Chronic Myeloid Leukaemia (CML)
Chronic Myeloid Leukaemia (or CML) is a blood cancer that causes the bone marrow to produce excessive numbers of granulocytes (a type of white blood cell). It is categorized within the Chronic Myeloproliferative Syndromes.
Under normal conditions, the stem cells of the bone marrow mature until they are converted into different types of blood cell. CML causes an alteration in the stem cells which is transmitted into all areas of the blood, but the granulocytes are the most affected. The granulocytes are produced at uncontrollable rate, invading the bone marrow and the rest of the organism, impeding the normal production of the rest of the blood cells and altering the function of varying organs.
Chronic Myeloid Leukaemia develops in three phases: the initial stage or chronic phase, is characterized by the excessive production of granulocytes that are easily controlled; the second phases or acceleration, is the point where the production of granulocytes becomes more difficult to control; the third stage or blastic phase, sees the transformation into acute leukaemia.
CML predominantly affects adults (the average age is 50 years old) and is rare among children. Each year the number of new cases is around 15 per million inhabitants.
Xavier, CML patient with his wife, Dolors and their son. Read Xavier's case.
Main Symptoms
In 60 % of cases, the disease is diagnosed after a routine checkup. Patients can remain completely without symptoms for many years. For other patients the symptoms can be: weakness, persistent fatigue, fever, sweating, weight loss, anaemia, hemorrhages, easy bruising, small infections, pain in the bones and joints. Many patients also suffer an irritation in the left side of the abdomen as a consequence of the growth of the spleen. All of these symptoms can easily be brought under control once the patient receives treatment and the patient can thereafter remain symptomless until the disease progresses to a more aggressive stage.
Study
The diagnosis of CML is based on the growth of the number of granulocytes in the blood and the bone marrow. In addition, the diagnosis is determined by the alteration of the characteristics in the blood cell chromosomes called Philadelphia Chromosome and the genetic alteration that causes the disease, called bcr/abl gene. In order to reach the diagnosis it is necessary to closely examine the blood and the bone marrow. The bone marrow can be analysed by conducting a puncture of the sternum or the hip bone. Finally, a bone marrow biopsy should be carried out (obtained by taking a small cylindrical sample from the hip bone) to study the structure of the bone marrow.
Treatment
The treatment will depend on the particular phase of the disease and the age of the patient.
Due to their extraordinary effectiveness Tyrosine-kinase inhibitors (TKI) have developed into the primary treatment method over the last couple of years. Patients who have high initial leukocyte figures are normally administered Hydroxyurea for several days in order to reduce the level; they can begin TKI treatment once these numbers are under control. The most commonly applied TKI is imatinib (Glivec®), but two other forms exist for patients who do not respond well to imatinib called, dasatinib (Sprycell®) and nilotinib (Tasigna®).
These agents completely control the disease in 90% of cases and this treatment can be maintained for many years, with regular molecular responses (the reduction of the bcr/abl levels). Despite the fact these agents do not find a definitive cure for CML, their effectiveness and minimal toxicity of these agents has meant that they have completely replaced an allogeneic bone marrow transplant as the first response to CML
Although a transplant leads to the cure of the disease in 50-70% of cases, this process is associated with considerable morbidity and mortality. For that reason it is reserved for patients in the advanced stages of the disease or patients who are not responding well to the TKI treatement.
The siblings of patients younger than 60-65 who find themselves in this situation will be assessed for compatibility. In the eventuality that there is no compatible family member, a search will be launched by the José Carreras International Foundation to find compatible donor.
Read the story of a CML patient: "Two Great Rewards".
For more information, you can consult the following webpages:
• National Cancer Institute
• Fundación Leucemia y Linfoma
• Médica Medline Plus Encyclopedia
• The Leukaemia & Lymphoma Society
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