Leukemia: Causes, Symptoms, Risk factors, Diagnosis, and Treatments
Leukemia is a cancer of blood cells (white blood cells) or bone marrow. Leukemia usually affects the people over the age of 55 years and is also the common type of cancer in people below the age of 15 years.
Leukemia usually occurs when the white blood cells (leukocytes) begin to grow rapidly and abnormally. White blood cells are the immune cells that fight against the infection causing organisms. The abnormal white blood cells accumulate and losses the ability to fight against the infection.
- What is Leukemia?
- Types of Leukemia:
- What Causes Leukemia?
- Symptoms of Leukemia:
- Risk Factors for Leukemia:
- Diagnosis of Leukemia:
- Treatment for Leukemia:
What is Leukemia?
Leukemia is the cancer of white blood cells (blood cells). In normal cell-cycle, the cells grow, divide and die, but in leukemia, this pattern is lost. The cells tend to grow abnormally without dying. Leukemia occurs when there is a dysfunction in the cell-cycle regulation.
Types of Leukemia:
Based on the growth rate and origin of cancer, leukemia is divided into four types, they are:
Acute myeloid leukemia (AML):
Acute myeloid leukemia usually affects the myeloid lining of the blood cells. AML begins in the bone marrow (spongy and gelatinous tissue present in the bone) and rapidly moves in the bloodstream that may spread to other parts of the body.
Chronic myeloid leukemia (CML):
Chronic myeloid leukemia is a rare type of slowly-progressing leukemia that originates due to genetic changes in the myeloid cells (the cells that produce blood cells except lymphocytes). It usually occurs due to the accumulation of cancerous cells from a long duration.
Acute lymphocytic leukemia (ALL):
ALL usually develops due to abnormalities in the DNA of bone marrow. In acute lymphocytic leukemia, a large number of lymphoblasts (immature and abnormal blood cells) are produced that affects white blood cells. ALL is the common type of leukemia in children.
Chronic lymphocytic leukemia (CLL):
CLL is a type of leukemia that begins in lymphoid blood cells and affects a type of white blood cells. The person may not experience any symptoms as CLL progresses slowly over months and years.
What Causes Leukemia?
The exact cause of leukemia remains unknown. But the researchers believe that leukemia usually occurs when there is damage in the DNA of immature white blood cells. The damaged blood cells grow and divide rapidly, thereby replacing the healthy blood cells.
The abnormal blood cells accumulates in the body and do not die and prevent the proper growth and functioning of healthy white blood cells and cause leukemia.
Symptoms of Leukemia:
The person may not experience any symptom immediately. It takes some months to years for an individual to develop symptoms of leukemia. The symptoms change depending on the type of leukemia. The most common symptoms of leukemia include:
- Unintentional weight loss
- Inflamed lymph nodes
- Inability to clot blood quickly
- Severe and frequent infections
- Excessive sweating during nights
- Bone pain
Risk Factors for Leukemia:
Factors that increase the risk of leukemia include:
Previous History of Cancer Therapy:
Individuals who have undergone chemotherapy and radiation therapy for treating other types of cancers are at increased risk of developing leukemia.
A Family History of Leukemia:
Individuals having a family history of leukemia are at increased risk of developing leukemia.
Genetic disorders are due to genetic abnormalities, and the person with any genetic conditions, such as Down syndrome is at increased risk of leukemia.
Exposure to Certain Chemicals:
Long-term exposure to certain chemicals, such as gasoline, benzene, and car exhaust causes certain changes in the chromosomes present in the bone marrow cells and increases the risk of leukemia.
The smoke released from the cigarette contains certain chemicals, such as benzene, which increases the risk of leukemia.
Diagnosis of Leukemia:
The doctor will initiate the diagnosis by reviewing the family history, medical history and signs and symptoms of the individual. A physical test is carried out to assess the general health, and to evaluate the physical signs of leukemia, such as pale skin due to anemia, inflamed lymph nodes, and an enlarged spleen or the liver.
A physical test is not enough to confirm the diagnosis, so the doctor recommends certain tests, such as:
Complete Blood Test:
A complete blood test is performed to assess the overall health of the person. In this procedure, a sample of blood is collected and is examined to determine the levels of red blood cells (RBCs), white blood cells (WBCs), blood platelets. Any abnormal levels in the blood components suggest leukemia.
A biopsy is done by taking a small sample of tissue from the bone marrow or the lymph nodes, by using a sterilized needle and is examined under a microscope. The biopsy is done under the influence of a local anesthetic, a sedative or a general anesthetic. A biopsy is used to evaluate the type and growth rate of leukemia.
Bone Marrow Aspiration:
Bone marrow aspiration is a diagnostic procedure used to evaluate the fluid and tissue present in the bone marrow. This procedure is done under the influence of local anesthetic. In this procedure, a sample of soft tissues is collected from the bones and is examined to detect chromosomal changes. Any abnormalities in the chromosomes reveal leukemia.
Other tests, such as chest X-rays, lumbar puncture, CT (computerized tomography) scan, and MRI (magnetic resonance imaging) are also performed to evaluate the extent of the disease.
Treatment for Leukemia:
The treatment is done based on the patient’s age, type, and stage of leukemia. The main target of the treatment is to destroy the cancer cells and bring the disease to remission. The common treatment options for leukemia include:
Chemotherapy is the common treatment that uses drugs for treating leukemia. The drug therapy is prescribed based on the type of leukemia.
Radiation therapy uses high-energy radiation to inhibit the growth of leukemia. Radiation therapy acts by damaging the DNA (genetic material present in the cell), thereby killing and preventing the growth of cancerous cells. Radiation therapy can also be used in combination with chemotherapy.
Biological therapy can be used with other anti-cancer therapies for treating leukemia. This therapy slows the growth and prevents the spread of cancer to other parts of the body.
Targeted therapy involves the use of drugs that identifies and attacks specific cancerous cells without causing much harm to the normal cells.
Stem-cell transplantation is performed to replace the diseased bone marrow with new bone marrow. The stem cell transplantation may involve the use of patient’s own bone marrow or bone marrow from another person (donor).
The patients are advised to undergo chemotherapy or radiation therapy for destroying the damaged bone marrow before undergoing stem-cell transplantation.