Chronic myeloid leukemia


Chronic myeloid leukemia (CML) is a cancer of the white blood cells. It is a form of leukemia characterized by the increased and unregulated growth of predominantly myeloid cells in the bone marrow and the accumulation of these cells in the blood. CML is a clonal bone marrow stem cell disorder in which proliferation of mature granulocytes (neutrophils, eosinophils, and basophils) and their precursors is the main feature. It is a type of myeloproliferative disease associated with a characteristic chromosomal translocation called the Philadelphia chromosome.

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    Cause & Symptoms
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    Diagnosis & Therapy

Diagnosis

The disease is often discovered by chance during a routine blood test when it is noticed that there is an overproduction of white blood cells. A normal leukocyte count measures up to 10,000/µl but with CML, the leukocyte count can go beyond 500,000/µl.

Blood tests

The blood cells are counted and examined using a so-called peripheral blood image. If the leukocyte count is excessively high, it is important that further cytochemical testing of the blood is carried out. This includes measuring the activity of the alkaline leukocyte phosphates (ALP). If CML is present then the ALP level will be low.  

Bone marrow puncture

Further indications of the presence of CML are found by extracting tissue samples from the bone marrow. Tissue samples usually consist of bone marrow fluid and small tissue cylinders from either the iliac crest region or the sternum which, after extraction, are then subjected to histological examination.
In more than 90% of cases, a typical chromosome change (the Philadelphia chromosome equivalent to a shortened chromosome 22) can be found in white blood cells.

Ultrasound scan

It is very important that the organs in the upper abdomen undergo an ultrasound scan and that special attention is paid to the size of the spleen. The size of the spleen can usually give an indication of how far the disease has progressed.

Therapy

Over the past 10 years the treatment of CML has made significant progress. Due to the complexity of the disease however, treatment needs to be carried out in close cooperation with hematology centers.

It is important that treatment is started as early as possible, preferably right after a confirmed diagnosis since it is difficult to treat CML in its more advanced stages.

Drug treatment and stem cell transplantation

Since 2001, targeted treatment using imatinib (a tyrosin kinase inhibitor) hast been used successfully alongside standard drugs such as hydroxyurea and interferon alpha.

A stem cell transplant is currently the only form of treatment that may cure CML. However, due to the high risk of complications that may arise, a thorough consideration of the risks and benefits needs to be made.

It is important that each individual discusses their choice of therapy or the combination of different treatment options with the hematologist in charge.

Participation in a clinical studies

As is the case for all other hematological and oncological diseases, participation in clinical studies is of benefit to the patients. Clinical studies not only enable the development of future treatments, but they also ensure the best possible quality assurance (treatment per protocol) and documentation for participating individuals.