Leukemia

Leukemia is a type of blood cancer in which there is an excessive production in the bone marrow of abnormal white blood cells.

Bone marrow is the soft tissue found inside the bones where blood cells are made. There are three main types of blood cells:

• White blood cells (leukocytes)
• Red blood cells (erythrocytes)
• Platelets

Blood cells come from blasts cells in the bone marrow. Blasts are precursors to blood cells that are in the early stage of development. These blasts must develop to become either white blood cells, red blood cells or platelets.

When a person suffers from leukemia, blasts multiply uncontrollably filling up the bone marrow and prevent the proper production of other blood cells (bone marrow failure).

These blast cells, usually abnormal white blood cells, also spill out into the bloodstream and spread to other organs and tissues, such as the lymph nodes and the spleen.

Leukemia is caused by critical gene mutation of unknown origin in the DNA of blood cells.

Some known risk factors for leukemia are:

• Genetic predisposition
• Exposure to ionizing radiation
• Viral interferences
• Previous therapy with antineoplastic drugs
• Exposure to toxic agents such as benzene

Leukemia is estimated to affect 12 to 14 people per 100,000 inhabitants each year.

Since leukemia is a group of diseases, many disorders can classify as a leukemia, but may differ in their symptoms and treatments. However, leukemia may be classified regarding different perspectives.

Based in terms of how quickly it develops, leukemia can be classified into:

• Acute: They have a short and drastic course in which the proliferation of blast cells in the bone marrow can be very fast if not treated properly.
• Chronic: It is a slow-growing leukemia, where there are immature cells, but the bone marrow can produce also some healthy blood cells.

Based on the type of blasts and blood cells affected can be classified into:

• Lymphocytic (also known as lymphoid or lymphoblastic leukemia): The blasts are similar to lymphocytes.
• Myeloid (also known as myelogenous): The blasts are more similar to polymorphonuclear leukocytes such as neutrophils, eosinophils, and basophils.

Acute leukemia is more common in children, while chronic leukemia is more common in adults.

Similarly, Lymphocytic leukemia is more common in children, whereas myeloid leukemia is more common in adults and the elderly.

In the early stages of the disease, there are no evident symptoms since there are still healthy blood cells.

Afterwards, the low count of red blood cells, white blood cells, and platelets may cause the following symptoms:

• Anemia (lack of red blood cells): Fatigue, pallor, dizziness or headache.
• Leukopenia (lack of white blood cells): More likely to get infections.
• Thrombocytopenia (lack of platelets): Bruise and bleed excessively.

Other common symptoms may be:

• Splenomegaly: Enlarged spleen
• Swollen lymph nodes
• Joint pain
• Abdominal pain

Leukemia can be detected in a blood test when the blast cells invade the blood.

However, the best test to diagnose leukemia is a bone marrow aspiration and biopsy. With this test, a small amount of fluid is removed from the bone marrow and the blood cells are studied under a microscope.

Each type of leukemia may need a specific treatment. Nevertheless, the following measures can be considered appropriate for the most types of leukemia:

• Chemotherapy and radiation therapy: To stop the proliferation of cells in the bone marrow.
• Bone marrow transplant: Allows the affected person to develop healthy blood cells.