Acute lymphoblastic leukemia: Risk categories

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Learn how acute lymphoblastic leukemia (ALL) is classified into different risk categories.

Key points

  • Acute lymphoblastic leukemia (ALL) can be considered standard risk, high-risk, or very high-risk.
  • Your child's age, initial white blood cell count, presence of leukemic cells inside the CNS, ALL subtype, chromosome changes in leukemic cells, leukemic cells in testes and response to induction therapy at day 29 will determine their risk category and appropriate treatment.

Some types of leukemia are easier to treat than others. This depends on a variety of different factors which classify your child’s acute lymphoblastic leukemia (ALL) into a certain risk category: standard risk, high-risk, or very high-risk.

Knowing the risk group of your child’s illness helps doctors design the most effective treatment for your child.

Factors influencing each risk group

Several different features will influence your child’s ALL risk group and treatment. These include:

  • initial white blood cell count
  • age of your child
  • if, and how many, leukemic cells are inside the central nervous system. This includes the cerebrospinal fluid (CSF) which is the fluid that surrounds the brain and spinal cord.
  • ALL subtype (B-cell or T-cell)
  • chromosome changes inside leukemic cells.
  • if leukemic cells are present in the testes
  • response to induction therapy as indicated by the MRD at day 29

ALL risk groups

Standard-risk ALL

Your child is considered standard-risk if they have all of the following features:

  • they are between age 1 and 10
  • they have less than 50,000 white blood cells per cubic millimetre (mm3) of blood when they are diagnosed
  • No blasts in the CSF (CNS 1) or less than 5 blasts in CSF (CNS 2)
  • no testicular leukemia
  • no unfavorable cytogenetic features
  • no steroids were given before diagnosis of leukemia
  • a good response to the first phase of chemotherapy (induction), as measured by a bone marrow test on day 29 with MRD.

High-risk ALL

Your child is considered high risk if they have any of the following features:

  • less than age one or older than ten years of age
  • more than 50,000 white blood cells/mm3 of blood when they are diagnosed
  • More than 5 leukemic cells in the CSF (CNS 3)
  • leukemia cells with chromosome changes that are more difficult to treat
  • testicular involvement
  • steroids given before diagnosis of leukemia.

Very high-risk ALL

Children are considered to have very high-risk ALL based on certain chromosome changes inside their leukemia cells that make it harder to treat. They may require other special types of medication.

Last updated: March 6th 2018