Chronic lymphocytic leukemia (CLL) is a type of cancer of the blood and bone marrow — the spongy tissue inside bones where blood cells are made.
The term “chronic" in chronic lymphocytic leukemia comes from the fact that it typically progresses more slowly than other types of leukemia. The term “lymphocytic" in chronic lymphocytic leukemia comes from the cells affected by the disease — a group of white blood cells called lymphocytes, which help your body fight infection.
Chronic lymphocytic leukemia most commonly affects older adults. There are treatments to help control the disease.
Many people with chronic lymphocytic leukemia (CLL) do not have any symptoms when it is diagnosed. The leukemia is often found when their doctor orders blood tests for some unrelated health problem or during a routine check-up and they are found to have a high number of lymphocytes.
Even when people with CLL have symptoms, they're often vague and can be symptoms of other things. Symptoms can include the following:
Many of the signs and symptoms of advanced CLL occur because the leukemia cells replace the bone marrow's normal blood-making cells. As a result, people don't have enough red blood cells, properly functioning white blood cells, and blood platelets.
Anemia is a shortage of red blood cells. It can cause tiredness, weakness, and shortness of breath.
A shortage of normal white blood cells (leukopenia) increases the risk of infections. You might hear the term neutropenia, which refers to low levels of neutrophils (a type of granulocyte needed to fight bacterial infections). People with CLL may have very high white blood cell counts because of excess numbers of lymphocytes (lymphocytosis), but the leukemia cells don't fight infection the way normal white blood cells do.
A shortage of blood platelets (thrombocytopenia) can lead to excess bruising, bleeding, frequent or severe nosebleeds, and bleeding gums.
People with CLL have a higher risk of infections. This is mainly because their immune systems aren't working as well as they should. CLL is a cancer of B lymphocytes, which normally make antibodies that help fight infection. Because of the CLL, these antibody-making cells don't work as they should, so they can't fight infections. Infections may range from simple things like frequent colds or cold sores to pneumonia and other serious infections.
CLL can also affect the immune system in other ways. In some people with CLL, the immune system cells make abnormal antibodies that attack normal blood cells. This is known as autoimmunity. It can lead to low blood counts. If the antibodies attack red blood cells, it's called autoimmune hemolytic anemia. Less often, the antibodies attack platelets and the cells that make them, leading to low platelet counts. Rarely, the antibodies attack white blood cells, leading to leukopenia (low white blood cell counts).
These symptoms and signs may be caused by CLL, but they can also be caused by other conditions. Still, if you have any of these problems, it's important to see a doctor right away so the cause can be found and treated, if needed.
Doctors aren't certain what starts the process that causes chronic lymphocytic leukemia. What's known is that something happens to cause a genetic mutation in the DNA of blood-producing cells. This mutation causes the blood cells to produce abnormal, ineffective lymphocytes.
Beyond being ineffective, these abnormal lymphocytes continue to live and multiply, when normal lymphocytes would die. The abnormal lymphocytes accumulate in the blood and certain organs, where they cause complications. They may crowd healthy cells out of the bone marrow and interfere with normal blood cell production.
Doctors and researchers are working to understand the exact mechanism that causes chronic lymphocytic leukemia.
A risk factor is something that affects a person's chance of getting a disease like cancer. Different cancers have different risk factors. Some risk factors, like smoking, can be changed. Others, like a person’s age or family history, can’t be changed.
But risk factors don't tell us everything. Having a risk factor, or even many risk factors, doesn’t mean that you will get the disease. And some people who get the disease may not have had any known risk factors. Even if a person has a risk factor and develops cancer, it's often very hard to know how much that risk factor may have contributed to the cancer.
There are very few known risk factors for chronic lymphocytic leukemia (CLL). These include:
Your age: This disease occurs most often in older adults. On average, people diagnosed with chronic lymphocytic leukemia are in their 70s.
Your race: Whites are more likely to develop chronic lymphocytic leukemia than are people of other races.
Family history of blood and bone marrow cancers: A family history of chronic lymphocytic leukemia or other blood and bone marrow cancers may increase your risk.
Exposure to chemicals: Certain herbicides and insecticides, including Agent Orange used during the Vietnam War, have been linked to an increased risk of chronic lymphocytic leukemia.
