Chronic Myelogenous Leukaemia: Causes, Symptoms, Risk Factors

Chronic myelogenous leukaemia, or CML, is an uncommon form of bone marrow cancer. Blood cells are made in the spongy bone marrow inside bones. CML is associated with elevated white blood cell numbers in the blood.

When a malignancy is called "chronic" myelogenous leukaemia, it means that it advances more slowly than more severe forms of the illness. The type of cells affected by this cancer is referred to as "myelogenous".

Chronic myelogenous leukaemia is also known as chronic granulocytic leukaemia or chronic myeloid leukaemia. Although it can occur at any age, it primarily affects the elderly and is uncommon in younger people.

Due to advances in treatment, people with chronic myelogenous leukaemia now have a better prognosis. majority of individuals can attain remission and live for many years after diagnosis.

Causes Of Chronic Myelogenous Leukaemia

An acquired genetic mutation or alteration in the myeloid stem cells proliferating in the bone marrow is present in people with CML. Acquired mutations are not inherited and are not present at birth. You can acquire mutations during your lifespan.

Genes that have changed or mutated provide cells with new instructions on what to do in genetic alterations. Here, the mutation results in the creation of the novel fusion gene BCR-ABL. The following series of events is set off by the new gene and results in chronic myeloid leukaemia:

• Myeloid stem cells receive new instructions from the BCR-ABL gene.
• Tyrosine kinase enzymes are produced in an aberrant manner by the stem cells.
• These enzymes aid in controlling cell division. Like "on" and "off" switches, they function.
• The tyrosine kinase enzymes that are abnormal lack an "off" switch.
• Your bone marrow's myeloid stem cells divide and multiply uncontrollably if there is no "off" switch. Your bone marrow's aberrant myeloid stem cells eventually begin to divide and replicate uncontrollably, producing abnormally high numbers of immature white blood cells (blasts). Your bone marrow eventually becomes overpopulated with blasts, which hinders its ability to produce healthy red blood cells, white blood cells, and platelets. Your platelets and aberrant white blood cells may outnumber your red blood cells.

Also Read: Acute Myelogenous Leukaemia: Causes, Symptoms, Risk Factors, Diagnosis and Treatment

Symptoms Of Chronic Myelogenous Leukaemia

Chronic myelogenous leukaemia presents with no symptoms for the most of the time. Blood tests could reveal it.

The following symptoms could appear when they do:

• Bones pain.
• Bleeding easily.
• Feeling full after eating a small amount of food.
• Fatigued.
• High temperature.
• Natural weight loss occuring spontaneously.
• Decrease in appetite.
• Fullness or soreness below the ribs on the left side.
• Sweating excessively as you sleep.
• Visual problems caused by retinal haemorrhage.

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Risk Factors Of Chronic Myelogenous Leukaemia

The following variables raise the chance of developing chronic myelogenous leukaemia:

• Older ages: Compared to toddlers and teenagers, older adults are more likely to have CML.
• Being a man: Compared to women, men have a somewhat higher risk of having CML.
• Radiation exposure: CML has been related to radiation therapy for some forms of cancer.

Chronic myelogenous leukaemia cannot be prevented. There's nothing you could have done to stop it if you get it. A family history does not present as a risk factor. Children do not inherit the gene mutation that causes chronic myelogenous leukaemia from their parents. It is thought that this alteration occurs after birth.

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Diagnosis Of Chronic Myelogenous Leukaemia

The following examinations and techniques are used to diagnose chronic myelogenous leukaemia:

• Physical examination: Your doctor examines you and takes your vital signs, including blood pressure and pulse. Your doctor will also feel for swelling in your belly, spleen, and lymph nodes.
• Blood examinations: For a full blood count, or CBC, the sample is sent to a laboratory. A complete blood count (CBC) counts the various cell types present in the blood. White blood cell counts are frequently extremely high in cases of chronic myelogenous leukaemia. To determine whether anything is malfunctioning, blood tests can also detect organ function.
• Bone marrow examinations: Samples of bone marrow are taken for examination via bone marrow aspiration and bone marrow biopsy. There are liquid and solid parts to bone marrow. A tiny sample of solid tissue is taken with a needle during a bone marrow biopsy. Using a needle, a sample of the fluid is taken during a bone marrow aspiration. The hip bone is usually used to obtain the samples.
• Tests for Philadelphia chromosomal detection: Tests with specialised equipment are used to determine whether bone marrow or blood samples contain the BCR-ABL gene or the Philadelphia chromosome. The polymerase chain reaction test and fluorescence in situ hybridization analysis, or FISH, are two examples of these tests.

