ®): Treatment - Health Professional Information [NCI] - CNS-Directed Therapy for Childhood ALL

Successful treatment of children with acute lymphoblastic leukemia (ALL) requires the control of systemic disease (e.g., marrow, liver and spleen, lymph nodes), and the prevention or treatment of extramedullary disease, particularly in the central nervous system (CNS).

Approximately 3% of patients have detectable CNS involvement by conventional criteria at diagnosis (cerebrospinal fluid [CSF] specimen with ≥5 white blood cell [WBC]/μL with lymphoblasts and/or the presence of cranial nerve palsies). However, unless specific therapy is directed toward the CNS, the majority of children will eventually develop overt CNS leukemia. Therefore, all children with ALL should receive systemic combination chemotherapy together with some form of CNS prophylaxis.

Historically, survival rates for children with ALL did not improve until CNS-directed therapy was instituted. The early institution of adequate CNS therapy is critical for eliminating clinically evident CNS disease at diagnosis and for preventing CNS relapse in all patients. Standard treatment options for CNS-directed therapy include the following:

  1. Intrathecal chemotherapy.
  2. CNS-penetrant systemic chemotherapy.
  3. Cranial radiation.

The type of CNS-therapy that is used is based on a patient's risk of CNS-relapse, with higher-risk patients receiving more intensive treatments. Data suggest that the following groups of patients are at increased risk of CNS relapse:

  • Patients with blasts in the CSF but fewer than 5 WBC/µL (CNS2) are at increased risk of CNS relapse,[1] although this risk appears to be nearly fully abrogated if they receive more intensive intrathecal chemotherapy, especially during the induction phase.[2]
  • Patients who have a traumatic lumbar puncture showing blasts at the time of diagnosis have an increased risk of CNS relapse, and these patients receive more intensive CNS-directed therapy on some treatment protocols.[2,3]

CNS-directed treatment regimens for newly diagnosed childhood ALL are presented in Table 2:

Table 2. CNS-Directed Treatment Regimens for Newly Diagnosed Childhood ALL

Disease StatusStandard Treatment Options
ALL = acute lymphoblastic leukemia; CNS = central nervous system; CNS3 = cerebrospinal fluid with 5 or more white blood cells/µL and cytospin positive for blasts.
Standard-risk ALLIntrathecal chemotherapy
 Methotrexate alone
 Methotrexate with cytarabine and hydrocortisone
CNS-penetrant systemic chemotherapy
 High-dose methotrexate with leucovorin rescue
High-risk ALLIntrathecal chemotherapy
 Methotrexate alone
 Methotrexate with cytarabine and hydrocortisone
CNS-penetrant systemic chemotherapy
 High-dose methotrexate with leucovorin rescue
Cranial radiation

A major goal of current ALL clinical trials is to provide effective CNS therapy while minimizing neurologic toxic effects and other late effects.

Intrathecal Chemotherapy

All therapeutic regimens for childhood ALL include intrathecal chemotherapy. Intrathecal chemotherapy is usually started at the beginning of induction, intensified during consolidation (four to eight doses of intrathecal chemotherapy given every 2–3 weeks), and, in certain protocols, continued throughout the maintenance phase.

Intrathecal chemotherapy typically consists of one of the following:[4]

  1. Methotrexate alone.
  2. Methotrexate with cytarabine and hydrocortisone.

WebMD Public Information from the National Cancer Institute

Last Updated: February 25, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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