Chronic Myeloid Leukemia is classified as a myeloproliferative neoplasm (MPN). It is therefore a malignant disease of the bone marrow’s blood-forming cells that causes an uncontrolled expansion of leukocytes (white blood cells) in the blood, particularly mature and maturing granulocytes (progenitor cells). The quantity of blood platelets is frequently raised at the start of the disease (thrombocytosis).
Learn more about CML : It is a cancer that affects the bone marrow and blood cells
Which factors lead to CML?
Chemical compounds such as benzene and radioactive radiation from Hiroshima and Nagasaki are risk factors. Both of these variables can cause bone marrow blood stem cells to deteriorate. The leukemia cells in approximately 90% of people with chronic myeloid leukemia contain a unique genetic abnormality known as the Philadelphia chromosome. It is the outcome of a genetic material exchange between chromosomes 9 and 22. (a so-called bcr-abl1 fusion gene). According to current research, heredity does not play a role.
What are the symptoms of CML?
Chronic myeloid leukemia (CML) usually begins insidiously and can last for several years. It is often detected by a routine blood test as part of a preventive medical check-up, and can cause an enlargement of the spleen and pain in the upper left abdomen. In advanced stages, leukemia causes the number of healthy, functioning blood cells to decrease, leading to a disruption of all three cell rows.
- Lack of erythrocytes ( anemia ): weakness, paleness, reduced performance, shortness of breath
- Lack of platelets (thrombocytopenia): Increased tendency to bleed, which can show up as nosebleeds or bruising (hematomas).
- Lack of functional white blood cells: Increased susceptibility to infections
The sometimes overwhelming rise in white blood cells can also contribute to the formation of clots and vascular occlusions, but this is uncommon due to the mature cells’ good deformability. In this scenario, we’re talking about leukemic thrombi.
How is CML diagnosed?
History and physical examination
The doctor begins with a thorough discussion of present symptoms and potential risk factors ( anamnesis ). He next checks the spleen and liver, among other organs, which can swell with CML. An ultrasound examination of the abdomen can also be used to measure the size of the organs.
The blood shows characteristic alterations. The number of white blood cells (leukocytes) is dramatically raised in the complete blood count, owing to a rise in the number of mature and immature granulocytes. Platelets in the blood may be raised as well. When CML has progressed, there is a paucity of red blood cells (anemia) and blood platelets.
Bone marrow examination
Following the blood test, a bone marrow examination is required to confirm the diagnosis. Under local anesthetic, bone marrow is extracted from the iliac crest (punch biopsy). This test is often performed as an outpatient procedure, requiring no hospitalization.
Evidence of genetic modification: The Philadelpia chromosome
Cytogenetic examinations can detect the Philadelphia chromosome, which is a translocation of genes 9 and 22 in the blood and bone marrow. Rarely, this gene change can be found in acute leukemia, but the course of the disease and treatment differ from normal CML.
How is CML treated?
Hematological response to therapy
Under therapy, the blood count returns to normal, which is referred to as the haematological response. The spleen has recovered to normal size as well. This stage is usually reached a few weeks after starting therapy.
Cytogenetic response to therapy
In the case of a cytogenetic response, bone marrow cells in the division phase are inspected microscopically. The cytogenetic reaction is reflected in fewer cells carrying the Philadelphia chromosome. When the Philadelphia chromosome is no longer detectable, it is said to be in complete cytogenetic remission. This milestone is usually reached after roughly six months.
molecular response to therapy
The polymerase chain reaction can be used to detect the bcr-abl transfusion gene (PCR). A good molecular remission is defined as the bcr-abl value falling below 0.1 percent of the original value. This goal should have been met 12 months after starting therapy.
Cancer specialists use tyrosine kinase inhibitors, especially imatinib, as standard therapy for chronic myeloid leukemia (CML). Newer tyrosine kinase inhibitors, such as nilotinib and dasatinib, are now also approved for the initial treatment of CML. At the beginning of treatment with imatinib, the drug can cause changes in the blood count, nausea, diarrhea, water retention in the tissue (edema), skin rashes, and muscle cramps. However, the side effects decrease with increasing duration of therapy. It is important to use the prescribed medication regularly, and therapy is often lifelong. If there is an optimal response, stopping or pausing the tyrosine kinase inhibitor can be attempted, preferably as part of a study. If there is a lack of response, a change in tyrosine kinase inhibitors is also an option.
Other drug therapy options
Since tyrosine kinase inhibitors were approved for the treatment of CML in 2002, other therapies have taken a back seat. They are still employed, however, when the response to tyrosine kinase inhibitors is insufficient. Interferon-alpha, hydroxyurea, and chemotherapeutic medicines are among the medications utilized here.