What is Hodgkin Lymphoma?
Hodgkin lymphoma (HL) is also known as Hodgkin disease. It is a type of blood cancer that starts in the white blood cells known as lymphocytes.
Lymphocytes collect in the lymphatic system in the body, which is a part of the immune system that carries lymph fluid throughout the body. Because the lymphatic system is so widespread, HL can begin in many different places in the body. As the lymphoma cells collect, they can form tumors in the lymph system, such as in the lymph nodes or spleen.1,2
There are two main types of lymphoma: Hodgkin lymphoma and non-Hodgkin lymphoma. Hodgkin lymphoma is named for Dr. Thomas Hodgkin who first described it as a cancer of the lymph nodes in 1832.2
About 8,000 people in the U.S. were diagnosed with HL in 2019.3
What are the different types of Hodgkin lymphoma?
Most people with HL have classic Hodgkin lymphoma (cHL). Classic HL accounts for more than 9 out of 10 cases of HL. In classic HL, the cancerous cells are a specific type of cell referred to as Reed-Sternberg cells. Classic HL has 4 different subtypes:
- Nodular sclerosis Hodgkin lymphoma, which can occur at any age but is most often found in teens and young adults. It tends to develop in the neck or chest.
- Mixed cellularity Hodgkin lymphoma, which mostly occurs in older adults. It tends to develop in the upper half of the body.
- Lymphocyte-rich Hodgkin lymphoma, which usually occurs in the upper half of the body and typically only involves a few lymph nodes.
- Lymphocyte-depleted Hodgkin lymphoma, which usually occurs in older people. It is generally discovered at later stages of the disease.1
The remaining 5 perecent of HL are knowns as nodular lymphocyte predominant Hodgkin lymphoma (NLPHL). The cancer cells are referred to as "popcorn cells" because of how they look under a microscope. NLPHL usually develops in the lymph nodes in the neck and/or under the arms. It can occur in people of any age.1
What causes it?
The exact cause of HL remains unknown, but the cancer can begin with a change to the DNA of the lymphocytes. There are two main types of lymphocytes: B lymphocytes (or B cells) and T lymphocytes (or T cells). HL usually beings in B lymphocytes.1
Each time any cell in the body divides, it makes a new copy of its DNA. Sometimes errors occur during this process. These errors can cause the cell to develop abnormally. This may lead to the development of cancer through the activation of oncogenes or the suppression of tumor suppressor genes. Oncogenes are genes that control how cells grow, multiply, and stay alive. Tumor suppressor genes are normally a stop mechanism that cause damaged cells to die or slow cell growth. When tumor suppressor genes are turned off, cancer cells can multiply more easily.1
Researchers have found that several DNA mutations are present in Reed-Steinberg cells. These mutations can cause the cells to multiply and live longer than normal. The Reed-Steinberg cells also secrete cytokines, chemicals that attract other cells into the lymph nodes and add to the swelling of the nodes. The cells which are brought into the lymph node by these cytokines can provide substances that help Reed-Steinberg cells to continue to grow.1
How does it develop?
HL usually begins in the lymph nodes in the upper part of the body, including the chest, neck, and underarms. As the cancerous cells multiply, HL can spread through the lymph system going from lymph node to lymph node. If the disease continues, it can also spread through the bloodstream to other areas, including the liver, lungs, and bone marrow.1
Who gets Hodgkin lymphoma?
Both children and adults can get HL. It is most often diagnosed in young adults in their 20s or in older adults after age 55. About 10-15 percent of cases are found in children or teens. It is rare in children under the age of 5.1
What factors increase a person’s risk of developing it?
Risk factors that may potentially increase a person's chances of developing HL include:
- The Epstein-Barr virus, which is known to cause mononucleosis ("mono")
- Human immunodeficiency virus (HIV)
- Being male (there is a slightly higher incidence of HL in men than women)
- Having a family history of HL, particularly brothers or sisters (or twins)1,2
In addition, living in the U.S., Canada or Europe is associated with a higher risk than living in African or Asian countries. HL also occurs more often in people of higher socioeconomic background.1
What are the common symptoms?
The most common symptom of HL is swollen or enlarged lymph nodes. Unlike swollen lymph nodes that can occur during infections, the enlarged lymph nodes of HL are typically painless. These swollen lymph nodes are often found in the neck, underarms, or upper chest, although they can also occur in the groin or stomach area.1,2
Other symptoms of HL that are referred to as "B symptoms" include:
HL may also cause general symptoms, like:
- Itchy skin
- Fatigue or feeling tired
- Loss of appetite
- Difficulty breathing (especially if lymph nodes in the chest are affected)
- Abdominal pain or a feeling of fullness (due to the spleen being enlarged)1,2
How is it staged?
Hodgkin lymphoma may be classified as Stage I, II, III, or IV. The staging may be further classified as A, B, or E.
- A is defined as no symptoms.
- B is defined as experiencing symptoms fever, weight loss, or night sweats.
- E is defined as cancer found outside of the lymph system.1,2
What is the prognosis?
Survival rates are based on previous outcomes of people who survive a set amount of time after diagnosis. In cancer estimates, experts use the "5-year survival rate" as a marker. However, it is important to keep in mind that many people live beyond 5 years after diagnosis and the statistics do not necessarily apply to all individuals.
Based on data from 2009-2015, the National Cancer Institute has determined the 5-year survival rate for all cases of Hodgkin lymphoma is 86.6 percent. The disease is more treatable when caught in its earlier stages, and the survival rate declines if the disease is found in its later stages when it has spread to other parts of the body.1,3