Leukemia

Posted by Kingsway Hospitals-The Best Multispecialty hospital on December 16th, 2020

All about Leukemia!!

Leukemia is a cancer of the blood or bone marrow. Bone marrow produces blood cells and a problem with blood cell production may lead to leukaemia which usually affects the leukocytes or white blood cells. There is a rise in the number of abnormal white blood cells in the body.

Unlike other cancers, leukemia generally doesn’t form into a mass or tumor which can be identified in imaging tests, such as X-rays.

There are many types of leukaemia. Some are more common in children; others are more common in adults. 

CAUSES OF LEUKEMIA:

The exact cause of leukemia is not known. It is believed to result from a combination of genetic and environmental factors.

Leukaemia develops when the DNA of developing blood cells in the bone marrow, mainly white blood cells, changes or mutates. Due to this, the blood cells can’t develop or grow properly and divide uncontrollably.

RISK FACTORS OF LEUKEMIA:

There are various factors which may increase the risk for leukemia: 

i) Artificial ionizing radiation: Previous history of radiation therapy for cancer treatment. 

ii) Certain viruses: Such as human T-lymphotropic virus (HTLV-1) may be linked to leukemia.

iii) Chemotherapy: Person who has received chemotherapy treatment for a previous cancer is more prone to develop leukemia later in life.

iv) Exposure to certain chemicals: Such as benzene which is found in gasoline and is used by the chemical industry. It is linked to an increased risk of some types of leukemia. Other chemicals may include diesel, and pesticides, hair dyes, etc.

v) Genetic conditions: Such as Down syndrome (trisomy with chromosome 21) which has increased risk of acute myeloid or acute lymphocytic leukemia (AML/ALL) in children compared to the children without Down syndrome. Another example of a genetic condition which links to leukemia is Li-Fraumeni syndrome (change in TP53 gene).

vi) Family history of leukaemia: If a close family member has been diagnosed with leukemia, your risk for the disease may be increased.

vii) Problems with the immune system: Certain inherited immune conditions increase the risk of leukemia which include:

· Ataxia-telangiectasia

· Bloom syndrome

· Schwachman-Diamond syndrome

· Wiskott-Aldrich syndrome

Deliberate suppression of the immune system may lead to childhood leukemia. This suppression might occur after an organ transplant as a child may take medications to prevent the body from rejecting the organ.

viii) Smoking: Smoking increases the risk of developing acute myeloid leukaemia (AML)

ix) Blood disorders: Such as myelodysplastic syndrome, which is sometimes called "preleukemia".

TYPES OF LEUKEMIA:

Leukaemia can be classified based on its speed of progression and the type of cells involved.

1) First classification is based on the progression:

·       Acute leukemia: In acute leukemia, the abnormal blood cells multiply rapidly, so the disease worsens quickly. Aggressive and timely treatment is required for acute leukemia.

·       Chronic leukemia: The disease involves more mature blood cells which replicate or accumulate more slowly and can function normally for a while. Early symptoms may be very mild which can go unnoticed or undiagnosed for years.

2)Second classification is based on the type of cell involved: 

·       Lymphocytic/ lymphoblastic leukemia: This type of leukemia affects the lymphoid cells (lymphocytes).

·       Myelogenous leukemia: This type of leukemia affects the myeloid cells. Myeloid cells are immature blood cells which give rise to red blood cells, white blood cells and platelets.

The major 4 types of leukemia are:

·       Acute lymphocytic leukemia (ALL): This is the most common type of leukemia in young children, those children under 5 years of age being at the highest risk. ALL can also occur in adults, usually over the age of 50 years. It may spread to lymph nodes and central nervous system.

·       Acute myelogenous leukemia (AML): AML is a common type of leukemia. It occurs in children and adults (more common in adults). It is the most common type of acute leukemia in adults and develops more often in men than in women. Triggers may include environmental factors.

·       Chronic lymphocytic leukemia (CLL): It is the most common chronic adult leukemia which is most common over 55 years of age, but younger adults can also develop it. It is more common in men than in women and rarely affects children. A person may feel well for years without needing treatment.

·       Chronic myelogenous leukemia (CML): A person with CML may have few or no symptoms for months or years and might not be diagnosed with it until he has a routine blood test. People at the age of 65 and above have a higher risk of this type.

Other types: Rarer types include hairy cell leukemia (a very rare subtype of CLL), large granular lymphocytic (LGL) leukemia, B-cell prolymphocytic leukemia (B-PLL), T-cell prolymphocytic leukemia (T-PLL), myelodysplastic syndromes and myeloproliferative disorders such as chronic myelomonocytic leukemia (CMML), juvenile myelomonocytic leukemia (JMML), etc. 

SYMPTOMS OF LEUKEMIA:

Different types of leukemia can cause different problems. Sometimes, there might be no signs in the early stages of some forms. Symptoms of leukemia may include the following:

· excessive sweating, especially at night (called “night sweats”)

· persistent fatigue and weakness/ tiredness

· unintentional weight loss (If the liver or spleen becomes swollen, a person may feel full and eat less, resulting in weight loss. Weight loss may also occur even without an enlarged liver or spleen.)

