Non-Hodgkin lymphoma (NHL) is a group of cancers of the white blood cells called lymphocytes. Lymphocytes protect the body from infection and disease. Three different kinds of lymphocytes – B cells, T cells, and NK cells – can be cancerous. Most NHLs are B-cell lymphomas. These types of cancers are all called non-Hodgkin lymphoma to tell them apart from another cancer called Hodgkin lymphoma.
There are more than 30 different types of NHL that begin in the lymphocytes and spread throughout the body. NHL begins when a lymphocyte changes into a cancer cell that divides and grows into more and more cancer cells. These cancer cells join together and form tumors (lymphomas) in the lymph nodes and elsewhere in the body. The cancerous lymphocytes cause the lymph nodes in your body to enlarge, usually around the neck, under the armpits and in the groin. The cancerous lymphocytes may also collect in different parts of the body, including the liver, spleen and bone marrow.
Every year, about 69,000 people are diagnosed with NHL in the United States. Although NHL can occur in people of any age, most people diagnosed with the disease are older than 60. The chances of getting NHL increases with age. For most people, the cause of NHL is unknown.
Types of NHL
There are many different types of NHL. These lymphomas are grouped based on how quickly they grow and on the kinds of lymphocytes affected.
Lymphomas that tend to grow slowly are called indolent lymphomas. Aggressive lymphomas are ones that grow quickly. They may become life-threatening within months without treatment. Sometimes, a slow growing (indolent) lymphoma can change into a more aggressive type.
The most common types of NHL are:
- Follicular lymphoma – an indolent B-cell lymphoma
- Diffuse large B-cell lymphoma – an aggressive B-cell lymphoma
- Mantle cell lymphoma – an aggressive B-cell lymphoma
Stages of NHL
There are four stages of NHL. These stages are based on where the diseased cells are found in the body. They’re also based on how many areas of the body are affected. Lymphoma cells tend to form tumors with lymph nodes, where normal lymphocytes reside. Unlike many other cancers, even widespread (Stage 4) lymphoma is curable for many patients, though more aggressive treatment may be required. The four stages of NHL are:
Stage 1: the diseased cells are in a single lymph node group (such as in the neck or underarm)
Stage 2: the diseased cells are in more than one lymph node group but still within the upper half of the body or the lower half of the body
Stage 3: the diseased cells are in lymph nodes in both the upper and lower halves of the body
Stage 4: the diseased cells have spread to organs outside of the lymph nodes such as the liver, lungs, and bone marrow
Recurrent: the disease returns after treatment
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