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, or chronic lymphoid leukemia (CLL), is one of several different types of leukemia. 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.
The incidence of chronic lymphocytic leukemia increases with age, where 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 Asian countries such as Japan and China, and it remains uncommon in Japanese people who have moved to North America. This condition is more common in Caucasians, followed by people of African descent, Hispanics, and First Nations.
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, family history and age are risk factors for developing this disease.
Symptoms and Complications
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:
- swollen lymph nodes – painless swellings in the neck, armpits, or groin areas
- fatigue, mainly due to anemia
- frequent infections
- loss of appetite and weight loss
- unusual bleeding and bruising (tends to occur later than earlier)
- night sweats
- pressure under the left ribs from enlargement of the spleen
- bone pain
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.
Some people with chronic lymphocytic leukemia may develop complications such as autoimmune hemolytic anemia (low red blood cells due to body attacking its own red blood cells), immune thrombocytopenia (low platelets due to body destroying its own platelets), and infections. People who have chronic lymphocytic leukemia also seem to be more likely to develop other cancers. This is probably due to changes in their immune system.
Making the Diagnosis
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 must be examined in order to diagnose chronic lymphocytic leukemia. A routine blood count will show an increase in white blood cells, and a test called flow cytometry will identify this increased population of cells as being cancerous.There may also be low platelet counts and red cell counts (anemia), but these are usually only slightly decreased in the early stages.
If test results are positive and your doctor diagnoses chronic lymphocytic leukemia, further tests need to take place to establish what specific types 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.
Further blood tests may be done to determine associated genetic abnormalities in the leukemic cells, which may help predict prognosis and guide therapy.
The doctor will determine how far the chronic lymphocytic leukemia has progressed. This is known as 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 when the bone marrow can't produce enough normal cells to carry oxygen, fight infections, and prevent bleeding.
Treatment and Prevention
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. Blood tests are performed every 3 months, and at the end of 12 months the medical team will re-evaluate the treatment plan. 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. Another treatment option is biologic therapy, which uses a class of medications that help your body's immune system to fight cancer cells.
If anemia develops, it's treated with blood transfusions and injections of erythropoiesis stimulating agents (medications that stimulate 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.
Bone marrow transplant is an option usually for younger people with severe acute leukemia disease. 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 greater risk for infection. Ways to reduce this risk are under research.
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. Often, it is recommended for people with CLL to enroll in a well-conducted clinical trial in order to receive the most current treatment.
As far as we know, there is nothing that can be done to prevent chronic lymphocytic leukemia.
*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 information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist.
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