Non-Hodgkin's lymphoma is cancer that starts in the lymphoid tissue. Such tissue makes up the lymph nodes, spleen, and other organs of the immune system.

White blood cells called lymphocytes are found in lymph tissues. Most lymphomas start in a type of white blood cells called B lymphocytes, or B cells.

For most patients, the cause of the cancer is unknown. However, lymphomas may develop in people with weakened immune systems. For example, the risk of lymphoma increases after an organ transplant.

Non-Hodgkin's lymphoma is classified according to how fast the cancer spreads. The cancer may be low grade, intermediate grade or high grade. Burkitt's tumor is an example of a high-grade lymphoma. There are many different types of non-Hodgkin's lymphoma.

According to the American Cancer Society, a person has a 1 in 50 chance of developing non-Hodgkin's lymphoma. Most of the time, this cancer affects adults. However, children can get some forms of lymphoma. High-risk groups include those who have received an organ transplant or who have a weakened immune system (immunosuppression). The cancer is more common in men than women.

Non-Hodgkin's lymphoma can cause a variety of symptoms. Symptoms depend on what area of the body is affected by the cancer. Symptoms may include:

• Swollen lymph nodes in the neck, underarms, groin, or other areas
• Fever
• Excessive sweating, especially with night sweats
• Unintentional weight loss
• Severe itchiness

Coughing or shortness of breath may occur if the cancer affects the thymus gland or lymph nodes in the chest, which puts pressure on the windpipe.

Some patients may have stomach pain or swelling, which may lead to a loss of appetite, constipation, nausea, and vomiting.

If the cancer affects cells in the brain, the person may have a headache, concentration problems, personality changes, or seizures.

The doctor will perform a physical exam and feel lymph nodes to see if they are swollen. Tests to diagnose and stage non-Hodgkin's lymphoma include:

• Lymph node biopsy
• Bone marrow biopsy
• CBC with differential
• CT scans of the chest, abdomen and pelvis
• Blood chemistry tests
• X-rays
• PET (positron emission tomography) scan

Treatment depends on how quickly the cancer spreads, the stage of the cancer when you are first diagnosed, and symptoms.

Chemotherapy is commonly used. A drug called rituximab (Rituxan) is often used to treat non-Hodgkin's lymphoma. Rituxan is a form of immunotherapy.

Radioimmunotherapy may be used in some cases. This involves linking a radioactive substance with an antibody that helps the immune system fight infection, and injecting the substance into the body.

In select cases, a stem cell transplant may be needed.

The stress of illness may be eased by joining a support group whose members share common experiences and problems.

See: Cancer - support group

Low-grade non-Hodgkin's lymphoma can not be cured with chemotherapy. However, the low-grade form of this cancer progresses slowly, and it may take more than 10 years before the disease gets worse.

Chemotherapy can help cure high-grade lymphoma. However, if the cancer does not respond to chemotherapy drugs, the disease can cause rapid death.

• Infection
• Autoimmune hemolytic anemia

Call your health care provider if symptoms of this disorder develop.

If you have non-Hodgkin's lymphoma, call your health care provider if you experience persistent fever or other signs of infection.

Goldman L, Ausiello D, eds. Cecil Textbook of Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:pp. 1408-1419.