MALT lymphoma

MALT lymphoma is a slow-growing type of non-Hodgkin lymphoma (NHL). Like all lymphomas, it is 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
  • skin
  • thyroid gland
  • salivary gland
  • bowel
  • eye.

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. 

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

What is MALT lymphoma (extranodal marginal zone B-cell lymphoma)?

It is best to read this information with our general information about non-Hodgkin lymphoma (NHL). If you have any more questions, you can ask your doctor or nurse at the hospital where you are having treatment.

MALT lymphoma is a slow-growing type of NHL. Like all lymphomas, it is a cancer of the lymphatic system, which is part of the body’s immune system. It 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 area for MALT lymphoma to develop is the stomach. But it may start in other parts of the body, including the:

  • lung
  • skin
  • thyroid gland
  • salivary gland
  • bowel
  • eye.


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.

Infection

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.

Other types of bacterial infection have been linked to MALT lymphoma in the skin, eye and bowel.

Long-term infection with the virus hepatitis C is also a risk factor for MALT lymphoma.

MALT lymphoma is not infectious and cannot be passed on to other people.

Autoimmune conditions

Autoimmune conditions such Hashimoto’s thyroiditis and Sjögren’s syndrome have been linked to MALT lymphoma in the thyroid gland, salivary glands and lungs.

In Hashimoto’s thyroiditis, the immune system attacks the thyroid gland. This makes it underactive.

In Sjögren’s syndrome, the immune system attacks glands that make fluid. This causes dry eyes and a dry mouth.


Signs and symptoms of MALT lymphoma

The symptoms depend on where in the body the lymphoma started.

For example, MALT lymphoma in the stomach may cause symptoms such as:

  • indigestion
  • loss of appetite
  • feeling sick (nausea)
  • weight loss.

B symptoms

Some people also have:

  • drenching night sweats
  • high temperatures (fevers) with no obvious cause
  • unexplained weight loss.

These are called B symptoms.


How MALT lymphoma is diagnosed

MALT lymphoma is diagnosed by doctors taking tissue samples biopsies from the affected area. The biopsies are sent to a laboratory for testing and to be examined under a microscope.

If you might have MALT lymphoma in the stomach, your doctor will do an endoscopy. This is where they pass a flexible tube, with a tiny light and camera attached, down the gullet into the stomach. During the endoscopy, they take biopsies from different areas of the stomach.

Other tests may include:

  • blood tests
  • x-rays and scans
  • bone marrow samples.

Doctors use the information from all these tests to find out more about the lymphoma, such as its stage and grade.


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, doctors also measure how far the lymphoma has spread from the lining of the stomach into deeper layers of the stomach.

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 a low-grade lymphoma, but rarely it can change (transform) to become a high-grade lymphoma.


Treating MALT lymphoma

Treatment for MALT lymphoma is usually very successful. The treatment you have depends 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.

Antibiotics

If you have MALT lymphoma in the stomach, you will have tests to check for an infection caused by the 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 2 antibiotics and a treatment to reduce the amount of acid made by the stomach.

Getting rid of H. pylori may clear all signs of the lymphoma (called remission). But this may take several months. After triple therapy, you will have regular endoscopies to check for lymphoma in the stomach. This is to check the lymphoma is shrinking and that you don’t need further treatment.

People who have MALT lymphoma of the eye (orbital MALT) may also be treated with antibiotics. This may make the lymphoma shrink or disappear. It can take several months for this to happen.

Radiotherapy

Radiotherapy is an effective treatment for MALT lymphomas. It can be used to treat localised MALT lymphoma.

You may be offered radiotherapy if you have localised MALT lymphoma in the stomach that:

  • is not caused by H. pylori
  • has not got better with antibiotic treatment.

Radiotherapy may also be used to treat localised MALT lymphoma in other parts of the body.

Chemotherapy

Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. It is often given together with a monoclonal antibody called rituximab

Chemotherapy may be given to treat MALT lymphoma that:

  • has spread to lymph nodes or other parts of the body
  • is not suitable for radiotherapy or antibiotic treatment
  • has come back after treatment.

Chemotherapy for MALT lymphoma may be given as tablets or into a vein. It is usually given as an outpatient. 

Commonly used chemotherapy treatments include:

These chemotherapy treatments are usually given with rituximab. When this happens, R is added to the name, for example R-CVP or R-bendamustine.

Targeted therapy

The drug Rituximab is often used with chemotherapy to treat this type of lymphoma. It works by targeting proteins on the surface of B-cell lymphocytes. This makes the body destroy these cells.

Rituximab is given as a drip into a vein or an injection under the skin.

Surgery

Occasionally, early-stage MALT lymphomas outside of the stomach are removed with surgery. This may be done during a test to diagnose the lymphoma or if other treatments are not suitable.

Clinical trials

Your lymphoma doctor may talk to you about having treatment as part of a clinical trial. Clinical trials test new treatments or new ways of giving treatments.


Follow-up after treatment

After treatment, you will have regular check-ups. These appointments are a good opportunity for you to talk to your doctor or nurse about any concerns you have. Your doctor will want to know how you are feeling generally, and to check you are recovering from any side effects of treatment. We have more information about follow-up.


Getting support

Everyone has their own way of dealing with 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 call our cancer support specialists free on 0808 808 00 00. The organisations below also offer information and support:

  • Bloodwise offers support and information to people affected by blood cancers, including lymphoma.
  • 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.