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What is Chronic Lymphocytic Leukemia?

Chronic lymphocytic leukemia (CLL), sometimes referred to as lymphoblastic leukemia, is a type of cancer that causes the body to produce large numbers of white blood cells. These cells, called lymphocytes, cannot fight infection very well.

When leukemia cells build up in the blood and bone marrow, there is less room for healthy blood cells. This can cause infections, anemia, and easy bleeding. CLL usually advances slowly and occurs more frequently in adults in their 60s. It is more common in men than women, and is rarely seen in children.

Our approach

Northwell Health Cancer Institute is home to one of the largest leukemia programs in the nation. Our nationally recognized physicians have extensive experience with hematologic malignancies and work collaboratively with experts in pathology and genomics to make a definitive diagnosis and identify the most appropriate therapies. Your dedicated team also includes specialized nursing staff, social workers, nutritionists and other specialists who ensure you’re obtaining the best possible care based on your diagnosis and needs. Our center also has a dedicated leukemia floor at North Shore University Hospital and a research center specifically for CLL, where we are currently conducting extensive research to uncover the causes of the disease. This is leading to more clinical capabilities for treatment. 

Highlights of our CLL treatments and services include:

  • Personalized CLL treatments from a team of physicians with extensive experience with hematologic malignancies, particularly CLL
  • Expert management of less common chronic leukemias of lymphocytes, including prolymphocytic and hairy cell leukemia
  • Advanced therapies that deliver the best outcomes with the least impact on the body, including clinical trials sponsored by the National Cancer Institute

Research at Northwell

Through collaboration with leading research laboratories, you may have the opportunity to participate in clinical trials as part of your treatment for CLL. While not every patient is a candidate for clinical trials, your care team will work with you to determine eligibility. Learn more about clinical trials at Northwell Health.


The early signs of CLL and other chronic leukemias of lymphocytes may be like the flu or other common diseases, including:

  • Painless swelling of the lymph nodes in the neck, underarm, stomach or groin
  • Feeling very tired
  • Pain or fullness below the ribs
  • Fever and infection
  • Weight loss for no known reason

It is important to note that these symptoms could be due to conditions other than chronic lymphocytic leukemia. The Northwell Cancer Institute offers state-of-the-art testing for CLL. If diagnosed with the disease, your treatment regimen needs will be based on findings from tests used during diagnosis.

Risk factors

The cause of CLL is unknown. Unlike some other forms of cancer, there is no evidence that exposure to chemicals, radiation or chemotherapy can cause it. Known risk factors for CLL include:

  • Family history—Individuals with a first-degree relative with CLL are at a higher risk of developing the disease.
  • Age—CLL is most common in adults older than 50.
  • Gender—CLL is more common in men.
  • Race/ethnicity—CLL is more common in people of African, European or Russian ancestry. It is rare in individuals of Asian ancestry.
  • Monoclonal B-cell lymphocytosis—CLL is more common in individuals who have higher levels of lymphocytes.


The first step to making a chronic lymphocytic leukemia diagnosis is usually a physical exam. The doctor will also consider personal and family medical history. If chronic lymphocytic leukemia is suspected, you will be sent for additional tests—usually administered on an outpatient basis—which include:

