- Posted by jdavis on August 24, 2011
Lymphoma is a general term for a group of cancers that originate in the lymphatic system. Lymphomas are divided into two major categories: Hodgkin lymphoma and all other lymphomas, called non-Hodgkin lymphoma (NHL). About 53 percent of the blood cancers that occur each year are lymphoma.
Lymphoma results when a lymphocyte, a type of white blood cell, undergoes a malignant change and begins to multiply, eventually crowding out healthy cells and creating tumors that enlarge the lymph nodes or other parts of the immune system.
Lymphoma generally starts in lymph nodes or collections of lymphatic tissue in organs like the stomach or intestines. It may involve the marrow and the blood in some cases. Lymphoma may spread from one site to other parts of the body. Lymphocytic leukemias originate and are most prominent in the marrow and spill over into the blood. They occasionally spread to involve the lymph nodes.
There are more than 30 subtypes of lymphoma, consisting of five types of Hodgkin lymphoma (also known as Hodgkin disease) and over 25 types of non-Hodgkin lymphoma (NHL). Lymphoma is the most common blood cancer and the third most common cancer of childhood. In the United States, NHL is the fifth most common cancer among males and females. About 74,340 Americans will be diagnosed with lymphoma in 2008.
Lymphoma Causes & Risk Factors
Most cases of Hodgkin lymphoma occur in people who do not have any identifiable risk factors and most people with presumptive risk factors do not get the disease. The causes of Hodgkin lymphoma are uncertain.
Epstein-Barr virus has been associated with nearly half of cases. However, this virus has not been conclusively established as a cause of Hodgkin lymphoma.
People infected with HTLV and HIV also have an increased probability of developing Hodgkin lymphoma.
As with many cancers, there are some cases of hereditary disease; there is an increased incidence of Hodgkin lymphoma in siblings of patients with the disease.
There is an apparent increase in NHL incidence in farming communities. Studies point to specific ingredients — such as organochlorine, organophosphate and phenoxyacid compounds — in herbicides and pesticides as being associated with lymphoma. However, the number of NHL cases caused by such exposures has not been defined.