Chronic lymphocytic leukemia may cause complications such as:
Frequent infections: People with chronic lymphocytic leukemia may experience frequent infections. In most cases, these infections are common infections of the upper and lower respiratory tract. But sometimes more-serious infections can develop.
A switch to a more aggressive form of cancer: A small number of people with chronic lymphocytic leukemia may develop a more aggressive form of cancer called diffuse large B-cell lymphoma. Doctors sometimes refer to this as Richter's syndrome.
Increased risk of other cancers: People with chronic lymphocytic leukemia have an increased risk of other types of cancer, including skin cancer, such as melanoma, and cancers of the lung and the digestive tract.
Immune system problems: A small number of people with chronic lymphocytic leukemia may develop an immune system problem that causes the disease-fighting cells of the immune system to mistakenly attack the red blood cells or the platelets.
Tests and procedures used to diagnose chronic lymphocytic leukemia include blood tests designed to:
Count the number of cells in a blood sample: A complete blood count may be used to count the number of lymphocytes in a blood sample. A high number of B cells, one type of lymphocyte, may indicate chronic lymphocytic leukemia.
Determine the type of lymphocytes involved: A test called flow cytometry or immunophenotyping helps determine whether an increased number of lymphocytes is due to chronic lymphocytic leukemia, a different blood disorder or your body's reaction to another process, such as infection.
If chronic lymphocytic leukemia is present, flow cytometry may also help analyze the leukemia cells for characteristics that help predict how aggressive the cells are.
Analyze lymphocytes for genetic abnormalities: A test called fluorescence in situ hybridization (FISH) examines the chromosomes inside the abnormal lymphocytes to look for abnormalities. Doctors sometimes use this information to determine your prognosis and help choose a treatment.
In some cases, your doctor may order additional tests and procedures to aid in diagnosis, such as:
Your treatment options for chronic lymphocytic leukemia depend on several factors, such as the stage of your cancer, whether you're experiencing signs and symptoms, your overall health, and your preferences.
Treatment may not be necessary in early stages
People with early-stage chronic lymphocytic leukemia typically don't receive treatment. Studies have shown that early treatment doesn't extend lives for people with early-stage chronic lymphocytic leukemia.
Rather than put you through the potential side effects and complications of treatment before you need it, doctors carefully monitor your condition and reserve treatment for when your leukemia progresses. Doctors call this watchful waiting.
Your doctor will plan a checkup schedule for you. You may meet with your doctor and have your blood tested every few months to monitor your condition.
Treatment for people with early-stage chronic lymphocytic leukemia is offered only through clinical trials. Studies that evaluate whether early treatment may be helpful might be an option for people with early-stage disease that has a high risk of progression. Talk to your doctor about your options.
Treatments for intermediate and advanced stages
Your doctor uses the stage of your chronic lymphocytic leukemia, results from various tests —including laboratory analysis of your cancer cells — and your overall health to make recommendations about your treatment.
If your doctor determines your chronic lymphocytic leukemia is progressing or is in the intermediate or advanced stages, your treatment options may include:
Chemotherapy: Chemotherapy is a drug treatment that kills quickly growing cells, including cancer cells. Chemotherapy treatments can be administered through a vein or taken in pill form. Depending on your situation, your doctor may use a single chemotherapy drug or you may receive a combination of drugs.
Targeted drug therapy: Targeted drugs are designed to take advantage of the specific vulnerabilities of your cancer cells. Your cancer cells are tested to determine which targeted drugs may be helpful.
Immunotherapy: Immunotherapy is a treatment that uses your body's immune system to fight cancer. Immunotherapy treatments may make it easier for your immune system to identify cancer cells or train your immune system cells to fight cancer cells.
Bone marrow transplant: A bone marrow transplant, also known as a stem cell transplant, uses strong chemotherapy drugs to kill the stem cells in your bone marrow that are creating diseased lymphocytes. Then healthy adult blood stem cells from a donor are infused into your blood, where they travel to your bone marrow and begin making healthy blood cells.
As new and more-effective drug combinations have been developed, bone marrow transplant has become less common in treating chronic lymphocytic leukemia. Still in certain cases, this may be a treatment option.
Treatments may be used alone or in combination with each other.