Chronic leukaemia

The most common form is chronic myeloid leukaemia and this sheet refers exclusively to this form of leukaemia. It is a form of abnormal cell growth (neoplasia) that originates in immature multipotent blood cells (stem cells) and gives rise to red blood cells, platelets and white blood cells.

It is characterised by cellular proliferation of white blood cells with cytogenetic alteration that consists of the appearance of an abnormal chromosome known as the Philadelphia chromosome. The Philadelphia chromosome is also seen in other processes, such as acute lymphoblastic leukaemia, and diagnostic differentiation is required to distinguish which process is occurring. Chronic myeloid leukaemia may also involve red blood cell and platelet disorders, and is characterised by its chronicity. This disease serves to illustrate the revolution that has taken place in the last few years with targeted therapies in abnormal blood cell growth.

Description

Symptoms

These are not very specific: Usually marked by tiredness, anaemia, loss of appetite.

Who is affected by the condition?

This disease has a low incidence (1-1.5/100,000 pop./yr) and low mortality (more than 90% survival in the last 5 years). It mostly affects middle-aged people (40-50 years), although it can occur at any age.

Diagnosis

A physical examination often reveals spleen growth. Blood tests show a very significant increase in white blood cells and bone marrow aspiration should be conducted to confirm. Genetic and molecular biology tests are also conducted.

Typical treatment

The treatment most used is tyrosine-kinase inhibitors. It is an oral, chronic and relatively well tolerated treatment, including Imatinib: it is the first drug that was described, and the most commonly used. Side effects include submalar skin pigmentation (aesthetic problems), nausea and vomiting, which are often mild.

As there is some resistance to this drug, new drugs need to be developed to stop the other proliferation pathways of the affected cells.