Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia, also referred to as CLL, is a form of cancer in which lymphocytes are affected. Lymphocytes are an important part of the immune system and they protect the body against all infections. They are a type of white blood cells (WBCs). Lymphocytes can be classified into T cells, B cells and natural killer cells (NK cells). In 80% cases of CLL, B cells are affected. Lymphocytes originate in the bone marrow, develop in the lymph nodes and they have a definite lifespan. In CLL, the DNA of lymphocytes are damaged when they are produced in the bone marrow. These damaged lymphocytes look normal and live for a long span of time; however, they are unable to function properly. Gradually, these damaged cells grow in number and replace the normal lymphocytes, thus weakening the immune system. Uncontrolled growth of lymphocytes causes chronic lymphocytic leukemia.

Risk Factors of Chronic Lymphocytic Leukemia

The exact cause of chronic lymphocytic leukemia remains unknown, but certain risk factors are said to be associated with it. Some of these risk factors are listed below.

• Age: CLL cases are mostly found in people who are above 60 years; only 20% of the CLL cases are seen in people below 40 years.
• Race: Asians are less susceptible to CLL, as compared to Europeans and North Americans.
• Sex: CLL is more common in males than in females, the reason for which is still unknown.
• Family History: Chances of CLL increase, if any blood relative has suffered from the disease.

Symptoms of Chronic Lymphocytic Leukemia

Usually, a CLL patient does not show any symptoms in the early stages. However, the patient can show the following symptoms in the later stages.

• Infection: Since the immune system of the CLL patient does not function properly, he/she may be susceptible to infections.
• Anemia: Symptoms of anemia include weakness and pale look, due to reduced RBC count.
• Abnormal Bruising and Bleeding: Due to reduced platelet count.
• Swelling: The lymph glands may swell without causing any pain. Swellings may occur in the neck or armpits and spleen.
• Other symptoms: Some patients may show symptoms like sweating or high body temperature, while some may lose weight.

Diagnosis of Chronic Lymphocytic Leukemia

Since CLL does not show symptoms in the early stages, it is mostly detected during routine blood tests. Following are some of the tests performed by the pathologist to diagnose CLL.

• CBC: It's the complete blood count, wherein the number of RBCs, WBCs, platelets and hemoglobin are checked. Very high elevation in the WBC count needs further tests for accurate diagnosis of CLL.
• Cytogenic Analysis: In this test, the structure of the lymphocytes is examined with the help of a microscope.
• Bone Marrow Aspiration: Bone marrow samples are taken either from the hipbone or the breastbone. This test is usually done to confirm the diagnosis.
• Lymph Node Biopsy: In rare cases, a biopsy may be performed in case the patient has an enlarged lymph node.

The above tests help in determining the severity (or stage) of CLL and thereby, help in deciding the appropriate treatment.

Staging of Chronic Lymphocytic Leukemia

Staging is a term used for all cancer diseases. It is done to check the severity of the cancer. In CLL, Ria and Binet systems are the two staging techniques that are used. Staging of CLL depends on the number of abnormal lymphocytes in the blood.

Ria System

• Stage 0: Increase in lymphocyte count (5,000 or 10,000 lymphocytes/mm³of blood), normal RBC and platelet count, but no swelling in lymph nodes, liver or spleen.
• Stage 1: Increase in lymphocyte count and swelling of lymph nodes. Normal RBC and platelet count.
• Stage 2: Increase in lymphocyte count, swelling of lymph node and spleen. Liver may or may not be swollen. Normal RBC and platelet count.
• Stage 3: Increase in lymphocyte count and reduction in RBC (anemia). Lymph node, liver or spleen may or may not be swollen. Normal platelet count.
• Stage 4: All the observations of Stage 0 to Stage 3 plus reduced platelet count.

Binet System

• Stage A: Maximum 3 lymphoid areas are enlarged (lymphoid tissues are rich in lymphocytes). Normal RBC and platelet count.
• Stage B: Minimum 3 lymphoid areas are enlarged. Normal RBC and platelet count.
• Stage C: Reduced RBC and platelet count.

These staging techniques prove to be useful in giving appropriate treatment to the CLL patient.

Treatment for Chronic Lymphocytic Leukemia

CLL is not a curable disease, but treatment can help the patient lead a normal life. Treatment for CLL is necessary only in severe or intermediate stages; in the early stages, it is not useful and may have side effects.

Treatment for CLL is totally dependent on the results of the staging techniques. Following are some of the treatments for a CLL patient:

• Chemotherapy uses anti-cancer drugs that kill abnormal lymphocytes. These anti-cancer drugs may be in a tablet form or can be injected. Chemotherapy has side effects, like hair loss, vomiting, nausea, etc. These side effects end, when the treatment is finished. Steroids are sometimes used along with chemotherapy medication.
• Monoclonal antibodies may be used as treatment for CLL. They are proteins which attach to the immature cells and destroy them without affecting normal cells.
• Radiotherapy is used, in cases, when the CLL patient has an enlarged lymph node or spleen. In this treatment, high radiation is used to destroy the immature cells.
• Bone marrow transplant may be advised to control the disease in younger patients.

A CLL patient can live long, even after the disease is diagnosed. Patients at stage A can live for more than 10 years, after diagnosis. CLL is mostly detected after the age of 60, and it progresses very slowly.