Chronic lymphocytic leukemia is cancer of the white blood cells (lymphocytes).

Chronic lymphocytic leukemia (CLL) causes a slow increase in the number of B lymphocytes in the bone marrow. The cancerous cells spread from the blood marrow to the blood, and can also affect the lymph nodes and other organs. CLL causes the bone marrow to fail and weakens the immune system.

The reason for this increase in B lymphocytes is unknown. There is no link to radiation, cancer-causing chemicals, or viruses.

Usually, the symptoms develop gradually. Many cases are detected by routine blood tests in people with no symptoms.

CLL primarily strikes adults. The average age of a patient with this type of leukemia is 70. It is rarely seen in people younger than 40. The disease is more common in Jewish people of Russian or East European descent, and is uncommon in Asia.

• Enlarged lymph nodes, liver, or spleen
• Fatigue
• Abnormal bruising (occurs late in the disease)
• Excessive sweating, night sweats
• Loss of appetite
• Unintentional weight loss

Patients with CLL have a higher-than-normal white blood cell count.

Tests to diagnose CLL include:

• CBC
• Flow cytometry
• Bone marrow aspiration
• Serum protein electrophoresis

If your doctor discovers you have CLL, tests will be done to see how much the cancer has spread. This is called staging. There are two methods to stage CLL.

There are different ways to stage CLL. One system uses numbers to group CLL into low-, intermediate-, and high-risk categories. Generally, the higher the stage number, the more advanced the cancer. Another system uses letters to stage CLL according to how many lymph node groups are affected and whether or not you have a drop in red blood cells and platelets.