Chronic lymphocytic leukemia (CLL) is a type of cancer in which the bone marrow makes too many lymphocytes (a type of white blood cell).

CLL is a cancer of the blood and bone marrow that usually gets worse slowly. CLL is one of the most common types of leukemia in adults. It often occurs during or after middle age; it rarely occurs in children.

Leukemia may affect red blood cells, white blood cells, and platelets.

Normally, the bone marrow makes blood stem cells (immature cells) that become mature blood cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell.

A myeloid stem cell becomes one of three types of mature blood cells:

• Red blood cells that carry oxygen and other substances to all tissues of the body.
• Granulocytes, which are white blood cells that help fight infection and disease.
• Platelets that form blood clots to stop bleeding.

A lymphoid stem cell becomes a lymphoblast cell and then one of three types of lymphocytes (white blood cells):

• B lymphocytes that make antibodies to help fight infection.
• T lymphocytes that help B lymphocytes make the antibodies that help fight infection.
• Natural killer cells that attack cancer cells and viruses.

In CLL, too many blood stem cells become abnormal lymphocytes. The abnormal lymphocytes may also be called leukemia cells. These leukemia cells are not able to fight infection very well. Also, as the number of leukemia cells increases in the blood and bone marrow, there is less room for healthy white blood cells, red blood cells, and platelets. This may lead to infection, anemia, and easy bleeding.

Signs and symptoms of CLL include swollen lymph nodes and feeling tired.

In the beginning, CLL does not cause any signs or symptoms and may be found during a routine blood test. Later, signs and symptoms may occur. Check with your doctor if you have:

• Painless swelling of the lymph nodes in the neck, underarm, stomach, or groin.
• Weakness or feeling tired.
• Pain or a feeling of fullness below the ribs.
• Fever and infection.
• Easy bruising or bleeding.
• Petechiae (flat, pinpoint, dark-red spots under the skin caused by bleeding).
• Weight loss for no known reason.
• Drenching night sweats.

Tests that examine the blood are used to diagnose CLL.

In addition to asking about your personal and family health history and doing a physical exam, your doctor may perform the following tests and procedures:

• Complete blood count (CBC) with differential: A procedure in which a sample of blood is drawn and checked for:
  • The number of red blood cells and platelets.
  • The number and type of white blood cells.
  • The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
  • The portion of the blood sample made up of red blood cells.
  
• Blood chemistry studies: A procedure in which 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.
• Lactate dehydrogenase testing: A laboratory test for one of a group of enzymes found in the blood and other body tissues and involved in energy production in cells. An increased amount of lactate dehydrogenase in the blood may be a sign of tissue damage and some types of cancer or other diseases.
• Beta-2-microglobulin testing: A laboratory test for beta-2-microglobulin, a small protein normally found on the surface of many cells, including lymphocytes, and in small amounts in the blood and urine. An increased amount in the blood or urine may be a sign of certain diseases, including some types of cancer, such as multiple myeloma or lymphoma.
• Flow cytometry: A laboratory test that measures the number of cells in a sample, the percentage of live cells in a sample, and certain characteristics of the cells, such as size, shape, and the presence of tumor (or other) markers on the cell surface. The cells from a sample of a patient’s blood, bone marrow, or other tissue are stained with a fluorescent dye, placed in a fluid, and then passed one at a time through a beam of light. The test results are based on how the cells that were stained with the fluorescent dye react to the beam of light. This test is used to help diagnose and manage certain types of cancers, such as leukemia and lymphoma.
• FISH (fluorescence in situ hybridization): A laboratory test used to look at and count genes or chromosomes in cells and tissues. Pieces of DNA that contain fluorescent dyes are made in the laboratory and added to a sample of a patient’s cells or tissues. When these dyed pieces of DNA attach to certain genes or areas of chromosomes in the sample, they light up when viewed under a fluorescent microscope. The FISH test is used to help diagnose cancer and help plan treatment.
• Genetic testing: A laboratory test in which cells or tissue are analyzed to look for changes in the TP53 or IGH gene. These changes may be helpful to determine the patient's prognosis.
• Serum immunoglobulin testing: A laboratory test that measures specific types of immunoglobulins (antibodies) in the blood. This may help diagnose cancer or find out how well treatment is working or if cancer has come back.
• Hepatitis B virus and hepatitis C virus testing: A test to check for hepatitis B or hepatitis C virus in the blood. Infection with one of these viruses causes hepatitis (inflammation of the liver).
• HIV testing: A test to check for HIV infection. HIV is the virus that causes AIDS. The most common type of HIV test is called the HIV antibody test, which checks for antibodies against HIV in a sample of blood, urine, or fluid from the mouth.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis depends on:

• Whether there are certain gene changes, such as in TP53 or IGH.
• Whether lymphocytes have spread throughout the bone marrow.
• Whether the red blood cell and platelet counts are low.
• Whether the white blood cell count is increasing quickly.
• The stage of the cancer.
• The results of certain blood tests, such as the beta-2 microglobulin and lactate dehydrogenase tests.
• The patient's age and general health.
• How quickly and how low the leukemia cell count drops during treatment.
• Whether the CLL gets better with treatment or has recurred (come back).
• Whether the CLL progresses to lymphoma or becomes prolymphocytic leukemia.
• Whether the patient gets another type of cancer after being diagnosed with CLL.

Treatment options depend on:

• The red blood cell, white blood cell, and platelet blood counts.
• Whether the liver, spleen, or lymph nodes are larger than normal.
• The age and health of the patient at the time of diagnosis.
• Whether there are signs or symptoms, such as fever, chills, or weight loss.
• The response to initial treatment.
• Whether the CLL has recurred (come back).