Risk groups for childhood ALL

Doctors will consider all the prognostic factors for childhood acute lymphoblastic leukemia (ALL) together to determine a level of risk or risk group. The level of risk includes the likelihood that the cancer will not respond (will be resistant) to treatment or that the cancer will come back (relapse) after treatment.

The level of risk can guide treatment plans for a child with ALL. Doctors use this information to determine if more or less treatment is needed. This ensures that the child is given enough treatment with the least possible side effects.

The following 2 approaches are used to determine the level of risk for childhood ALL.

The National Cancer Institute (NCI)/Rome criteria uses age and white blood cell (WBC) count to determine risk and predict outcome.

Standard-risk ALL must have both of the following criteria:

• The WBC count is less than 50,000 cells/mm³ (50.0 x 10⁹ cells/L).
• The child is 1 to 10 years old.

High-risk ALL can have either of the following criteria:

• The WBC count is greater than 50,000 cells/mm³ (50.0 x 10⁹ cells/L).
• The child is younger than 1 year or older than 10 years.

The Children’s Oncology Group (COG) refines the criteria for risk-based treatment, specifically for B-precursor ALL in children older than one year.

Low-risk ALL must have all of the following criteria:

• The WBC count is less than 50,000 cells/mm³ (50.0 x 10⁹ cells/L).
• The child is 1to 10 years old.
• There are favourable genetics (the child has chromosome and gene abnormalities linked with a favourable prognosis).
• There are no unfavourable genetics (the child has no chromosome or gene abnormalities linked with an unfavourable prognosis).
• There are no blasts in the brain or spinal cord (called the central nervous system, or CNS) and the leukemia hasn’t spread to the testicles.
• The day 29 bone marrow minimal residual disease (MRD) is less than 0.01%.

Average-risk ALL must have all of the following criteria:

• The WBC count is less than 50,000 cells/mm³ (50.0 x 10⁹ cells/L).
• The child is 1to 10 years old.
• There are no unfavourable genetics.
• The day 29 bone marrow MRD is less than 0.01%.
• CNS disease is less than CNS 3 and the leukemia hasn’t spread to the testicles.

High-risk ALL may or may not have favourable genetics, has no unfavourable genetics and has any of the following criteria:

• The WBC count is greater than 50,000 cells/mm³ (50.0 x 10⁹ cells/L).
• The child is 10 years or older but younger than 13 years.
• The day 29 bone marrow MRD is greater than or equal to 0.01%.
• The leukemia has spread to the testicles.

Very high-risk ALL has any of the following criteria:

• The child is older than 13 years.
• There are unfavourable genetics.
• The day 29 bone marrow MRD is greater than or equal to 0.01% and one of the following:
  • There are no favourable genetics.
  • The WBC count is greater than 50,000 cells/mm³ (50.0 x 10⁹ cells/L).
  • The child is older than 9 years.