Leukemia is a cancer that affects the blood and bone marrow, it starts in a cell in the bone marrow. White blood cells help the body fight infections, blood cells form in bone marrow.
In leukemia, the bone marrow makes abnormal white blood cells, which overwhelm healthy blood cells, making it difficult for the blood to do its job.
What is leukemia ?
Leukemia is cancer of the body’s hematopoietic tissues including: bone marrow and lymphatic system.
Leukemia begins in immature or growing cells of the bone marrow, the soft, porous tissue found in the central compartments of the bone. Bone marrow produces all types of blood cells:
- Red blood cells carry oxygen and other materials to body tissues
- Anti-infectious white blood cells (WBC)
- Platelets help blood to clot
Hundreds of billions of new blood cells are produced in the bone marrow each day providing the body with a constant supply of fresh, healthy cells.
In patients with leukemia, there are many white blood cells produced in the bone marrow that do not mature normally. These abnormal cells called white blood cells cannot fight infection in the way healthy white cells can. As they grow in large numbers, white blood cells also interfere with the production of other blood cells.
Many types of leukemia exist. Some forms of leukemia are more common in children, other types of leukemia occur primarily in adults.
Types of leukemia
There are several different types of leukemia, different types are classified based on the type of leukemia cells associated with lymphocytes or medullary cells and whether the disease develops very rapidly (acute disease) or slowly. time (chronic disease).
- Lymphocytic leukemia: develops from cells that produce T lymphocytes (T cells), B lymphocytes (B cells) or natural killer (NK) cells. Each type of cell has a specific role in the immune system, some produce antibodies, while others directly fight or control other immune cells against infection.
- Leukemia: develops from cells that produce white blood cells called granulocytes and mononuclear leukocytes. They release enzymes called Granulocytes when bacteria or fungi invade. Mononuclear cells eventually become macrophages, submerging and destroying bacteria and fungi.
The most common types of leukemia are:
- Acute lymphocytic leukemia (ALL): ALL is the most common type of leukemia in children, it also affects adults, especially those 65 years and older. ALL affects the type of lymphocytes.
- Acute myeloid leukemia (AML): AML occurs in both adults and children and is sometimes called non-lymphocytic acute leukemia. AML affects the type of white blood cells, red blood cells and cells that make platelets.
- Chronic lymphocytic leukemia (CLL): CLL most often affects adults over 55 and rarely occurs in children. CLL affects the type of lymphocytes.
- Chronic myeloid leukemia (CML): CML occurs primarily in adults, but a small number of children also have this type of leukemia. CML affects the type of white blood cells, red blood cells and cells that make platelets.
What is the cause of leukemia?
Leukemia results when the DNA of a cell in the bone marrow is damaged. This is called mutation and changes the cell’s ability to grow and function normally. Moreover, all cells derived from that original cell also have mutated DNA.
What causes DNA damage in the first place, however, is unknown. Scientists have been able to identify changes in several chromosomes of patients diagnosed with different types of leukemia.
Although the exact cause of the DNA mutation leading to leukemia is unknown, scientists have uncovered a number of factors that can put a person at high risk for a form of the disease.
Factors that increase the risk of developing leukemia
- Genetics: People with Down syndrome and some other genetic conditions get leukemia more often.
- Ionizing radiation: Exposure to high-dose ionizing radiation such as radiation treatment for other cancers is associated with the development of all types of leukemia except CLL.
- Medications: People who are treated with certain anti-cancer drugs (such as alkalizing agents) have a higher risk of leukemia.
- Workplace chemical exposure: Long-term exposure to chemicals such as benzene and ethylene oxide have been shown to increase the risk of leukemia.
- Smoking: Researchers believe that up to 20% of acute myeloid leukemia (AML) can be caused by smoking.
- Blood disorders: People with blood cell formation disorders including polycythemia, essential thrombocytopenia and chronic myeloid leukemia (CML) are at high risk for acute myeloid leukemia ( AML).
- Virus: Certain forms of leukemia are caused by a rare virus.
The symptoms of leukemia
In both acute and chronic leukemia, as the number of white blood cells increases, normal cells are expelled from the bone marrow and symptoms may begin to develop.
The symptoms of acute leukemia usually appear suddenly and may be similar to those of a virus or flu. The symptoms may be severe enough that they prompt the patient to see a doctor immediately after onset.
When chronic leukemia first develops symptoms may not arise for several years. CLL and CML are often detected as a random finding of elevated white blood cell counts during routine blood tests as part of regular testing. However, with the passage of time as the number of diseased cells increases they can enter the bone marrow or other organs to the point that they cause serious problems.
