July 13, 2024
This page was reviewed under our medical and editorial policy by Alex Herrera, M.D., professor, division of lymphoma, Department of Hematology & Hematopoietic Cell Transplantation, City of Hope® Cancer Center Duarte
Lymphoma is a type of blood cancer with two main subtypes: Hodgkin lymphoma (which accounts for 0.4% of all new cancer cases) and non-Hodgkin lymphoma (which accounts for 3.8% of all cancer cases). In 2026, the American Cancer Society projects that about 79,320 people will be diagnosed with non-Hodgkin lymphoma and 8,920 will be diagnosed with Hodgkin lymphoma in the United States.
Lymphoma is a type of cancer that starts in white blood cells known as lymphocytes. This cancer affects the lymphatic system, which runs throughout the entire body and is part of the body's defense against germs. Lymphoma is the most common type of blood cancer.
Lymphoma develops when lymphocytes — infection-fighting white blood cells in the immune system — become abnormal and grow and divide uncontrollably into tumors. Lymphocytes are the central part of the immune system and circulate throughout the body responding to bacteria and viruses.
With lymphoma, abnormal white blood cells grow in number (also causing the lymph nodes to swell) not because of an infection but because of a defect inside the cells. Instead of fighting disease, these cells, which have no real purpose in the body, grow and take up space. In contrast to a normal immune response, swelling in the lymph nodes does not subside with lymphoma.
Factors that put people at higher risk for getting lymphoma are called risk factors. Doctors do not know what causes most lymphomas, and very little can be done to prevent them. For most patients, it is not one but a combination of factors that likely contributes to developing lymphoma.
Immune system problems: This includes HIV/AIDS, other autoimmune diseases and being on immune-suppressing medication.
Age: Age increases the risk of most cancers, including lymphoma.
Sex: Males are more likely than females to be diagnosed.
Race: Caucasians are more likely to develop lymphoma.
Previous cancer treatments: Chemotherapy and radiation therapy may increase the risk of lymphoma.
Infections: Infections, such as the Epstein-Barr virus, human T-cell leukemia virus type 1 and human herpes virus-8, increase the risk of certain lymphoma subtypes. Other infections, such as chlamydia, helicobacter pylori and hepatitis C, may also be associated.
Chemicals: Exposure to chemicals, pesticides and other toxins, like Agent Orange and benzene, may be linked to developing lymphoma.
Obesity: Being overweight is associated with developing several cancers and, in some studies, has shown an association with lymphoma.
Lymphoma is not passed on from parents to children, and the majority of people with family members who have the disease will not develop it. If someone has a brother, sister or parent with certain types of lymphoma, his or her risk of developing that lymphoma type increases slightly.
Maintaining a healthy weight and diet has been shown in some studies to lower the risk of developing lymphoma. Studies have linked eating a diet rich in fruits and vegetables with substantially reduced risk of lymphoma and, as with many cancers, being physically active and not overconsuming products with animal fats may also help.
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