MALT lymphoma (extranodal marginal zone B-cell lymphoma)
MALT lymphoma is a type of non-Hodgkin lymphoma (NHL).
This information 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 is more common in people over the age of 50.
Most NHL starts 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, lacrimal gland (which makes tears for the eye), 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 inflammation of the stomach lining (chronic gastritis), and over time this may lead to MALT lymphoma developing.
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 an endoscopy. This involves a flexible tube, with a tiny light and camera attached, being passed down your gullet into the stomach. During the endoscopy, samples of tissue (biopsies) will be taken from different areas of your stomach. The tissue samples will be sent to a laboratory to be examined under a microscope.
Additional tests include:
bone marrow samples.
Other tests may be used, depending on where in the body the lymphoma is.
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, how far it has spread from the lining of the stomach into the layers of the stomach is also measured.
Most MALT lymphomas are diagnosed at an early stage.
Non-Hodgkin lymphomas are divided into two groups: indolent (sometimes called low-grade) and aggressive (sometimes called high-grade). Indolent lymphomas usually grow slowly; aggressive lymphomas grow more quickly.
MALT lymphoma is usually an indolent lymphoma, but it can sometimes change (transform) to become aggressive.
Treatment for MALT lymphoma
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Treatment for MALT lymphomas is usually very successful. The treatment will depend on the type of MALT lymphoma you have and the stage it is at. 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.
MALT lymphoma of the stomach (gastric MALT lymphoma)
You will have tests to check for H. pylori infection. If this is present you’ll be given treatment called triple therapy to get rid of the infection. This involves taking a course of two antibiotics and an antacid treatment. Getting rid of H. pylori may clear all signs of the lymphoma (known as remission), although this may take several months. You’ll have regular endoscopies to check for signs of lymphoma in your stomach after your treatment.
If you don't have H. pylori, or if the lymphoma doesn't go away with triple therapy, or comes back, you may be offered one or more of the following treatments:
monoclonal antibody therapy.
There is more information about these below.
Non-gastric MALT lymphoma
MALT lymphomas that start in other areas are usually treated with chemotherapy, radiotherapy or a monoclonal antibody therapy called rituximab. Surgery may be used to remove the lymphoma, depending on where it is and how widespread it is. Sometimes people who have MALT lymphoma in the tear gland of the eye, called a lacrimal MALT, may be given antibiotic treatment.
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.
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.
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 a number of reliable sources, including:
Greer John, et al. Wintrobe’s Clinical Hematology (12th edition). 2009. Lippincott Williams and Wilkins, Philadelphia.
British Committee for Standards in Haematology, Royal College of Pathologists. Best Practice in Lymphoma Diagnosis and Reporting: Specific disease appendix. April 2012. bcshguidelines.com/documents/Lymphoma_disease_app_bcsh_042010.pdf (accessed April 2014)
Zucca E, et al Gastric marginal zone lymphoma of MALT type: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology. 2013. 24 (Supplement 6): vi144–vi148.
Zinzani P. The many faces of marginal zone lymphoma. ASH Education Book. December 8, 2012. 1: 426-432.
Thank you to Dr Nick Morley, Consultant Haematologist, and the people affected by cancer who reviewed this edition.
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