The most common signs and symptoms that may develop from acute or chronic leukemia include:
- Bruising and bleeding: due to low platelet count blood components are important for blood clotting and wound healing
- Infection due to low levels of white blood cells against disease
- fever, night sweats, unintentional weight loss and fatigue
White blood cells can also invade the liver, spleen, lymph nodes and other organs, especially in CLL and ALL, causing discomfort or damage to normal organ function.
These symptoms may also be caused by other conditions and do not necessarily mean you have leukemia. Talk to your doctor if you have any of these symptoms to ensure proper diagnosis and treatment.
Because chronic leukemia shows no obvious symptoms in its early stages, it can be diagnosed during regular physical examination or as a result of regular blood tests.
To diagnose leukemia the doctor must check the cells from the blood and in most cases bone marrow.
- Blood test: By examining a sample of your blood, your doctor can determine if you have abnormal levels of red blood cells or white blood cells or platelets to be able to identify leukemia.
- Bone marrow test: Your doctor may recommend a procedure to remove a bone marrow sample from your hip bone with a long thin needle. The tissue sample is sent to a lab to look for leukemia cells, and specialized tests of your leukemia cells may reveal certain characteristics used to identify options. Choose your treatment.
Once leukemia is diagnosed, it will be staged to help the doctor determine the patient’s prospects:
- AML and ALL are staged based on how cancer cells look under a microscope and related cell types.
- ALL and CLL are staged based on the number of WBCs at the time of diagnosis.
The presence of immature white blood cells or myeloblasts in the blood and bone marrow are also used to diagnose the stage of AML and CML.
How to treat leukemia?
Treatment varies according to the type of leukemia acquired by the patient, the stage of the disease and the patient’s overall health.
Acute lymphocytic leukemia
The standard treatments for acute adult-onset lymphocytic leukemia (ALL) are chemotherapy and stem cell transplantation .
Depending on the features of this disease you may also receive a type of immune therapy in which your immune cells are designed to search and destroy cancer called cell therapy CAR. T .
The standard prepaid treatment for ALL is usually divided into three stages:
- strengthen and consolidate
Acute myeloid leukemia
The standard treatments for acute myeloid leukemia (AML) include chemotherapy and stem cell transplantation also known as bone marrow transplant.
Radiation therapy is also sometimes used, which may also be given to prepare for stem cell transplantation.
AML treatment is usually divided into two stages:
- Relieved touch treatment
- Treatment after treatment.
Elderly people, especially those with other health problems, may receive less intensive treatment than younger people.
Chronic lymphocytic leukemia
- CLL usually affects older adults and progresses slowly. Current conventional treatments do not usually apply, as long as there are no symptoms that require no treatment.
- If swelling appears in the lymph nodes and other organs CLL can usually be controlled for many years by chemotherapy . Many people with CLL basically live normally and die of unrelated causes.
Chronic myeloid leukemia
Treatment with Tyrosine kinase inhibitors (TKI) is the standard treatment for chronic phase CML. TKIs often succeed in managing CML over the long term. The three approved TKIs are the main treatment for chronic CML:
Modern treatment has basically cured CML, but regular medication needs to be used forever.
CML using the drug can be cured even for patients who fail to succeed in bone marrow transplant.
The long-term outlook for people with leukemia depends on the type of cancer they have and the stage of diagnosis.
The earlier the diagnosis of leukemia and the faster the treatment is, the higher the chance of recovery. A number of factors, such as age, a history of blood disorders and chromosome mutations, can negatively affect outlook.
In many cases leukemia can be managed or cured with current treatments:
- Adult patients treated with ALL have an 80 – 90% chance of remission, about 40% of those treated survive at least 5 more years with a chance of complete cure.
- Patients treated with AML have a 60% to 70% chance of remission, about 30% of those who survive for at least 3 years with a complete cure.
- Human CML has a 5-year survival rate of 68%
- CLLs have a five-year survival rate of 86%.
- Source mayoclinic.org article Leukemia : https://www.mayoclinic.org/diseases-conditions/leukemia/symptoms-causes/syc-20374373 , updated 13/3/2018.
- Source en.wikipedia.org Leukemia article : https://en.wikipedia.org/wiki/Leukemia , updated November 8, 2019.
- A reputable source index-china.com sums up the article What is leukemia? : https://index-china.com/leukemia/, updated 14/3/2020.
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