Acute myeloid leukaemia is divided into different groups (subtypes).
There are 2 systems. These are the:
- French-American-British (FAB) system
- World Health Organization (WHO) system
The WHO system is the most common system. The FAB system is rarely used by doctors in the UK and so not included on this page.
Your team plan your treatment according to the particular type of acute myeloid leukaemia you have.
Finding the type of AML
Your doctor looks at your leukaemia cells under a microscope to find out which group your leukaemia is in.
They will do some tests on the leukaemia cells.
This is testing for proteins made by some types of leukaemia cells.
These tests look for chromosome (genetic) changes inside the leukaemia cells.
The World Health Organization (WHO) system
The World Health Organisation (WHO) classification system divides AML into groups according to the type of myeloid cell that has become abnormal and whether:
- there are chromosomal (genetic) changes in the cells
- your leukaemia developed from a blood disorder
- more than one type of blood cell has abnormal changes
- your AML developed after other treatment for cancer
There are different groups, and subtypes within these groups. This system is quite complicated and not covered in detail here. Below are some examples.
In acute myeloid leukaemia, a lump of cells can collect outside the bone marrow. This is called a granulocytic sarcoma. You can get these anywhere in the body.
Acute promyelocytic leukaemia (APL)
Acute promyelocytic Leukaemia is also called AML M3. It is treated quite differently to other types of AML.
Panmyelosis is usually referred to as acute panmyelosis with myelofibrosis (APMF) or acute myelofibrosis. It's a very rare form of AML.
Mixture of AML/ALL
Some leukaemias seem to be a mixture of AML and acute lymphoblastic leukaemia (ALL). The abnormal cells have particular proteins called markers for both ALL and AML. Doctors call these acute biphenotypic leukaemias. Biphenotypic (bye-fee-no-tip-ik) means both types and is extremely rare.
Your consultant or specialist nurse can explain which group you are in and what this means for you.
Doctors also put AML into groups called low risk, intermediate risk, and high risk. This means the risk of your leukaemia coming back (relapse) after treatment. It helps your team plan the best treatment for you.
Risk groups depend on many factors. These include:
- changes in chromosomes (cytogenetic changes)
- gene changes (mutations)
- markers on leukaemia cells
- your white blood cell count when you are diagnosed
- your age at diagnosis
- whether you have a blood disorder (such as myelodysplastic syndrome)
- whether your leukaemia is linked to treatment for an earlier cancer
- whether there are any leukaemia cells in the central nervous system
Your risk group might change as you go through treatment. Your healthcare team can explain your risk group if you’re not sure.
You have a low risk of relapse and you are likely to be cured. Most people with low risk AML have treatment with chemotherapy.
Your risk of relapse falls in between high and low risk. You have chemotherapy and you might have a stem cell transplant.
You have a high risk of relapse. You usually have chemotherapy followed by a stem cell transplant early on in your treatment.