Understanding Non-Hodgkin's Lymphoma - the Basics

What Is Non-Hodgkin's Lymphoma?

Lymphoma refers to a cancer of the lymphatic system. The lymphatic system is a network of nodes (knots of tissue) connected by vessels. Together, they drain fluid and waste products from all the organs and structures of your body. The lymph nodes act as tiny filters, straining out invading organisms and cancerous cells.

A fluid called lymph protects the body against infection. The system's main organ is the spleen, connected by a network of tiny lymphatic vessels to clusters of lymph nodes throughout the body. Lymphocytes, a type of white blood cell that attacks infectious invaders, such as bacteria, viruses, and fungi, destroy most infections before they can enter the bloodstream. When the lymphatic system is fighting an active infection, you may notice that some of your lymph nodes and tissue in the area of the infection become swollen and tender. This is normal.

Lymphoma occurs when the lymph-node cells or the lymphocytes begin to multiply uncontrollably, producing cancerous cells that have the abnormal capacity to invade other tissues throughout your body. The two main types of lymphoma are Hodgkin's disease and non-Hodgkin's lymphoma, which are classified by certain unique characteristics of the cancer cells.

Non-Hodgkin's lymphoma can be further classified into a variety of types based on other cell characteristics, such as size, arrangement, growth patterns and invasiveness. These characteristics also help your doctor predict the chance that your disease can be cured or put into remission.

Non-Hodgkin's lymphoma is much more common than Hodgkin's disease and is ranked as the fifth most common cause of cancer-related deaths. Your risk of developing non-Hodgkin's lymphoma increases as you get older. You are more likely to get this disease if you are male or white.

What Causes It?

No one knows exactly what causes non-Hodgkin's lymphoma. For most patients, the cause is never identified. Medical conditions that have been linked with an increased risk include:

• A variety of immune deficiencies present at birth.
• Down syndrome
• Klinefelter's syndrome (a genetic condition in men caused by an extra X chromosome)
• Sjögren's syndrome (an immune disorder characterized by unusual dryness of mucus membranes)
• Celiac disease (which involves trouble processing certain components of gluten, a protein in grains)
• Rheumatoid arthritis
• Systemic lupus erythematosus
• HIV infection
• Exposure to Epstein-Barr virus or human T-cell leukemia/lymphoma virus (HTLV-1).
• Ataxia-telangiectasia syndrome (a genetic disease related to trouble processing certain antibodies)
• Stomach ulcers due to infection with the bacteria Helicobacter pylori.

Other risk factors include:

• Regular exposure to certain chemicals, including arsenic, lead, vinyl chloride, asbestos, insect and weed killers, and a number of chemicals used in industries such as farming, welding and lumber.
• Exposure to nuclear accidents or explosions.
• Organ transplantation and treatment with immunosuppressant drugs to prevent organ rejection.
• Chemotherapy or radiation treatment for a previous cancer.
• A seizure disorder and treatment with a medication called Dilantin (phenytoin).