What is non-Hodgkin's lymphoma?

Non-Hodgkin's lymphoma is cancer of the lymphatic system, the body's immune system. In part, the lymphatic system is composed of lymph nodes, which are small, spherical clusters of lymphocytes, or white blood cells. In a healthy immune system, lymphocytes have a normal cycle of life-they are produced regularly and die off regularly. But in the immune systems of people with non-Hodgkin's lymphoma, abnormal lymphocytes emerge and divide uncontrollably and at an alarming rate, overcrowding the lymph nodes and impairing their functions.

This type of cancer accounts for about 5 percent of all cancer cases in the United States and can spread to anywhere in the body, including the bone marrow, liver, spleen, or other organs.

What are the causes of non-Hodgkin's lymphoma?

Researchers are not sure what causes Non-Hodgkin's lymphoma, but many believe that it is fueled by the activation of faulty (or injured) DNA found in the body's B lymphocytes. Lymphocytes are classified as either B or T cells, depending on their origins. Those produced in the bone marrow are called B cells; those derived from the thymus are labeled T cells. B cells cultivate plasma cells, which produce antibodies intended to abrogate foreign attackers, while T cells kill invaders directly. Roughly 85 percent of non-Hodgkin's cancers originate in B lymphocytes; T cells are to blame for the remaining 15 percent.

What are the symptoms of non-Hodgkin's lymphoma?

Non-Hodgkin's lymphoma is usually signaled by tender, swollen lymph nodes in the groin, neck, or armpit and less frequently, in the elbow, throat, and ears. A person with the disease may also experience fevers, excessive sweating (usually at night), weight loss or gain, fatigue, loss of appetite, or an enlarged spleen. Less often, non-Hodgkin's lymphoma originates somewhere other than the lymph nodes, such as in the skin, a bone, or a lung. In such cases, symptoms may be localized-chest pain, skin masses, coughs, bone pain, or rashes are the norm. But typically, swollen lymph nodes are the only sign of the disease.

It is important to note that most enlarged lymph nodes are attributed to infection, not cancer. Further testing-such as a biopsy-for cancer may be performed only if no signs of infection are present.

What are the treatments for non-Hodgkin's lymphoma?

The way in which lymphoma is treated depends on the patient's age, health, and stage of disease. More than one type of treatment is often administered. Options include:

• Chemotherapy-In chemotherapy, a personalized combination of drugs is either injected or swallowed to fight rapid cancer cell growth. The amount of drugs or doses is determined by the grade of lymphoma-usually one drug is used to treat low-grade lymphoma, and multiple drugs are used for intermediate- or high-grade lymphoma.
• Radiation-High doses of radiation are administered to shrink cancerous cells and tumors. This type of treatment is usually reserved for low-grade, early-stage lymphoma and is sometimes used in conjunction with chemotherapy.
• Stem Cell Transplantation-With stem-cell transplantation, healthy stem cells are drawn from the patient's blood or marrow and frozen; after chemotherapy is administered, the healthy stem cells are injected back into the patient's body. Such treatment is typically used to treat patients who have relapsed after successful treatment of intermediate- to high-grade lymphomas.
• Observation-In cases of slow-progressing lymphoma, doctors sometimes observe the patient and patterns of cancer growth for up to or longer than a year before choosing a treatment option.
• Immunotherapy - Rituximab (Rituxan) - Rituxan was the first monoclonal antibody drug approved by the FDA (1997) for the treatment of non-Hodgkin's lymphoma. The immunotherapy drug works by targeting and killing all "B-cells" (a type of white blood cell) in the blood and lymph nodes. Rituxan treatments last between four and eight weeks and can be used in patients who have undergone other forms of treatment unsuccessfully.
• Radioimmunotherapy - Tositumomab (Bexxar) - Radioimmunotherapy is a promising new therapeutic regimen that combines radiation therapy with immunotherapy. Bexxar uses antibodies joined to radiolabeled iodine to target cancerous cells and destroy them. The antibodies attach to a protein found only in B-cells, some of which are non-Hodgkin's lymphoma B-cells, and the radiation then kills the cells. Because less non-cancerous tissue is affected by radioimmunotherapy than by chemotherapy, this form of treatment has fewer side effects. This may make radioimmunotherapy preferable to chemotherapy in some cases.
• Radioimmunotherapy - Ibritumomab Tiuxetan (Zevalin) -This drug regimen, approved by the Food and Drug Administration (FDA) in 2002, is used to treat patients with some forms of B-cell non-Hodgkin's lymphoma. It is used in conjunction with another FDA approved drug, rituximab (Rituxan), to help the immune system identify and destroy cancer cells. Because of its radioactive format and serious side effects, Zevalin is administered only to patients for whom other treatment options have failed.

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