Lymphoma is a form of cancer that affects the immune system - specifically, it is a cancer of immune cells called lymphocytes, a type of white blood cell. There are two broad types of lymphoma and many subtypes.
The two types of lymphoma are described as: Hodgkin's or non-Hodgkin's.
Lymphoma can occur at any age but is the most common cancer in young people. It is often very treatable, and most people live for a long time after being diagnosed.
Use this page for comprehensive and easy-to-follow information about lymphoma - both non-Hodgkin's and Hodgkin's lymphoma.
Contents of this article:
You will also see introductions at the end of some sections to any recent developments that have been covered by MNT's news stories. Also look out for links to information about related conditions. Note that this article is also available in Spanish.
Fast facts on lymphoma
Here are some key points about lymphoma. More detail and supporting information is in the body of this article.
- Lymphoma is cancer that develops in the lymph nodes and lymphatic system.
- The two main types of lymphoma are non-Hodgkin's (about 90% of cases) and Hodgkin's (about 10%).
- The main symptom is usually enlargement of lymph nodes that does not go away (as it does after infection).
- There are an estimated 761,659 people living with, or in remission from, lymphoma in the US.3
- For Hodgkin's lymphoma, an estimated 177,526 people are living with the disease or are in remission.
- For non-Hodgkin's lymphoma, an estimated 584,133 people are living with the disease or are in remission.
- There are around 79,990 new cases of lymphoma diagnosed in the US each year (9,190 cases of Hodgkin's lymphoma, 70,800 cases of non-Hodgkin's lymphoma).
- Lymphoma cannot be prevented, but survival rates after treatment are good.
What is lymphoma?
Lymphoma is cancer of the lymph system (or lymphatic system), which is part of our immunity. It is characterized by the formation of solid tumors in the immune system.1 The cancer affects immune cells called lymphocytes, which are white blood cells.
The lymphatic system is a system of vessels that branch back from virtually all our tissues to drain excess fluids and present foreign material to the lymph nodes. Learn more about the lymphatic system here.
Statistics from the US National Cancer Institute estimate that there are nearly 20 cases of non-Hodgkin's lymphoma for every 100,000 people in the American population.2
Hodgkin's lymphoma, meanwhile, is relatively rare, with around three cases in every 100,000 people.3
About 90% of lymphomas are the non-Hodgkin's type while about 10% are Hodgkin's.1
Cancer is a group of over 100 diseases, all of which start with the growth of abnormal cells. Instead of dying in the normal cell life cycle, cancerous cells continue to divide into new abnormal cells, and grow out of control.4
Lymphatic cancers are classified by the type of immune cells affected.
In non-Hodgkin's lymphoma, B-cells and T-cells are affected - both being types of lymphocyte white blood cell with special roles in immunity. In the US, B-cell lymphomas are much more common than T-cell ones.5
In Hodgkin's lymphoma, the cancer cells are usually an abnormal type of B lymphocyte, named Reed-Sternberg cells. There are many subtypes of Hodgkin's lymphoma, typed by differences seen under the microscope - but a very high percentage of cases are classed as "classic" Hodgkin's.6
The short YouTube video below, produced by the American Society of Hematology, shows how lymphoma develops.
Types of lymphoma
There are many different types of lymphoma depending on the type of lymphatic cells affected.
Hodgkin's lymphoma can occur at any age, affects more men that women and the majority will be completely cured.
Hodgkin's lymphoma is diagnosed when a special type of cell, the Reed-Sternberg cell, is seen under the microscope.5
Non-Hodgkin's lymphoma accounts for all the other types of lymphoma. These can be high grade or low grade and the treatment and prognosis varies.6
What causes lymphoma?
For most cancers, researchers are still trying to understand how they are caused. The same is true for lymphoma - doctors do not know what causes it, although it is more likely to occur in certain people.5,7,8
Medical researchers have identified certain risk factors that make lymphoma more likely, although they often do not understand why:5,8
- Age - most non-Hodgkin lymphomas are in people 60 years of age and over
- Sex - there are different rates of different types of non-Hodgkin's lymphoma across the sexes
- Ethnicity and location - in the US, African-Americans and Asian-Americans are less prone than white Americans, and the disease is more common in developed nations of the world
- Chemicals and radiation - some chemicals used in agriculture have been linked, as has nuclear radiation exposure
- Immune deficiency - for example, caused by HIV infection or in organ transplantation
- Autoimmune disease, in which the immune system attacks the body's own cells
- Infection - certain viral and bacterial infections increase the risk. The Helicobacter Infection has been implicated, as has the Epstein Barr Virus (the virus that causes glandular fever)13
- See the American Cancer Society's page for more detail on risk factors for non-Hodgkin's lymphoma.
- Infectious mononucleosis - infection with Epstein-Barr virus
- Age - two specific groups are most affected: typically people in their 20s, and people over the age of 55 years
- Sex - slightly more common in men
- Location - most common in the US, Canada and northern Europe; least common in Asia
- Family - if a sibling has the condition, the risk is slightly higher, and very high if there is an identical twin
- Affluence - people from higher socioeconomic status are at greater risk
- HIV infection
- See the American Cancer Society's page for more detail on risk factors for Hodgkin's lymphoma.
Recent developments on the causes of lymphoma
Using DNA samples from research unrelated to cancer, two teams of scientists have uncovered early, pre-cancerous genetic changes in the blood that are linked to increased chances of developing blood cancers such as leukemia, lymphoma or myelodysplastic syndrome.
Research published in the Annals of Internal Medicine found that certain patients with celiac disease were at higher risk of lymphoma.
Research published in The Journal of Cancer Research found links in a study of mice between certain make-ups of gut bacteria and lymphoma survival rates, opening up the possibility of preventive measures.
On the next page we look at the signs and symptoms of lymphoma and the available tests to diagnose it. On the final page we take a look at the available treatments for lymphoma.