  • Complete blood count (CBC) with differential—Blood is drawn to measure the number of red blood cells, white blood cells and platelets in the blood. The amount of hemoglobin (substance in the blood that carries oxygen) and the hematocrit (the amount of whole blood that is made up of red blood cells) are also measured. The differential will count the different types of white blood cells that may be present.
  • Peripheral blood smear—A blood sample is checked for the number and kinds of white blood cells, the number of platelets and changes in the shape of blood cells.
  • Bone marrow aspiration and biopsy — A small sample of bone marrow and bone is removed. The sample is examined by a pathologist for signs of leukemia.
  • Immunophenotyping—A process used to identify cells, based on the types of antigens or proteins on the surface of the cell. This process is used to diagnose specific types of leukemia and lymphoma by comparing cancer cells to their normal counterparts. Flow cytometry and immunohistochemistry are the two tests used to provide optimal immunophenotyping.
  • Blood chemistry studies—A blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.
  • Cytogenetic analysis—The chromosomes in the cells of a blood or bone marrow sample are examined. Abnormalities in the chromosomes could be a sign of leukemia. Cytogenetics and a related procedure called fluorescence in-situ hybridization (FISH) are used to identify whether or not abnormal chromosomes are present.
  • Molecular genetics—The molecular genetics laboratory looks for expressions of disease that may have escaped detection by other methods.
  • Chest X-rays—X-rays help doctors look for tumors in the chest and lungs or evidence of infection.
  • CT or CAT scan (computerized axial tomography)—More detailed than an x-ray, this procedure uses a combination of x-rays and computer technology to produce detailed images if needed.
  • MRI (magnetic resonance imaging)—A powerful magnet, radio waves and computer imaging combine to create highly detailed pictures of areas inside the body, if needed.
  • PET scan (positron emission tomography)—Small amounts of radioactive sugar are injected to highlight cancers and areas of infection and inflammation.

Treatment types

Chronic lymphocytic leukemia requires accurate diagnosis and expert treatment. For some patients with CLL, immediate treatment is not necessary. Instead, the disease is monitored carefully without active treatment, known as active surveillance. Other patients require immediate treatment. Treatment is recommended for patients with symptoms or worsening blood counts.

Treatments include:

  • Chemotherapy—Administered by a medical oncologist, chemotherapy is usually given orally or via an intravenous (IV) tube placed into a vein. In some cases, chemotherapy is combined with a stem cell transplant. There are two types of stem cell transplants. Allogenic stem cell plants use donated stem cells, and autologous use your own stem cells. The goal of this treatment is to destroy all of the cancer cells in the bone marrow, blood and other parts of the body using high doses of chemotherapy and then replace blood stem cells to create healthy bone marrow.
  • Radiation therapy—Radiation therapy is not commonly used to treat CLL because the disease is located throughout the body. However, it is sometimes used to treat certain symptoms, such as an enlarged spleen or swollen lymph nodes.

Living with

  • You may get medicine for nausea, vomiting, or pain (although leukemia rarely causes pain). Take your medicines exactly as prescribed. Call your doctor if you think you are having a problem with your medicine. You will get more details on the specific medicines your doctor prescribes.
  • Eat healthy food. If you do not feel like eating, try to eat food that has protein and extra calories to keep up your strength and prevent weight loss. Drink liquid meal replacements for extra calories and protein. Try to eat your main meal early.
  • Get some physical activity every day, but do not get too tired. Keep doing the hobbies you enjoy as your energy allows.
  • Take steps to control your stress and workload. Learn relaxation techniques.
    • Share your feelings. Stress and tension affect our emotions. By expressing your feelings to others, you may be able to understand and cope with them.
    • Consider joining a support group. Talking about a problem with your spouse, a good friend, or other people with similar problems is a good way to reduce tension and stress.
    • Express yourself through art. Try writing, dance, art, or crafts to relieve tension. Some dance, writing, or art groups may be available just for people who have cancer.
    • Be kind to your body and mind. Getting enough sleep, eating a nutritious diet, and taking time to do things you enjoy can contribute to an overall feeling of balance in your life and help reduce stress.
    • Get help if you need it. Discuss your concerns with your doctor or counselor.
  • If you are vomiting or have diarrhea:
    • Drink plenty of fluids (enough so that your urine is light yellow or clear like water) to prevent dehydration. Choose water and other caffeine-free clear liquids. If you have kidney, heart, or liver disease and have to limit fluids, talk with your doctor before you increase the amount of fluids you drink.
    • When you are able to eat, try clear soups, mild foods, and liquids until all symptoms are gone for 12 to 48 hours. Other good choices include dry toast, crackers, cooked cereal, and gelatin dessert, such as Jell-O.
  • Avoid colds and flu. Get a pneumococcal vaccine shot. If you have had one before, ask your doctor whether you need another dose. Get a flu shot every year. If you must be around people with colds or flu, wash your hands often.
  • Do not smoke. If you need help quitting, talk to your doctor about stop-smoking programs and medicines. These can increase your chances of quitting for good.
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