What Is Hodgkin's Disease?

Hodgkin's disease is one of a group of cancers called lymphomas. Lymphoma is a general term for cancers that develop in the lymphatic system. Hodgkin's disease, an uncommon lymphoma, accounts for less than 1 percent of all cases of cancer in this country. Other cancers of the lymphatic system are called non-Hodgkin's lymphomas.  

The lymphatic system is part of the body's immune system. It helps the body fight disease and infection. The lymphatic system includes a network of thin lymphatic vessels that branch, like blood vessels, into tissues throughout the body. Lymphatic vessels carry lymph, a colorless, watery fluid that contains infection-fighting cells called lymphocytes. Along this network of vessels are small organs called lymph nodes. Clusters of lymph nodes are found in the underarms, groin, neck, chest, and abdomen. Other parts of the lymphatic system are the spleen, thymus, tonsils, and bone marrow. Lymphatic tissue is also found in other parts of the body, including the stomach, intestines, and skin.

Cancer is a group of many related diseases that begin in cells, the body's basic unit of life. To understand Hodgkin's disease, it is helpful to know about normal cells and what happens when they become cancerous. The body is made up of many types of cells. Normally, cells grow and divide to produce more cells only when the body needs them. This orderly process helps keep the body healthy. Sometimes cells keep dividing when new cells are not needed, creating a mass of extra tissue. This mass is called a growth or tumor. Tumors can be either benign (not cancerous) or malignant (cancerous).

In Hodgkin's disease, cells in the lymphatic system become abnormal. They divide too rapidly and grow without any order or control. Because lymphatic tissue is present in many parts of the body, Hodgkin's disease can start almost anywhere. Hodgkin's disease may occur in a single lymph node, a group of lymph nodes, or, sometimes, in other parts of the lymphatic system such as the bone marrow and spleen. This type of cancer tends to spread in a fairly orderly way from one group of lymph nodes to the next group. For example, Hodgkin's disease that arises in the lymph nodes in the neck spreads first to the nodes above the collarbones, and then to the lymph nodes under the arms and within the chest. Eventually, it can spread to almost any other part of the body.
Risk Factors Associated with Hodgkin's Disease

Scientists at hospitals and medical centers all across the country are studying Hodgkin's disease. They are trying to learn more about what causes the disease and more effective methods of treatment.

At this time, the cause or causes of Hodgkin's disease are not known, and doctors can seldom explain why one person gets this disease and another does not. It is clear, however, that Hodgkin's disease is not caused by an injury, and it is not contagious; no one can "catch" this disease from another person.

By studying patterns of cancer in the population, researchers have found certain risk factors that are more common in people who get Hodgkin's disease than in those who do not. However, most people with these risk factors do not get Hodgkin's disease, and many who do get this disease have none of the known risk factors.

The following are some of the risk factors associated with this disease:

• Age/Sex -- Hodgkin's disease occurs most often in people between 15 and 34 and in people over the age of 55. It is more common in men than in women.

• Family History -- Brothers and sisters of those with Hodgkin's disease have a higher-than-average chance of developing this disease.

• Viruses -- Epstein-Barr virus is an infectious agent that may be associated with an increased chance of getting Hodgkin's disease.

People who are concerned about the chance of developing Hodgkin's disease should talk with their doctor about the disease, the symptoms to watch for, and an appropriate schedule for checkups. The doctor's advice will be based on the person's age, medical history, and other factors.