MALT lymphoma (extranodal marginal zone B-cell lymphoma)
This information is about a type of non-Hodgkin lymphoma (NHL) called MALT lymphoma.
This section should ideally be read with our general information about NHL. We hope this information answers your questions. If you have any further questions, you can ask your doctor or nurse at the hospital where you are having treatment.
Non-Hodgkin lymphoma (NHL) is a cancer of the lymphatic system. The lymphatic system is made up of organs such as the bone marrow, thymus, spleen, and the lymph nodes (or lymph glands). Lymph nodes are connected by a network of tiny lymphatic vessels that contain lymph fluid. There is also lymphatic tissue in other organs, such as the skin, lungs and stomach.
There are lymph nodes all over the body. As lymph fluid flows through the lymph nodes, the nodes collect and filter out anything harmful or that the body doesn't need. This includes bacteria, viruses, damaged cells and cancer cells.
Lymph fluid contains cells called lymphocytes. These are a type of white blood cell that help the body fight infection and disease. Lymphocytes start to grow in the bone marrow, where blood cells are made. The two main types of lymphocytes are B-cells and T-cells. B-cells mature in the bone marrow, while T-cells mature in the thymus gland behind the breast bone. When they're mature, both B-cells and T-cells help fight infections.
Lymphoma is a disease where either T-cells or B-cells grow in an uncontrolled way.
There are many different types of NHL. The types are grouped (or classified) according to certain characteristics, such as the type of cell involved (B-cell or T- cell). The most widely used classification system is produced by the World Health Organisation.
MALT lymphoma is a cancer of the B-cell lymphocytes. It usually affects older people who are in their 60s.
Most NHLs start in the lymph nodes, but MALT lymphoma starts in a type of lymphatic tissue called mucosa-associated lymphoid tissue (MALT). Mucosa is the name for the tissue that lines some of the organs in the body.
The stomach is the most common area for MALT lymphoma to develop, but it may start in other organs, such as the lung, thyroid gland, salivary gland or bowel.
Because MALT lymphoma develops outside the lymph nodes, it's also known as extranodal lymphoma.
Causes of MALT lymphoma
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MALT lymphomas usually start in areas of the body where there's been long-term inflammation, due to an infection or an autoimmune condition affecting that area. An autoimmune condition causes the body's immune system to attack body tissue rather than protect it.
Most cases of MALT lymphoma affecting the stomach are linked to infection by a type of bacteria called Helicobacter pylori (H. pylori). Untreated H. pylori infection can cause ongoing inflammation of the stomach lining (chronic gastritis), and in turn this may lead to MALT lymphoma developing.
MALT lymphoma of the thyroid gland usually occurs in people with an autoimmune condition called Hashimoto’s thyroiditis.
MALT lymphoma of the salivary glands is more common in people with an autoimmune condition called Sjögren’s syndrome.
The causes of MALT lymphoma in other parts of the body are unknown.
MALT lymphoma is not infectious and cannot be passed on to other people.
Signs and symptoms of MALT lymphoma
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The symptoms depend on where in the body the lymphoma started.
MALT lymphoma in the stomach may cause symptoms such as indigestion, loss of appetite, tiredness (fatigue) and weight loss.
How MALT lymphoma is diagnosed
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If you have digestive symptoms such as feeling sick, or pain in the area of your stomach, your doctor will arrange for you to have a flexible tube, with a tiny light and camera attached, passed down your gullet and into the stomach (endoscopy). During the endoscopy a small sample of cells is taken from the stomach (called a biopsy). The cells are then examined under a microscope.
Additional tests include:
bone marrow samples.
The results of these tests are used to find out more about the lymphoma and how far it has spread in the body. This information is used to help decide which treatment is most appropriate. You can read more about these tests in our information on tests for NHL.
Staging and grading of MALT lymphoma
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The stage of MALT lymphoma describes whether it is affecting only one area of the body or has spread to nearby or distant lymph nodes, or to other parts of the body.
In MALT lymphoma of the stomach, the extent of its spread from the lining of the stomach into the layers of the stomach is also measured.
For practical purposes, non-Hodgkin lymphomas are divided into two groups: indolent (sometimes called low-grade) and aggressive (sometimes called high-grade). Indolent lymphomas are usually slow‑growing, and aggressive lymphomas grow more quickly.
MALT lymphoma is usually an indolent lymphoma, but it can sometimes change (transform) to become more aggressive.
