Leukemia is cancer that starts in blood-forming tissue, such as the bone marrow, and causes large numbers of blood cells to be produced and enter the bloodstream. Each year, it is diagnosed in about 29,000 adults and 2,000 children in the United States.
Understanding Normal Blood Cells
Blood cells form in the bone marrow.
Bone marrow is the soft material in the center of most bones. Immature blood cells are called stem cells and blasts. Most blood cells mature in the bone marrow and then move into the blood vessels. Blood that flows through the blood vessels and the heart is called peripheral blood.
Understanding Leukemia Cells
In people with leukemia, the bone marrow produces abnormal white blood cells, which are
leukemia cells. At first, these cells function almost normally. In time, they may crowd out normal white blood cells, red blood cells, and platelets, which makes it hard for blood to do its work.
The different types of leukemia are grouped by how quickly the disease develops and gets worse (chronic versus acute). The types are also categorized by which blood cells are affected (lymphoid versus myeloid).
There are four common types of this disease:
No one knows the exact cause of this disease, and doctors can seldom explain why one person will get it and another person will not. However, research has shown that people with certain risk factors are more likely than others to develop the disease (a risk factor is anything that increases a person's chances of developing a disease).
Risk factors include:
- Exposure to very high levels of radiation
- Working with certain chemicals
- Receiving chemotherapy
- Having Down syndrome or other genetic conditions
- Having human T-cell leukemia virus-1 (HTLV-1)
- Having myelodysplastic syndrome.
Like all blood cells,
leukemia cells travel through the body. Depending on the number of abnormal cells and where these cells collect, patients may have a number of symptoms.
Common symptoms may include:
- Fevers or night sweats
- Frequent infections
- Feeling weak or tired
- Headache
- Pain in the bones or joints
- Swelling or discomfort in the abdomen (from an enlarged spleen)
- Swollen lymph nodes, especially in the neck or armpit
- Weight loss
- Bleeding and bruising easily (e.g., bleeding gums, purplish patches in the skin, or tiny red spots under the skin).
It is important to note that these symptoms are not sure signs of this illness. An infection or another problem could also cause these symptoms. People who have symptoms should see a doctor as soon as possible -- only a doctor can make a diagnosis and treat the problem.
If a person has possible
leukemia symptoms, the doctor will need to perform a physical exam, ask about the patient's personal and family medical history, and order laboratory tests (especially blood tests).
Exams and tests that are used to make a diagnosis may include:
- Physical exam
- Blood tests
- Biopsy.
After leukemia has been diagnosed, tests are done to determine how far the cancer has spread in the blood and bone marrow. Normally, this process is called staging; however, unlike most other forms of cancer, most types of this disease are not classified using a standard staging system. The progression of different types of leukemia is classified in different ways, and it's important to determine this classification before planning treatment.
(Click Stages of Leukemia for more information about how the different types are classified.)
Treatment options vary based on the type of leukemia that a person has. Some factors that may influence the treatment include:
- The type of leukemia (see Types of Leukemia)
- The patient's age
- Whether leukemia cells are present in the cerebrospinal fluid
- Whether the leukemia has been treated before
- Certain features of the leukemia cells
- The patient's symptoms and general health.
In general, treatment can include:
Choosing the most appropriate cancer treatment is a decision that ideally involves the patient, the family, and the healthcare team.
