Leukemia is a cancer of the blood cells.
Leukemias are grouped by how quickly the disease develops (acute or chronic) as well as by the type of blood cell that is affected (lymphocytes or myelocytes). The four main types of leukemia include acute lymphocytic leukemia (ALL), chronic lymphocytic leukemia (CLL), acute myelocytic leukemia (AML), and chronic myelocytic leukemia (CML).
People with leukemia are at significantly increased risk for developing infections, anemia, and bleeding. Other symptoms and signs include easy bruising, weight loss, night sweats, and unexplained fevers.
The diagnosis of leukemia is supported by findings of the medical history and examination, and examining blood and bone marrow samples under a microscope.
Treatment of leukemia depends on the type of leukemia, certain features of the leukemia cells, the extent of the disease, and prior history of treatment, as well as the age and health of the patient.
Most patients with leukemia are treated with chemotherapy. Some patients also may have radiation therapy and/or bone marrow transplantation.
The prognosis of leukemia depends upon several factors, including the patient's age, the type of leukemia, and the extent to which the cancer has spread.
In summary, the four main types of leukemia are as follows:
• Acute lymphocytic leukemia
• Chronic lymphocytic leukemia
• Acute myelocytic leukemia
• Chronic myelocytic leukemia
Less common types include hairy cell leukemia and human T-cell leukemia.
Leukemia affects people of all ages. Approximately 85% of leukemias in children are of the acute type.
• Acute lymphocytic leukemia (ALL) affects both children and adults but is more common in children. It accounts for 65% of the acute leukemias in children.
• Chronic lymphocytic leukemia (CLL) is essentially an adult disorder and is almost twice as common as chronic myelocytic leukemia.
• Acute myelocytic leukemia (AML) is the most common acute leukemia in adults.
• Chronic myelocytic leukemia (CML) is far more common in adults than in children.
Leukemia CausesWhile the exact cause(s) of leukemia is not known, risk factors have been identified.
As with other cancers, smoking is considered a risk factor for leukemia, but many people who develop leukemia have never smoked, and many people who smoke never develop leukemia.
Long-term exposure to chemicals such as benzene or formaldehyde, typically in the workplace, is considered a risk factor for leukemia, but this accounts for relatively few cases of the disease.
Prolonged exposure to radiation is a risk factor, although this accounts for relatively few cases of leukemia. Doses of radiation used for diagnostic imaging such as X-rays and CT scans are nowhere near as prolonged or high as the doses needed to cause leukemia.
Other risk factors for leukemia include the following:Previous chemotherapy: Chemotherapy, particularly certain of the alkylating agents and topoisomerase inhibitors, used to treat certain types of cancers, are linked to development of leukemia later. It is likely that radiation treatment adds to the risk of leukemia associated with certain chemotherapy drugs.
Human T-cell leukemia virus 1 (HTLV-1): Infection with this virus is linked to human T-cell leukemia.
Myelodysplastic syndromes:This unusual group of blood disorders (formerly referred to as "preleukemia") is characterized by abnormal blood cell development and a highly increased risk of leukemia.
Down syndrome and other genetic diseases:Some diseases caused by abnormal chromosomes may increase risk for leukemia.
Family history:Having a first-degree relative (parent, brother, sister, or child) who has chronic lymphocytic leukemia increases one’s risk of having the disease by as much as four times that of someone who does not have an affected relative. About 20% of people with chronic leukemia do not have symptoms at the time their disease is diagnosed.
Leukemia SymptomsSome symptoms of leukemia are due to deficiencies of normal blood cells. Others are due to collections of leukemia cells in tissues and organs. Leukemia cells can collect in many different parts of the body, such as the testicles, brain, lymph nodes, liver, spleen, digestive tract, kidneys, lungs, eyes, and skin -- in effect, virtually every tissue site.
The following symptoms of leukemia are common to all types:
• Unexplained fevers
• Frequent infections
• Night sweats
• Fatigue (feeling tired or washed out)
• Weight loss
• Easy bleeding or bruising
Collection of leukemia cells in certain parts of the body may cause the following symptoms:
• Balance problems
• Blurred vision
• Painful swellings in the neck, under the arms, or in the groin
• Shortness of breath
• Nausea or vomiting
• Abdominal pain and/or swelling
• Testicular pain and/or swelling
• Pain in the bones or joints
• Weakness or loss of muscle control
SeizuresIt is important to emphasize that the symptoms of leukemia are nonspecific. This means that they are not unique to leukemia but are common to a number of diseases and conditions. Only a medical professional is able to distinguish leukemia from the other conditions that cause similar symptoms. back to the top
Document by ACS