Classification for Childhood Acute Lymphoblastic leukaemia

Executive Summary

Unlike other types of cancer, there is no staging system for childhood acute lymphoblastic leukaemia. Doctors plan the child’s treatment based on these and other factors involving age (infants younger than 12 months and children age ten and older), white blood cell counts (children with very high white blood cell counts need intensive treatments), genetic abnormalities in the leukaemia cells, response to early treatment, and immunophenotyping.

Classification of Childhood Acute Lymphoblastic leukaemia

There is no staging system for childhood Acute lymphoblastic leukaemia, unlike other types of cancer. However, several factors help doctors choose the best treatment plan and predict the disease’s chance to return after treatment. Doctors plan the child’s treatment based on these and other factors-

  • Age – Infants younger than 12 months and children age ten and older need more intensive treatments.
  • White blood cell counts – Children with very high white blood cell counts need more intensive treatments. Commonly, white blood cell counts are labelled as very high if they are more than 50,000 per microliter (microL). 
  • Genetic abnormalities in the leukaemia cells – Abnormal numbers of chromosomes, abnormal structural changes in a chromosome, or specific molecular genetic changes in the chromosomes of leukaemia cells may affect outcome and treatment ​1​. It is noteworthy that the genetic changes referred to here are changes in the genes of the leukaemia cells; not all the cells in a child’s body – most children with leukaemia have completely normal genes. 
  • Response to early treatment – How well the treatment works in the first 1 to 4 weeks may predict leukaemia’s overall response to treatment. This will be determined by regularly examining the child’s blood or bone marrow. Recent studies showed that some children might need more intense treatment to enhance the chance of a cure. This involves children whose cancer is not responding well to the first treatments or those having high levels of residual leukaemia cells (cells remaining after treatment) at the end of the treatment period called remission induction. 

Immunophenotyping – This test shows the types and amounts of proteins made or expressed by the leukaemia cells. Knowing if the cancer cells express the proteins similar to normal white blood cells called T-cells or B-cells will help doctors plan appropriate treatment ​2​. It is also helpful to help predict how well treatment will work.

References

  1. 1.
    Ross ME, Zhou X, Song G, et al. Classification of pediatric acute lymphoblastic leukemia by gene expression profiling. Blood. Published online October 15, 2003:2951-2959. doi:10.1182/blood-2003-01-0338
  2. 2.
    Nakazawa S, Saito M, Okazaki T, et al. Immunological Classification of Childhood Acute Lymphoblastic Leukemia. Pediatr Int. Published online August 1991:507-521. doi:10.1111/j.1442-200x.1991.tb02580.x