Also Read: Williams Syndrome: Causes, Symptoms, Diagnosis, Treatment and Prevention

Stages Of Chronic Myelogenous Leukaemia

In contrast to many other forms of cancer, chronic myeloid leukaemia is not classified by cancer stages by medical professionals. They categorise CML into one of four stages:

• Chronic CML: Being described as "chronic" usually denotes a long-term illness. The phrase "blast percentage" in CML describes the proportion of immature white blood cells, or blasts, in your blood and bone marrow. About 10% of your blood and bone marrow are made up of blasts if you have chronic CML. Ninety to eighty per cent of those with the diagnosis have chronic CML. Not everyone with chronic CML experiences symptoms.
• Accelerated CML: Between 10% and 19% of the cells in your blood or bone marrow are blasts at this phase. Moreover, providers might search for basophils. White blood cells called basophils release enzymes to promote blood flow and avoid blood clots. You may have elevated basophil levels if you have CML.
• Blast CML: Blast CML has the potential to be fatal. Tests for blast CML reveal that at least 20% of the cells in your blood or bone marrow are blasts. The majority of patients with blast phase CML exhibit extremely obvious symptoms, including intense exhaustion, fever, loss of weight, and dyspnea.
• Resistant CML: CML that recurs after therapy or does not improve with treatment is referred to as resistant CML.

Also Read: Megaloblastic Anaemia: Causes, Symptoms, Diagnosis and Treatment

Treatment Of Chronic Myelogenous Leukaemia

Treatment for chronic myelogenous leukaemia aims to eliminate blood cells that carry the BCR-ABL gene. Targeted therapy is often the first step in treatment for most patients and can assist in establishing a long-term remission of the illness.

Targeted therapy

Utilising medications that target particular molecules in cancer cells is known as targeted treatment. Targeted therapy can kill cancer cells by preventing these substances from working. These medications target the tyrosine kinase protein that the BCR-ABL gene produces in cases of chronic myelogenous leukaemia. The medications are referred to as TKIs, or tyrosine kinase inhibitors.

When someone is diagnosed with chronic myelogenous leukaemia, TKIs are the first line of treatment. These targeted medications might cause side effects such as skin oedema or puffiness, nausea, cramping in the muscles, exhaustion, diarrhoea, and skin rashes.

Targeted therapy effectiveness is tracked by blood tests that look for the presence of the BCR-ABL gene. Healthcare professionals may think about using different targeted therapy medications or alternative treatments if the condition doesn't improve or develops resistance to the medication.

The optimal time for patients with chronic myelogenous leukaemia to quit taking targeted medications has not yet been established by medical professionals. Because of this, even when blood tests indicate that the disease is in remission, the majority of patients still take targeted medications. After evaluating the advantages and disadvantages, you and your healthcare practitioner may decide in some cases to discontinue treatment with targeted medications.

Transplantation of bone marrow

For chronic myelogenous leukaemia, a bone marrow transplant, also known as a stem cell transplant, is the only treatment available. But it's often only given to those who have not responded to conventional therapies. This is due to the risks and high incidence of significant consequences associated with bone marrow transplantation.

High doses of chemotherapy drugs are used during a bone marrow transplant in order to destroy the blood-forming cells in your bone marrow. After that, your blood is infused with donor blood stem cells. To replace the sick cells in the blood, the new cells create healthy blood cells.

Chemotherapy

Chemotherapy kills cancer cells using potent medications. Targeted treatment and chemotherapy are occasionally used together to treat aggressive chronic myelogenous leukaemia. The medications you take will determine which side effects you get from chemotherapy.

Clinical examinations

Studies of novel medicines are called clinical trials. The opportunity to test the newest therapies is offered by these studies. Possible negative effects may not be known. Find out from your doctor if you qualify for a clinical trial.

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