· bone pain and tenderness

· painless, swollen lymph nodes (especially in the neck and armpits)

· enlargement of the liver or spleen

· red and purple spots on the skin called petechiae (due to poor blood clotting)

· bleeding and bruising easily but slow healing (due to poor blood clotting)

· recurrent nosebleeds

· fever or chills

· frequent and severe infections (due to the abnormal working of white blood cells)

· flu-like symptoms

· anaemia: shortness of breath and pale skin

Leukemia symptoms can also be seen in organs affected by the cancer cells. For example, the spread of cancer to the central nervous system can cause headaches, nausea and vomiting, confusion, loss of muscle control, and seizures. Leukemia can also spread to other parts of your body, such as lungs, gastrointestinal tract, heart, kidneys, testes, etc.

Proper and timely consultation and testing are necessary to confirm a diagnosis of leukemia.

DIAGNOSIS OF LEUKEMIA:

If a person has signs or symptoms that suggest leukemia, they may consult the doctor and undergo the following diagnostic exams:

i) Physical exam: 

The doctor will examine for physical signs of leukemia, such as pale skin from anemia, swollen lymph nodes, and enlargement of liver and spleen. He will also take detailed family and medical history.

ii) Blood tests:

A complete blood count (CBC) shows the number and maturity of different types of blood cells such as red or white blood cells or platelets and abnormal levels in them may suggest leukemia. A blood smear shows any unusual or immature cells.

iii) Bone marrow test:

The doctor may recommend a procedure to remove a sample of bone marrow from the hipbone. The surgeon removes the bone marrow sample using a long, thin needle. The sample is sent to a laboratory to examine for leukemia cells. Specialized tests of leukemia cells may reveal certain characteristics which can help in deciding the treatment plan.

iv) Spinal tap:

It involves fluid from the spinal cord which can tell about the spread of leukemia.

v) Imaging tests:

Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and Positron Emission Tomography (PET) scans can help spot signs of leukemia.

vi) Other tests:

Flow cytometry: DNA of the cancer cells is examined to determine their growth rate.

Liver function tests: To examine whether cancer has spread to the liver.

TREATMENT OF LEUKEMIA:

Hematologist and oncologist are usually involved in treating leukemia. These are doctors who specialize in blood disorders and cancer respectively. The treatment plan for a patient depends on the type of leukemia, their age and the overall state of health and spread to other parts of the body. Common treatments include:

i) Chemotherapy: 

Chemotherapy is the major form of treatment for leukemia. This treatment uses drugs to kill leukemic cells. Depending on the type of leukemia, a single drug or a combination of drugs is given to the patient. These drugs may be given in a pill form or may be injected directly into a vein using either a drip or a needle. Noncancerous cells can also be damaged by the treatment and can cause severe side effects, including hair loss, weight loss, and nausea.

Chemotherapy is the primary treatment for AML.

ii) Biological therapy/ Immunotherapy: 

Biological therapy uses treatments that help the patient's immune system recognize and attack leukemic cells. Drugs like interleukins and interferon can help to boost the body's natural defences against leukemia.

iii) Targeted therapy: 

Targeted therapy uses drugs to block specific genes or proteins that cancer cells need to grow. Tyrosine kinase inhibitors are used in this treatment. Examples include imatinib, dasatinib, and nilotinib. Imatinib (Gleevec) is a targeted drug that’s commonly used against CML.

iv) Radiation therapy: 

Radiation therapy uses X-rays or other high-energy beams to damage leukemic cells and stop their growth. Radiation can be applied to a specific area or to your entire body. Radiation therapy may also be used as a preparative for a stem cell transplant.

v) Stem cell transplant: 

A stem cell transplant involves the replacement of diseased bone marrow with healthy bone marrow. Before a stem cell transplant, high doses of chemotherapy or radiation therapy are given to destroy the diseased bone marrow. Then an infusion of blood-forming stem cells is infused that helps to rebuild the bone marrow.

The patient may receive stem cells from a donor (called allologous transplantation), or in some cases, one may be able to use their own stem cells (called autologous transplantation). 

Stem cell transplant can be effective in treating CML. Younger people with leukemia are more likely to undergo a successful transplant than older adults.

vi) Surgery: 

Surgery often involves removing the spleen, if it is filled with cancerous cells and is pressing nearby organs. It is called as splenectomy.

Various medical specialists need to collaborate to collectively plan the treatment of leukemia. Haematologists are the doctors who specialize in blood, bone marrow, and immune cell disorders. Oncologists are the ones who treat cancerous tumors. Pathologists work with these doctors to assist in treatment planning and identify if a particular treatment is working or not. 

An excellent team of specialists like that of hematologists, oncologists, pathologists and surgeons can be found at the one-stop destination "Kingsway Hospitals, Nagpur".