Classification

While there is no staging system for pediatric ALL, there are a number of factors that help determine the best treatment plan and determine the risk that the cancer will come back after treatment. Doctors plan treatment based on these and other factors:

Age when diagnosed. Infants younger than 12 months and children age 10 and older may require more intensive treatments.

White blood cell counts. Children with higher white blood cell counts may require more intensive treatments. Commonly, white blood cell counts are labeled as higher if they are more than 50,000/ml. 

Immunophenotyping. This term refers to the profile of various proteins expressed by the leukemic cells. Knowing if the cancer cells express the proteins more closely resembling those of either normal B-cells or T-cells will help doctors plan appropriate treatment.

Genetic abnormalities in the leukemic cells. Abnormal numbers of chromosomes, abnormal structural changes in a chromosome, or certain molecular genetic changes in the chromosomes of leukemic cells may affect outcome and therefore treatment. Note that the genetic changes referred to here are changes in the genetic material of the leukemic cells, not the child’s cells–most children with leukemia have completely normal genetic material.

Response to early treatment. How the leukemia responds to the first one or two weeks of treatment (determined by examining the child’s blood or bone marrow) may predict the ultimate response to treatment. Recent studies have shown that some children may need more intense treatment to improve the chance of a cure. This includes those whose cancer is not responding well to early treatment or those who have high levels of residual leukemic cells (cells remaining after treatment) at the end of remission induction (see Treatment ).