MALT lymphoma

MALT lymphoma is a slow-growing type of non-Hodgkin lymphoma (NHL). Like all lymphomas, it’s a cancer of the lymphatic system, which is part of the body’s immune system.

MALT lymphoma develops when white blood cells called B-lymphocytes become abnormal and begin to grow in an uncontrolled way.

MALT lymphoma affects lymphatic tissue called mucosa-associated lymphoid tissue (MALT). Mucosa is the name for the tissue that lines some organs in the body.

The most common place for MALT lymphoma to develop is the stomach, but it can also start in other places, including the:

  • lung
  • thyroid gland
  • salivary gland
  • lacrimal gland (which makes tears for the eye)
  • bowel.

MALT lymphomas may start where there has been long-term inflammation, caused by infection or an autoimmune condition.

The symptoms depend on where in the body the lymphoma started. To diagnose MALT lymphoma, a doctor removes a sample of cells (biopsy) from the affected area. They check them for abnormal cells. They will also arrange tests and scans to find out whether the lymphoma has spread. This is called staging.

MALT lymphoma may be treated with antibiotics, chemotherapy, radiotherapy or surgery.

MALT lymphoma (extranodal marginal zone B-cell lymphoma)

MALT lymphoma is a type of non-Hodgkin lymphoma (NHL). It is more common in people over the age of 50.

This information should be read with our general information about NHL. If you have any further questions, you can ask your doctor or nurse at the hospital where you are having treatment.


Non-Hodgkin lymphoma

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 lymph nodes (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.

The lymphatic system
The lymphatic system

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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 lymphocyte are B-cells and T-cells. B-cells mature in the bone marrow, and 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 different types of lymphoma. They are grouped depending on the whether B-cells or T-cells are involved. MALT lymphoma is a cancer of the B-cell lymphocytes.


Extranodal lymphoma

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. Because MALT lymphoma develops outside the lymph nodes, it’s also known as extranodal lymphoma.

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)
  • bowel.


Causes of MALT lymphoma

MALT lymphomas usually start in areas of the body where there’s been long-term inflammation, due to an infection or 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 in the stomach are linked to infection by a type of bacteria called Helicobacter pylori (H pylori). If H pylori infection isn’t treated, it can cause inflammation of the stomach lining (chronic gastritis). 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

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)
  • weight loss.


How MALT lymphoma is diagnosed

If you have digestive symptoms such as feeling sick (nausea) or pain in your stomach, your doctor will arrange for you to have an endoscopy. This is where a flexible tube, with a tiny light and camera attached, is 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.

Endoscopy
Endoscopy

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Additional tests for MALT lymphoma include:

  • blood tests
  • x-rays and scans
  • 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 for you. You can read more about these tests in our information on tests for NHL.


Staging and grading of MALT lymphoma

Staging

The stage of MALT lymphoma describes whether it:

  • is in only one area of the body
  • 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.

Grading

Non-Hodgkin lymphomas are divided into two groups:

  • Indolent (low-grade) lymphomas usually grow slowly.
  • Aggressive (high-grade) lymphomas grow more quickly.

MALT lymphoma is usually an indolent lymphoma, but rarely, it can change (transform) to become aggressive.


Treatment for MALT lymphoma

Treatment for MALT lymphoma is usually very successful. The treatment you have 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, they can start your treatment.

Treating MALT lymphoma of the stomach (gastric MALT lymphoma)

You will have tests to check for an infection caused by a bacteria called H pylori. If you have this, you will have a 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), but this may take several months. After your treatment, you will have regular endoscopies to check for signs of lymphoma in your stomach.

If you don’t have H pylori, or if the lymphoma doesn’t go away with triple therapy, or if it comes back, you may be offered one or more of the following treatments:

There is more information about these below.

Treating non-gastric MALT lymphoma

MALT lymphomas that start in other areas are usually treated with chemotherapy, radiotherapy or a targeted 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 (lacrimal MALT) may be given antibiotic treatment.

Chemotherapy

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:

Drugs may be given on their own, with other chemotherapy drugs or with a targeted therapy drug called rituximab.

Targeted therapy

You might have a type of targeted therapy called a monoclonal antibody. Monoclonal antibodies such as rituximab (Mabthera®) target certain proteins on the surface of cancer cells.

Rituximab is given as a drip into a vein. It can be given with chemotherapy or sometimes on its own to treat MALT lymphoma.

Radiotherapy

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 has not spread to lymph nodes. It can also be used to treat early MALT lymphoma in some other parts of the body.

Surgery

Occasionally, early MALT lymphomas that have not spread may be removed with surgery.


Clinical trials for MALT lymphoma

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. Before you enter a trial, your doctor must discuss the treatment with you and get your consent (permission).

Before any trial is allowed to take place, it must be approved by a research ethics committee, which protects the interests of the people 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

When treatment is over you will have regular check-ups at the hospital.


Your feelings

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:

  • The Lymphoma Association gives emotional support, advice and information on all aspects of Hodgkin lymphoma and non-Hodgkin lymphoma. It has a national network of people with lymphoma and local groups.
  • Leukaemia CARE is a national group promoting the welfare of people with leukaemia and other blood disorders, including non-Hodgkin lymphoma. It has regional support groups in many counties.