Chronic Myelogenous Leukemia


A rare kind of cancer of the bone marrow, the spongy tissue found inside bones where blood cells are formed, is chronic myelogenous leukemia (CML). The amount of white blood cells in the blood rises as a result of CML.

In contrast to acute types of leukemia, which tend to advance more quickly, chronic myelogenous leukemia tends to advance more slowly. In chronic myelogenous leukemia, the word "myelogenous" refers to the type of cells that are impacted by this malignancy.

Other names for chronic myelogenous leukemia include chronic granulocytic leukemia and chronic myeloid leukemia. Though it can happen to anybody at any age, it mainly affects elderly individuals and happens very infrequently in children.

A much better prognosis has been achieved for those with chronic myelogenous leukemia as a result of therapy advancements. After diagnosis, the majority of patients will have remission and live a long time.

Chronic Myelogenous Leukemia: Causes

When your bone marrow cells' genes are altered, chronic myelogenous leukemia can develop. The cause of this process is unknown, but researchers have learned how it develops into chronic myelogenous leukemia.

An Aberrant Chromosome Develops

There are typically 23 pairs of chromosomes in human cells. The DNA that holds the instructions (genes) that regulate the cells in your body is stored on these chromosomes. When a person has chronic myelogenous leukemia, their blood cells' chromosomes switch portions with one another. An extra-short chromosome 22 and an extra-long chromosome 9 are created when a portion of chromosome 9 swaps places with a segment of chromosome 22.

Ninety percent of patients with chronic myelogenous leukemia have Philadelphia chromosomes in their blood cells.

A novel gene is produced by the aberrant chromosome

A new gene is made thanks to the Philadelphia chromosome. A new gene termed BCR-ABL is produced when genes from chromosomes 9 and 22 come together. Tyrosine kinase, a protein, is produced in excess by the aberrant blood cell as a result of instructions in the BCR-ABL gene. Tyrosine kinase causes some blood cells to expand out of control, which aids in the development of cancer.

The novel gene permits an excessive number of sick blood cells

The spongy substance inside your bones called bone marrow is where your blood cells are created. Your bone marrow creates immature cells (blood stem cells) in a regulated manner when it is operating correctly.

These cells subsequently develop into the different red, white, and platelet blood cell types that circulate throughout your body.

This procedure is flawed in chronic myelogenous leukemia. The BCR-ABL gene's tyrosine kinase promotes the development of an excessive number of white blood cells. The defective Philadelphia chromosome is present in the majority or all of these cells. The sick white blood cells don't develop and degrade as healthy ones do. Massive accumulations of the sick white blood cells squeeze out good blood cells and harm the bone marrow.

Chronic Myelogenous Leukemia: Symptoms

The symptoms of chronic myelogenous leukemia are frequently absent. During a blood test, it could be found.

Signs and symptoms of their occurrence may include −

  • A bone ache

  • Simple bleeding

  • Experiencing satiety after a little meal

  • Feeling exhausted or run-down Fever

  • Loss of weight without effort

  • Reduced appetite

  • The left side's pain or swelling below the ribs

  • Excessive perspiration as you sleep (night sweats)

Chronic Myelogenous Leukemia: Risk Factors

The major risk factors include −

  • Old age

  • Being a man

  • Radiation exposure, such as that used in several cancer treatments

  • Family history does not pose a concern.

Parents can’t pass on the mutation that causes chronic myelogenous leukemia to their offspring. It is thought that this mutation is acquired, meaning it appears after birth.

Chronic Myelogenous Leukemia: Diagnosis

To diagnose chronic myelogenous leukemia, your doctor may suggest the following tests −

  • Exam of the body. Your doctor will examine you and take your blood pressure and pulse, among other vital indicators. To evaluate whether your lymph nodes, spleen, or belly are swollen, he or she will also feel those organs.

  • A blood test. Your blood cells may be aberrant, as seen by a very high white blood cell count, according to a complete blood count. Blood chemistry tests to assess organ function may also detect anomalies that aid in the diagnosis by your doctor.

  • Test on the bone marrow. To obtain bone marrow samples for laboratory testing, two procedures are used: bone marrow biopsy and bone marrow aspiration. For these examinations, hipbone bone marrow is extracted.

  • Examinations to seek for the Philadelphia chromosome. To determine if the Philadelphia chromosome or the BCR-ABL gene is present in blood or bone marrow samples, specialized procedures like the fluorescence in situ hybridization (FISH) analysis and the polymerase chain reaction (PCR) test are used.

Chronic Myelogenous Leukemia: Treatment

Treatment for chronic myelogenous leukemia is to eradicate blood cells that carry the faulty BCR-ABL gene, which is the source of the excess number of sick blood cells. Most patients start their course of therapy with certain medications that might lead to a long-term remission of their illness.

Certain Medication Treatment

To combat cancer, targeted medications target a particular feature of cancer cells that promotes their growth and multiplication. These medications target tyrosine kinase, a protein produced by the BCR-ABL gene, in chronic myelogenous leukemia.

Targeted medications that prevent tyrosine kinase activity include −

  • Imatinib

  • Dasatinib

  • Nilotinib

  • Ponatinib with Bosutinib

The first line of treatment for those with chronic myelogenous leukemia is targeted medication.

The only option for permanent recovery from chronic myelogenous leukemia is a bone marrow transplant, commonly known as a stem cell transplant. Nevertheless, because bone marrow transplants are risky and have a high probability of significant consequences, they are often only used for patients who haven't responded to previous therapies.

Chronic Myelogenous Leukemia: Prevention

The majority of instances of chronic myeloid leukemia cannot be prevented, at this time (CML). Making lifestyle adjustments and eliminating certain risk factors can help prevent some types of cancer, but for the majority of CML cases, this is not the case.

Conclusion

Adults frequently develop CML, leukemia that has a fair prognosis because of the development of tyrosine kinase inhibitor therapy. Nevertheless, in cases of cryptic translocations and presentations at advanced stages, diagnosing individuals with CML might be difficult. A bone marrow aspirate and coordination with pathology are required in suspected instances to guarantee enough sampling to identify the BCR-ABL1 translocation, preventing misdiagnosis and delaying therapy.

Interprofessional teamwork and decision-making with the patient are crucial, and side effects that can make it difficult for the patient to comply with their treatment plan should be discussed with them directly. Tyrosine kinase inhibitors work in the majority of instances, however patient non-compliance is a major factor in failure.

The pharmacist must confirm the compatibility and dose of all chemotherapeutic agents, look for medication interactions, and inform the team of any side effects. Early side effect detection, prioritizing patient concerns, and swift problem-solving are essential requirements for the healthcare team. The best treatment for patients with CML will come from an organized interprofessional team approach combining nurses, primary care physicians, pharmacists, and specialists.

Dr. Durgesh Kumar Sinha
Dr. Durgesh Kumar Sinha

MBBS MS [ OPHTHALMOLOGY ]

Updated on: 30-Mar-2023

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