Any of several types of cancer arising in the lymphatic system
The lymphomas are a group of diseases in which immune cells become cancerous and multiply uncontrollably in a lymph node. Initially, a single node may be affected, but the cancer may spread to other nodes and also to other tissues, such as the bone marrow.
Lymphomas can be divided into two main categories: Hodgkin’s and non-Hodgkin’s lymphomas. In Hodgkin’s lymphoma, a particular type of cancer cell is present. All the other types of lymphoma are classified as non-Hodgkin’s lymphoma. Non-Hodgkin’s lymphoma is about three times more common than Hodgkin’s lymphoma, and it usually develops in people over the age of 50. Hodgkin’s lymphoma most commonly occurs in people who are between the ages of 15 and 30 and the ages of 55 and 70. Different types of lymphoma grow and spread at different rates.
The cause of lymphoma is not known but the condition sometimes runs in families, suggesting that a genetic factor is involved. Lymphomas are more common if immunity is reduced, such as in people with AIDS (see HIV infection and AIDS) or those who are taking immunosuppressant drugs. Some lymphomas may be triggered by a viral infection. For example, Burkitt’s lymphoma, which is common in children in equatorial Africa, is associated with the Epstein–Barr virus.
The symptoms of lymphoma, common to all types, may include:
One or more persistent and painless swellings in the neck, armpits, or groin caused by enlarged lymph nodes.
Fever and sweating at night.
Abdominal swelling and discomfort due to enlarged lymph nodes or an enlarged spleen.
Some people with lymphoma develop anaemia, which causes symptoms such as tiredness, pale skin, and shortness of breath on mild exertion.
Your doctor may suspect lymphoma from your symptoms and following a physical examination. He or she may arrange for a blood test to check for anaemia. A tissue sample may also be taken from a swollen node to find out whether cancerous cells are present.
If lymphoma is diagnosed, further tests may be needed to find out how far the disease has progressed. These may include imaging techniques, such as CT scanning, to assess the size of lymph nodes in the chest and abdomen. You may also have bone marrow aspiration and biopsy to determine whether your bone marrow is affected.
Treatment depends on the type of lymphoma and how far it has spread. If only one node or one group of nodes is affected, the lymphoma may be treated with local radiotherapy alone. When more than one group of lymph nodes is affected, the usual treatment is chemotherapy, which may be combined with corticosteroid drugs or radiotherapy.
The prognosis depends on the type of lymphoma and how far it has spread. If the cancer is not detectable following treatment, the disease is said to have gone into remission. However, lymphomas sometimes recur, and a second course of treatment may be necessary. If remission continues for 5 years or more, the risk of recurrence is small.
After treatment for Hodgkin’s lymphoma, at least 8 in 10 people enter a long-term period of remission and can be assumed to be cured. About half of all people treated for non-Hodgkin’s lymphoma enter long-term remission and are considered to be cured.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.