Chronic myelogenous leukemia (CML)

What is chronic myelogenous leukaemia (CML)?

Chronic myelogenous leukaemia (CML) is a rare type of bone marrow cancer that affects the spongy tissue inside bones that produces blood cells. The number of white blood cells in the blood increases as a result of CML.

The name “chronic” refers to the fact that chronic myelogenous leukaemia progresses more slowly than acute forms of leukaemia. In chronic myelogenous leukaemia, the term “myelogenous” (my-uh-LOHJ-uh-nus) refers to the type of cells afflicted by the cancer.

Chronic myeloid leukaemia and chronic granulocytic leukaemia are other names for chronic myelogenous leukaemia. It mostly affects older persons and rather rarely affects youngsters, while it can strike anyone at any age.

People with chronic myelogenous leukaemia now have a much better prognosis thanks to advances in treatment. After diagnosis, the majority of persons will go into remission and survive for many years.

What is CML ?

Chronic myelogenous leukaemia (also known as CML or chronic granulocytic leukaemia) is a slow-progressing blood and bone marrow disease that mainly strikes people in their forties or fifties, with children being the exception.

1. Chronic myelogenous leukaemia is a condition in which the bone marrow produces an abnormally large number of white blood cells.
2. Red blood cells, white blood cells, and platelets can all be affected by leukaemia.
3. Weight loss and exhaustion are two signs and symptoms of chronic myelogenous leukaemia.
4. The Philadelphia chromosomal mutation (change) is found in the majority of CML patients.
5. The diagnosis of chronic myelogenous leukaemia is made using blood and bone marrow tests.
6. The prognosis (probability of recovery) and treatment options are influenced by a number of factors.

Symptoms of CML

Symptoms and indications of chronic myelogenous leukaemia are not always present. It’s possible that it’ll be discovered via a blood test.

When they occur, the following signs and symptoms may appear:

1. Bone ache
2. Easy to bleed
3. After eating a tiny amount of food, you feel satisfied.
4. Fever
5. Weight loss without exerting effort
6. Appetite loss.

Causes of CML

When something goes wrong in the genes of your bone marrow cells, chronic myelogenous leukaemia develops. It’s unclear what triggers this process, but doctors have figured out how it leads to chronic myelogenous leukaemia.

Abnormal chromosome

Human cells have 23 pairs of chromosomes by default. These chromosomes contain DNA, which includes the instructions (genes) that control your body’s cells. The chromosomes in blood cells swap parts with one other in persons with chronic myelogenous leukaemia. An extra-short chromosome 22 and an extra-long chromosome 9 are formed when a portion of chromosome 9 swaps places with a section of chromosome 22.

The Philadelphia chromosome, which is extra-short chromosome 22, is named after the city where it was discovered. 90% of persons with chronic myelogenous leukaemia have the Philadelphia chromosome in their blood cells.

A new gene is created by the Philadelphia chromosome. A new gene termed BCR-ABL is formed when genes from chromosome 9 interact with genes from chromosome 22. The BCR-ABL gene includes instructions telling the aberrant blood cell to make too much tyrosine kinase protein. Tyrosine kinase promotes cancer by permitting uncontrolled growth of specific blood cells.

The bone marrow, a spongy material inside your bones, is where your blood cells begin. Your bone marrow creates immature cells (blood stem cells) in a controlled manner when it functions normally. These cells subsequently mature and specialise into the red, white, and platelet blood cells that circulate throughout your body.

This mechanism is disrupted in chronic myelogenous leukaemia. The BCR-ABL gene causes a tyrosine kinase that allows too many white blood cells to develop. The Philadelphia chromosome is aberrant in most or all of these cells. Normal white blood cells develop and die, while sick white blood cells do not. Diseased white blood cells multiply rapidly, pushing out healthy blood cells and causing bone marrow damage.

Diagnosis of CML

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

Physical examination: Your doctor will examine you and take your vital signs, including your pulse and blood pressure. He will also examine your lymph nodes, spleen, and abdomen to see if they are enlarged.

Blood test: A complete blood count might detect irregularities in your blood cells, such as an abnormally high number of white blood cells. Blood chemistry tests used to assess organ function may reveal anomalies that can aid your doctor in making a diagnosis.

Bone marrow test: Bone marrow samples are collected for laboratory testing using bone marrow biopsy and bone marrow aspiration. Bone marrow from your hipbone is collected for these examinations.

Look for the Philadelphia chromosome with these tests. Blood or bone marrow samples are analysed for the presence of the Philadelphia chromosome or the BCR-ABL gene using specialised tests such as fluorescence in situ hybridization (FISH) analysis and the polymerase chain reaction (PCR) test.

Treatment of CML

• There are different types of treatment for patients with chronic myelogenous leukemia.
• Six types of standard treatment are used:
  • Targeted therapy
  • Chemotherapy
  • Immunotherapy
  • High-dose chemotherapy with stem cell transplant
  • Donor lymphocyte infusion (DLI)
  • Surgery
• New types of treatment are being tested in clinical trials.

Targeted drug therapy

Targeted medications target a specific component of cancer cells that causes them to thrive and multiply in order to combat the disease. The protein generated by the BCR-ABL gene, tyrosine kinase, is the target of these medications in chronic myelogenous leukaemia.

Targeted drugs that block the action of tyrosine kinase include:

• Imatinib (Gleevec)
• Dasatinib (Sprycel)
• Nilotinib (Tasigna)
• Bosutinib (Bosulif)
• Ponatinib (Iclusig)

For those with chronic myelogenous leukaemia, targeted medicines are the first line of treatment. Swelling or puffiness of the skin, nausea, muscle cramps, exhaustion, diarrhoea, and skin rashes are among side effects of these targeted medications.

The success of targeted medication therapy is monitored using blood tests that detect the presence of the BCR-ABL gene. Doctors may investigate alternative targeted medications, such as omacetaxine (Synribo), or other treatments if the disease does not respond or grows resistant to targeted therapy.

Doctors have yet to decide whether it is safe to cease taking targeted medications for persons with chronic myelogenous leukaemia. As a result, even when blood tests show that the disease is in remission, most people continue to take targeted medications. After weighing the benefits and hazards, you and your doctor may decide to discontinue treatment with targeted medications in specific circumstances.

Bone marrow transplant

A bone marrow transplant, also known as a stem cell transplant, is the only way to cure chronic myelogenous leukaemia permanently. However, because bone marrow transplants are risky and have a high probability of significant consequences, it’s normally reserved for those who haven’t responded to other treatments.

High doses of chemotherapy medications are used to kill the blood-forming cells in your bone marrow after a bone marrow transplant. After that, a donor’s blood stem cells are pumped into your bloodstream. To replace the sick cells, the new cells generate new, healthy blood cells.

Chemotherapy

Chemotherapy is a medication treatment for leukaemia that kills fast-growing cells in the body. To treat aggressive chronic myelogenous leukaemia, chemotherapy medicines are occasionally coupled with targeted medication therapy. Chemotherapy medications have different side effects depending on which ones you take.

Clinical trials

Clinical trials look at the most up-to-date therapies for diseases as well as innovative ways to use old ones. Enrolling in a clinical trial for chronic myelogenous leukaemia may provide you with the opportunity to attempt the most cutting-edge treatment, but it does not guarantee a cure. Find out what clinical trials are available to you by speaking with your doctor. You can explore the advantages and disadvantages of a clinical trial together.