Disease Information

Chronic Myeloid Leukaemia (CML) is a Myeloproliferative Disorder (MPD) affecting 1 to 2 people per 100,000 annually. MPDs arise from genetic defects in haematopoietic stem cells, and are associated with an increased production of mature and immature blood cells, which affects one or all cell lineages.

All MPDs share features such as excessive proliferation of blood elements (erythroid precursors, platelet precursors, myeloid precursors) in the bone marrow, peripheral blood and occasionally in extramedullary organs, such as the liver, spleen or lymph nodes.

Chronic Myeloid Leukaemia incidence is relatively consistent in all countries where adequate statistics are available. Occurring at about 1 to 2 per 100,000 populations, CML is a rare disease in children, where it makes up no more than 5% of the leukaemias.

In adults, CML represents about 15% of all cases of leukaemia and is less common than Acute Myeloid Leukaemia, Myelodysplastic Syndrome (AML/MDS), and Chronic Lymphocytic Leukaemia (CLL). The median age of onset is 45 to 55 years. Half of CML patients are older than 60 years.

Aetiology of CML

The aetiology of CML (Chronic Myeloid Leukaemia) is unknown. There is very little evidence linking hereditary factors to CML. The offspring of patients with CML do not have a higher incidence of CML than the general population, and there is no correlation in monozygotic twins. These observations strongly suggest that CML is an acquired (rather than hereditary) disorder.

CML typically progresses through three stages or "phases". Most patients present in chronic phase, progress through an accelerated phase (although some patients skip this phase) and then die after entering a brief phase, blast crisis. The lengths of these phases have been somewhat altered by conventional chemotherapy, but not the clinical course.