Chronic Myeloid Leukaemia

What Is CML?

Chronic Myeloid Leukaemia, also called Chronic Myelogenous Leukaeimia (CML) is an uncommon type of cancer of the white blood cells where the bone marrow makes too many white blood cells. It progresses slowly and usually occurs during or after middle age, and rarely occurs in children.

In CML, too many blood stem cells become a type of white blood cell called granulocytes. These granulocytes are abnormal and do not become healthy white blood cells. These are called leukaemia cells, which build up in the blood and bone marrow so there is less room for healthy white blood cells, red blood cells and platelets. And when this happens, infection, anaemia or easy bleeding may occur.

What Are The Symptoms Of CML?

CML has three phases: Chronic, Accelerated, and Blastic. The symptoms depend on the phase of the disease.

CHRONIC PHASE: It is the earlies stage and the easiest to treat. The patient might not even have symptoms.

ACCELERATED PHASE: During this period, the number of abnormal blood cells increases and the possible signs and symptoms are:

• Feeling very tired
• Fever
• Bruises
• Excessive night sweats
• Shortness of breath
• Weight loss
• Pain or fullness below the ribs on the left side (probable sign of an enlarged spleen)
• Pain in the bones

Other symptoms may include stroke, changes in vision, ringing in the ears, a feeling of being in a daze and a prolonged erection.

BLASTIC PHASE: In this phase, the leukaemia cells multiply and crowd out healthy blood cells and platelets. The symptoms are more severe:

• Infections
• Bleeding
• Skin changes including bumps and tumours
• Swollen glands
• Bone pain

What Causes CML?

CML is caused by a genetic change (mutation) in the stem cells produced by the bone marrow. The mutation causes the stem cells to produce too many underdeveloped white blood cells. It also leads to a reduction in the number of other blood cells, such as red blood cells.

The change involves bundles of DNA called chromosomes. Within each stem cell, a section of DNA from one chromosome swaps with a section from another (this change is knowns as the Philadelphia Chromosome).

It’s now known what causes this to happen, but it’s not something that is inherited and it cannot be passed on to children born from parents with the condition.

How Is CML Diagnosed?

Some cases of CML are detected during blood tests carried out for another reason. It is advised that one should visit a doctor or a specialist blood doctor known as a Haematologist, if the symptoms mentioned above persist over time.

While working towards confirming the diagnosis, a general physician will enquire about the various symptoms by asking the following questions:

• What are the problems?
• How long have the symptoms been happening?
• Are the symptoms constant or do they come and go?
• What makes the patient feel better or worse?
• Are there any medications being currently taken?

The doctor may do more tests to confirm the diagnosis, such as:

• Complete Blood Count: Blood test that checks to see how many white blood cells, red blood cells and platelets are present in the blood. A very high level of white blood cells in the blood could be a sign for leukaemia and if detected, the general physician will refer the patient to a Haematologist – specialist doctor who specialises in blood conditions – for further tests.
• Bone Marrow Exam: A Bone Marrow Aspiration and a Bone Marrow Biopsy may be ordered to confirm the diagnosis. It is the only definitive way to confirm the presence of the condition. This will help the haematologist determine the best treatment modality.
• Fish (Flourescence In Situ Hybridisation) Test: This is a detailed lab test of the genes.
• Ultrasound Or CT Scans: This is done to check the size of the spleen.
• Polymerase Chain Reaction Test: This is a lab test that looks for the BCR-ABL gene, which is involved in the process that tells the body to make too many of the wrong kind of white blood cells.

How Is CML Treated?

With modern treatment methods, it’s often possible to control CML for many years, and in a small number of cases, it may be possible to cure it completely. For most people, it’s not possible to eliminate all diseased cells, but treatment can help achieve a long-term remission of the disease.

• Targeted Drugs:Targeted drugs are designed to attack the cancer by focusing on a specific aspect of cancer cells that allows them to grow and multiply. In CML the target of these drugs is the protein produced by the BCR-ABL gene – tyrosine kinase. The targeted drugs that block the action of tyrosine kinase include Imatinib, Dasatinib, Nilotinib, Bosutinib and Ponatinib.
• Blood Stem Cell Transplant: A blood stem cell transplant, also called a bone marrow transplant, offers the ONLY chance for a definitive cure for CML. However, it’s usually reserved for people who haven’t been helped by other treatments.
• Chemotherapy: Chemotherapy drugs are typically combined with other treatments.
• Biological Therapy: These therapies harness the body’s immune system to help fight the cancer.