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Overview
Leukemia is a type of cancer of the bone marrow and blood. It was first discovered in the 19th century by European physicians, who called it Weisses blut or white blood. Eventually, the disease was called leukemia, derived from the Greek words leukos meaning white and haima meaning blood.
Chronic lymphocytic leukemia is one of several different types of leukemia. It's also referred to as chronic lymphoid leukemia, or CLL. It is characterized by a gradual increase in the number of white blood cells, or lymphocytes, in the blood and the bone marrow. White blood cells are important because they fight bacteria and protect the body from possible infections.
In chronic lymphocytic leukemia, cancerous lymphocytes build up in the lymph nodes, liver and spleen, causing these areas to get larger. There are a number of kinds of chronic lymphocytic leukemia, and they are classified by the type of lymphocyte involved, such as B-cell or T-cell. B-cell leukemia is the most common type. T-cell leukemia is much less common. Other types include Sézary syndrome, and hairy cell leukemia, a rare type of leukemia that produces abnormal white blood cells that, when viewed through a microscope, have hair-like projections.
The incidence of chronic lymphocytic leukemia increases with age - 90% of cases occur in people older than 50. By 70 years of age, 15 out of 100,000 people may have it. Men are two to three times more likely than women to develop the disease. Researchers believe that genetics plays a role in its development because it is rare in Japan and China, and remains uncommon in Japanese people who have moved to North America.
Causes
The cause of chronic lymphocytic leukemia is unknown. Unlike other forms of leukemia, there doesn't appear to be a relationship to radiation, carcinogenic chemicals (such as benzene), or viruses.
As mentioned above, there appears to be a hereditary factor in the development of the disease.
Symptoms
The symptoms of chronic lymphocytic leukemia usually develop gradually. Early in the disease, chronic lymphocytic leukemia generally has little effect on a person's well being. It may only be discovered after an abnormal blood count shows up during the course of a routine medical exam or while a person is being treated for an unrelated condition. Usually, an elevated white blood cell count will be the clue that leads the doctor to consider a diagnosis of chronic lymphocytic leukemia.
Key early symptoms include:
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swollen lymph nodes - painless swellings in the neck, armpits, or groin areas
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fatigue, mainly due to anemia
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fever
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infection
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loss of appetite and weight loss
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unusual bleeding
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night sweats
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pressure under the left ribs from enlargement of the spleen
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bone pain
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abnormal bruising (occurs later on)
Additional symptoms that may be associated with chronic lymphocytic leukemia include overall itching, side pain, and lumps in the armpit.
Chronic lymphocytic leukemia affects people in different ways. Usually, its progression is slow, and some people survive for many years, even without treatment. In others, it may progress more rapidly and earlier treatment may be required. It is difficult to predict individual circumstances, but there is about a 50% chance of surviving for six years, and a 25% chance of living 10 years after diagnosis.
People who have chronic lymphocytic leukemia seem to be more likely to develop other cancers. This is probably due to changes in their immune system.
Treatment
If chronic lymphocytic leukemia isn't at an advanced stage, your doctor may decide treatment is unnecessary at that point, and instead recommend "watchful waiting" and tracking the condition through regular blood testing. Treatment may not be needed for years, and then only if the number of lymphocytes increases, the lymph nodes enlarge, or the number of red blood cells or platelets decreases.
Chemotherapy may be used to treat some of the symptoms of chronic lymphocytic leukemia, such as fatigue, anemia, or enlarged lymph nodes. It may be necessary to receive blood or platelet transfusions, depending on the person's blood tests. Radiation is occasionally used to treat excessive lymph node enlargement.
If anemia develops, it's treated with blood transfusions and injections of epoetin* (a medication that stimulates red blood cell formation). Low platelet counts are treated with platelet transfusions, and infections with antibiotics. Sometimes the anemia or low platelet count is due to "autoimmune" effects, where the body's immune system attacks these blood components. This complication is often treated with high doses of steroids, intravenous gammaglobulins (a type of protein in the blood), and possibly surgical removal of the spleen.
Sometimes the spleen may be removed (splenectomy) if it has become very large and uncomfortable, or causes anemia as blood flows through it.
Over-treatment of leukemia with certain medications is actually more dangerous than under-treatment because they may cause severe side effects and don't cure the disease or allow people to live longer. Anticancer medications may be prescribed on their own or in combination with corticosteroids, such as prednisone, when the number of lymphocytes becomes very high. Corticosteroids can cause dramatic improvement in people with advanced leukemia. However, this improvement doesn't usually last long, and long-term use of corticosteroids can produce many negative effects, including an increased risk of getting severe infections.
New medications and new combinations of medications are currently being tested that may lead to better, more effective treatments for chronic lymphocytic leukemia, and new procedures for bone marrow transplants are also being studied.
Those who receive bone marrow transplants must take medications that suppress the body's immune system so that their bodies don't reject the new marrow. However, these medications also put the person at a much greater risk of infection, and ways to reduce this risk are under research.
Immunotherapy, which enhances the body's natural disease defenses, is a new area of research that shows promise. A variety of different treatments are being studied to boost the body's ability to prevent the growth and survival of leukemia cells.
Cytokines are another promising area of research. Cytokines are chemicals produced by the body to help cells communicate with each other. Researchers are looking for ways to make artificial cytokines that could help the immune system attack the leukemia cells.
As far as we know, there is nothing that can be done to prevent chronic lymphocytic leukemia. Early diagnosis and treatment is key to stopping the condition from getting worse.
*All medications have both common (generic) and brand names. The brand name
is what a specific manufacturer calls the product (e.g., Tylenol®).
The common name is the medical name for the medication (e.g., acetaminophen).
A medication may have many brand names, but only one common name. This article
lists medications by their common names. For more information on brand names,
speak with your doctor or pharmacist.
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Most cases of chronic lymphocytic leukemia are found through routine blood tests. Because it progresses very slowly with symptoms that develop gradually, it is often undiagnosed until routine blood tests show a high number of lymphocytes, or white blood cells.
Blood cells, and in most cases, bone marrow cells, must be examined in order to diagnose chronic lymphocytic leukemia. Blood analysis will show an increase in white blood cells. There may also be low platelet counts and red cell counts (anemia), but these are usually only slightly decreased in the early stages. A bone marrow examination may also show a large increase in the number of lymphocytes in the bone marrow, as well as a decrease in normal marrow cells.
If tests results are positive and your doctor diagnoses chronic lymphocytic leukemia, further tests need to take place to establish what subtypes of white blood cells have been affected. The results of these tests will help predict how rapidly or slowly the disorder may advance and will determine what kind of treatment, if any, should be started.
In addition, a sample of marrow, taken by biopsy, may be examined to check for abnormalities in chromosomes. This analysis, referred to as cytogenetics analysis, determines whether there are abnormal chromosomes.
Further blood tests may be done to determine associated abnormalities in blood proteins and immune function that may help to predict possible future complications such as anemia, bleeding, or infection.
The doctor will determine how far the chronic lymphocytic leukemia has progressed (staging). This will help predict the severity of the condition and guide treatment. Staging is based on factors such as the number of lymphocytes in the blood and bone marrow, size of the spleen and liver, the presence or absence of anemia, and platelet count. Usually, death occurs because the bone marrow can't produce enough normal cells to carry oxygen, fight infections, and prevent bleeding.
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