Non-Hodgkin lymphoma (NHL) is a cancer of the lymphatic system.
There are many types of NHL. Some grow very slowly and may not need treatment for months or years. In some cases they may never need treatment. Other types grow quickly and need treatment soon after diagnosis.
How does non-Hodgkin lymphoma develop?
- NHL, like other types of cancer, is a disease of the body’s cells.
- The body is made up of cells that need to be replaced as they age or are damaged. This happens by cell division, which is when a cell divides and makes a new copy of itself.
- Normally, cell division is carefully controlled so the right amount of cells is made to meet the needs of the body. However, if this process gets out of control for some reason, too many cells are made and a cancer can develop.
- In NHL, blood cells called lymphocytes become abnormal. These abnormal lymphocytes (lymphoma cells) keep dividing and grow out of the body’s control. Over time, the number of lymphoma cells increases and they form a lump called a tumor.
- The most common place for this to happen is in the lymph nodes. But, NHL can begin in almost any part of the body including; the stomach, small bowel, skin, tonsils, thyroid or testicles. Lymphoma that grows outside the lymph nodes is called extranodal lymphoma.
- Because lymphocytes travel around the body, NHL can spread from where it first started. It can spread through the lymphatic system from lymph nodes in one part of the body to lymph nodes elsewhere. Lymphoma cells can also travel in the bloodstream to organs such as the bone marrow, liver or lungs. When the lymphoma cells reach a new area, they may carry on dividing and form a new tumor.
There are many different types of NHL. It’s important your doctors know which type you have so that they can give you the best treatment.
Lymphomas are often described as B-cell lymphomas or T-cell lymphomas according to whether they began in B-cell lymphocytes or T-cell lymphocytes.
Type of B-cell lymphomas
B-cell lymphomas are more common than T-cell lymphomas. About 9 out of 10 people diagnosed with NHL have a B-cell lymphoma.
The most common types of B-cell lymphomas are:
- diffuse large B-cell lymphoma (DLBCL)
- follicular lymphoma (FL)
Other less common types include:
- extranodal marginal zone B-cell – MALT
- mantle cell lymphoma
- Burkitt lymphoma
- mediastinal large B-cell lymphoma
- nodal marginal zone B-cell lymphoma
- small lymphocytic lymphoma
- lymphaplasmacytic lymphoma(also called Waldenstrom’s macroglobulinaemia)
Types of T-cell lymphomas
T-cell lymphomas are much less common. There are a number of different types, including:
- peripheral T-cell lymphoma
- skin (cutaneous) lymphomas, including Mycosis fungoides and Sézary syndrome
- anaplastic large cell lymphoma
- T-cell lymphoblastic lymphoma
Indolent and aggressive lymphomas
Lymphomas are also often grouped as either indolent or aggressive.
Indolent lymphomas (sometimes called low-grade)
These grow very slowly and may need little or no treatment for months or possibly years. Some people will never need treatment. Follicular lymphoma (FL) is the most common type of indolent NHL.
Aggressive lymphomas (sometimes called high-grade)
These grow more quickly. They usually cause symptoms and need immediate treatment. Diffuse large B-cell lymphoma (DLBCL) is the most common type of aggressive lymphoma.
One type of lymphoma, called mantle cell lymphoma, sits between indolent and aggressive lymphoma and is often treated as an aggressive lymphoma.
Central nervous system (CNS) lymphoma
A lymphoma is a malignant tumor of the lymphatic system. The lymphatic system helps defend us against infection and disease. Lymphomas that start in the brain are called primary CNS lymphomas and are rare. People who have a weak immune system are more at risk of getting this type of tumor