Treatment for MALT lymphoma
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Most MALT lymphomas are diagnosed at an early stage and treatment, even if the lymphoma has spread, is usually very successful. The treatment will depend on the type of MALT lymphoma you have and the stage it is at:
MALT lymphoma of the stomach (gastric MALT lymphoma)
If tests show that H. pylori is present in the tumour tissue, you’ll be given a course of antibiotic and antacid treatment called triple therapy. This treatment often gets rid of all signs of the lymphoma (known as remission), but it may take several months or more for the full benefit to be seen. You'll be followed up closely after this with regular endoscopies and biopsies, usually for the next two years.
If you don't have H. pylori, or if after antibiotic and antacid therapy the lymphoma doesn't go away, or comes back, you may be treated with low doses of radiotherapy to the stomach, or with chemotherapy.
Sometimes a monoclonal antibody drug called rituximab (Mabthera®) is used. This may be given with chemotherapy or on its own. Occasionally an operation to remove the stomach may be done.
Non-gastric MALT lymphoma
MALT lymphomas that start in other areas are treated in a similar way with chemotherapy, rituximab and radiotherapy. Surgery may be used to remove the lymphoma, depending on where it is and how widespread it is.
If the lymphoma is growing very slowly and not causing any problems, you may not need any treatment for some time. Your doctor will monitor you closely so that if the lymphoma does start to grow, your treatment will be started.
Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. Chemotherapy for MALT lymphoma can usually be given as a tablet. Chlorambucil tablets are a commonly used type of chemotherapy. Other drugs that may also be used include cyclophosphamide, fludaribine and cladribine.
Monoclonal antibody therapy
Monoclonal antibodies are drugs that recognise, target and stick to specific proteins on the surface of cancer cells, and can stimulate the body’s immune system to destroy these cells. Rituximab is a monoclonal antibody that is given as a drip into a vein. It can be given with chemotherapy or sometimes on its own to treat MALT lymphoma.
Radiotherapy uses high-energy rays to destroy cancer cells, while doing as little harm as possible to normal cells. Radiotherapy is an effective treatment for MALT lymphoma of the stomach that hasn't spread to lymph nodes. It can also be used to treat early MALT lymphoma in some other parts of the body.
Occasionally, early MALT lymphomas that haven't spread may be removed with surgery. For MALT lymphomas of the stomach, radiotherapy or chemotherapy are often used to avoid having the stomach removed with surgery.
Steroids are drugs that are often given with chemotherapy to help treat lymphomas. They also help you feel better and can reduce feelings of sickness (nausea).
Clinical trials for MALT lymphoma
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New treatments for MALT lymphoma are being researched all the time. Your doctor may invite you to take part in a clinical trial to compare a new treatment against the best available standard treatment. They must discuss the treatment with you and have your informed consent before entering you into a trial.
Before any trial is allowed to take place, it must be approved by a research ethics committee, which protects the interests of those taking part.
You may decide not to take part, or to withdraw from the trial at any stage. You will then receive the best standard treatment available.
Follow-up for MALT lymphoma
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When treatment is over you will have regular check-ups at the hospital.
After triple therapy for MALT lymphomas of the stomach, you will have regular endoscopies and biopsies. These will be done 2-3 months after treatment and then at least twice a year for up to two years.
Other tests may be used for people whose MALT lymphoma affects other areas. You can read more about this in our general information about NHL.
Information and support
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Everyone has their own way of dealing with their illness and the different emotions they experience. You may find it helpful to talk things over with family and friends or your doctor or nurse. You can also contact our cancer support specialists or the organisations below for more information and support.
Other useful organisations
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is a national group promoting the welfare of people with leukaemia and related blood disorders, including NHL. It has regional support groups in many counties.
The Lymphoma Association
The Lymphoma Association gives emotional support, advice and information on all aspects of NHL. It has a national network of people with lymphoma and local groups.
This information has been compiled using information from a number of reliable sources, including:
Facilities for the treatment of adults with haematological malignancies. Levels of Care. British Committee for Standards in Haematology. 2010.
Lee, et al. Wintrobe’s Clinical Haematology. 12th edition. 2009. Lippincott Williams and Wilkins.
Parker A, et al. Best Practice in Lymphoma Diagnosis and Reporting, Specific disease appendix. BSCH guidelines. 2010.
Zucca E and Dreyling M. Gastric marginal zone lymphoma of MALT type: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology 21 (Supplement 5): v175–v176, 2010.
Thank you to Professor Rajnish Gupta, Consultant Medical Oncologist, and the people affected by cancer who reviewed this edition. Reviewing information is just one of the ways you could help when you join our Cancer Voices network.