Leukemia is a cancer of the tissues that make up the blood, bone marrow, and lymphatic system. It prevents the body from producing healthy red blood cells, platelets, and mature white blood cells (leukocytes) There are many types of leukemia. Some are more common in children, and others in adults.

Leukemia involves the white blood cells, which are responsible for defending the body from infection and eliminating residue and waste from tissues. These cells grow and divide in an ordered fashion as the body needs them, but in people who have leukemia, the bone marrow produces abnormal white blood cells that don’t work properly.

Although signs can vary depending on the type of leukemia, the most typical ones are weakness and persistent fatigue, involuntary weight loss, frequent or serious infections, fever, chills, reddish blotches on the skin, bone pain or sensitivity, excessive night sweats, bleeding or bruising easily, and enlarged liver or spleen.

Causes of leukemia

Leukemia is thought to start when the DNA of certain blood cells mutates, but there may be other changes that cause it that are not yet understood. Some anomalies cause the cell to grow, divide rapidly, and stay alive longer than usual. Over time, these abnormal cells can displace the healthy blood cells of the bone marrow, causing signs of leukemia.

Some of the risk factors for leukemia include previous cancer treatments (chemotherapy and radiation therapy), genetic disorders (Down syndrome), exposure to chemical substances (benzene), smoking, and family history of leukemia. However, most people who have risk factors do not have leukemia, and many patients who have leukemia did not have any risk factors.

Types

Leukemia can be classified into two main groups. The first group is determined by how quickly it grows: acute leukemia, where cells multiply rapidly, or chronic leukemia, where cells replicate and accumulate slowly. The other type of classification is by the type of white blood cell affected: lymphocytic leukemia (lymphoid cells or lymphocytes) or myelogenous leukemia (myeloid cells)

Acute myelogenous leukemia (AML)

AML is the most common type of leukemia. It affects the cells in the bone marrow that usually grow into white blood cells, causing them to accumulate and not leave room for the formation of healthy red and white blood cells and platelets. Since there are not enough healthy cells, this increases the risk of anemia, bleeding, and infection.

Chronic myelogenous leukemia (CML)

This type of leukemia primarily affects adults. CML causes uncontrolled growth of immature and mature cells that make white blood cells, called myeloid cells. The diseased cells accumulate in the bone marrow and blood. People who have CML have few or no symptoms for months or years before entering a phase where cells grow more rapidly.

Acute lymphocytic leukemia (ALL)

This is the most common type of leukemia in young children. ALL occurs when the bone marrow produces a large number of immature lymphoblasts, which grow rapidly and replace normal cells in the bone marrow, preventing blood cells from being produced. Life-threatening symptoms may develop as normal blood counts lower.

Chronic lymphocytic leukemia (CLL)

This type is most common in adults. You might even feel fine for years without needing treatment. CLL causes an increase in a certain type of white blood cell, B cells, which affects the lymph nodes and other organs, such as the liver and spleen. Eventually, it can cause the bone marrow to lose its function.

Other types

There are other, less common types of leukemia, such as myelodysplastic syndromes, myeloproliferative disorders, and hairy cell leukemia. This last type is caused by the abnormal proliferation of B cells. Under a microscope, these cells look “hairy,” as they have thin projections that extend out from their surface.

Treatments

Health professionals will make a diagnosis in order to determine the best treatment. This may include medications and chemotherapy that are given intravenously or intrathecally (through the spinal canal), radiation therapy, biological therapy (which seeks to stimulate or boost the immune system), or bone marrow transplant.

Doctors often also recommend other activities or lifestyle changes to relieve the symptoms of leukemia and prevent it from getting worse. For example, doing aerobic exercise and maintaining a balanced diet have been shown to help alleviate depression and bone and muscle weakness caused by this disease.

Sources:

National Library of Medicine; Cleveland Clinic; Mayo Clinic; National Cancer Institute; American Cancer Society.