This information is about a specific type of non-Hodgkin lymphoma (NHL), known as MALT lymphoma. It should ideally be read with our general information about non-Hodgkin lymphoma.
MALT lymphoma (or MALToma) is a relatively rare form of non-Hodgkin lymphoma. Most NHL develops in the lymph nodes (nodal lymphoma). MALT lymphoma starts in Mucosa-Associated Lymphoid Tissue, which is lymphatic tissue that is found in other parts of the body such as the stomach, thyroid gland, lungs or the eyes, and is therefore known as extranodal lymphoma.
MALT lymphoma is a cancer of the B-cell lymphocytes. It belongs to the group of marginal zone B-cell lymphomas. Marginal zone lymphoma can be either 'nodal' or 'extranodal'. MALT lymphoma is an extranodal marginal zone B-cell lymphoma. We also produce information about nodal marginal zone B-cell lymphoma.
MALT lymphoma accounts for about one in 20 of all cases of lymphoma. It can occur at any age from early adulthood to old age, but is more common in people over 60. It is slightly more common in women than in men.
Causes of MALT
Many MALT lymphomas affecting the stomach are caused by a type of bacteria called Helicobacter pylori (see Treatment section). The causes of MALT lymphoma in other parts of the body are unknown. MALT lymphoma, like other cancers, is not infectious and cannot be passed on to other people.
Signs and symptoms
The stomach is the most common site for MALT lymphoma, but it may also occur in the lung, the thyroid, salivary gland and other organs such as the intestine.
The symptoms caused by the cancer will vary depending on which organ is affected. When MALT lymphoma develops in the stomach, it may cause symptoms such as indigestion, bleeding into the stomach, and weight loss. Some people experience a loss of appetite and tiredness.
How it is diagnosed
If you have digestive symptoms such as feeling sick, or pain in the area of your stomach, the doctor will arrange for you to have a flexible tube passed down your gullet and into the stomach (endoscopy). Photographs can then be taken of the stomach, and a small sample of cells is taken for examination under a microscope (biopsy).
Additional tests, including blood tests, x-rays, scans and bone marrow samples, are then used to get more information about the type of lymphoma, and how far it has spread in the body. This information is used to help decide which treatment is most appropriate for you.
Staging and grading
The stage of MALT lymphoma describes whether the lymphoma is affecting only one area of the body – for example, the stomach – or whether it has spread to anywhere else in the body.
It is rare for MALT lymphoma to spread to the lymph nodes, but it can. If it does, the stage refers to how many groups of lymph nodes are affected, where they are in the body, and whether other organs are affected.
For practical purposes, non-Hodgkin lymphomas are also divided into two groups: low- and high-grade. Low-grade lymphomas are usually slow-growing, and high-grade lymphomas tend to grow more quickly.
MALT lymphoma is usually low-grade and slow-growing. However, it can sometimes change (transform) to a high-grade.
Most cases of MALT lymphoma affecting the stomach (approximately 2 out of 3) are caused through infection by a type of bacteria called Helicobacter pylori (often abbreviated to H. pylori). When tests show that the bacteria is present in the tumour tissue, a course of intensive antibiotic treatment and anti-acid treatment, often called triple therapy, will sometimes lead to a remission of the lymphoma. Remission means that the lymphoma disappears and cannot be detected by any of the currently used tests.
For people with MALT lymphomas of the stomach, if antibiotics do not clear the condition, or the disease spreads, other treatments are given. In some circumstances, this may be radiotherapy or surgery. Sometimes chemotherapy may be given as well as radiotherapy or surgery.
When the MALT lymphoma has started in a part of the body other than the stomach, the following treatments may be considered.
Active surveillance (or active monitoring)
Some MALT lymphomas grow very slowly and may not cause any problems for many years. In this situation you may not need to have any treatment for some time, but your doctor will monitor you closely so that if the lymphoma does start to grow you can be given treatment at that time.
Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. When MALT lymphoma affects the lung or the bowel, chemotherapy is usually given. This is often a relatively simple treatment, and sometimes just involves you taking tablets called chlorambucil.
Occasionally, MALT lymphoma can change (transform) to high-grade lymphoma that needs more intensive chemotherapy. Chemotherapy can still get rid of the lymphoma for many people.
Radiotherapy is the use of high-energy rays to destroy cancer cells, while doing as little harm as possible to the healthy cells. Radiotherapy may be given to the affected part of the body. It may also be given with chemotherapy.
The lymphoma may be removed during a surgical operation. If the lymphoma is affecting the stomach, the whole stomach may need to be removed (total gastrectomy). This usually involves having all of the stomach removed, along with the lower part of the gullet. The gullet is then joined directly to the small intestine.
New treatments for MALT lymphoma are being researched all the time, and you might be invited by your doctor to take part in a clinical trial to compare a new treatment against the best available standard treatment. Your doctor must discuss the treatment with you, and have your informed consent before entering you into any clinical trial.
When treatment has ended, you will have regular check-ups at the hospital. For lymphomas affecting the stomach this will involve regular endoscopies and biopsies of the stomach to look for signs of the cancer coming back (a recurrence). Other tests may be used for people whose MALT lymphoma affects areas apart from the stomach.
The need for practical and emotional support will of course be individual. For some people with MALT lymphoma, life may seem largely unaffected; for others the diagnosis of cancer may be a cause of great fear and distress. If you would like to discuss the condition, its treatment, or the practical and emotional problems of living with MALT lymphoma, please contact our cancer support service.
Content last reviewed: 01 April 2008 Page last modified: 04 July 2008
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