MALT lymphoma

MALT lymphoma is a type of non-Hodgkin lymphoma (NHL). MALT stands for mucosa associated lymphoid tissue. It starts in the mucosa which lines some body organs and cavities.

It is a type of NHL called marginal zone lymphoma.  MALT lymphoma is also called extranodal marginal zone lymphoma.

MALT lymphoma usually grows slowly. Most people have early stage (localised) MALT lymphoma when they are diagnosed. The outlook is good, even when the lymphoma is quite widespread.

What is MALT lymphoma?

MALT lymphoma is a type of B cell non-Hodgkin lymphoma (NHL).

Lymphoma develops when white blood cells called lymphocytes  grow out of control. They move around your body in your blood and your lymphatic system . 

The lymphatic system is an important part of our immune system. It has tubes that branch through all parts of the body.

These tubes are called lymph vessels or lymphatic vessels and they carry a straw coloured liquid called lymph. This liquid circulates around the body tissues. It contains a high number of white blood cells (lymphocytes) which fight infection.

There are two types of lymphocytes: T lymphocytes (T cells) and B lymphocytes (B cells). 

MALT lymphoma develops when the body makes abnormal B lymphocytes. So it is a type of B cell lymphoma. 

MALT stands for mucosa associated lymphoid tissue. The mucosa is the moist tissue that lines some organs and body cavities, including the nose, mouth, lungs, and digestive tract . Lymphoid tissue is body tissue that contains lymphocytes. 

It is a type of marginal zone lymphoma. These lymphomas develop in an area at the edge of lymphoid tissue called the marginal zone. MALT lymphomas are the most common type of marginal zone lymphoma.

MALT lymphoma starts in the body organs, and not in the lymph nodes. Doctors also call it extranodal marginal zone lymphoma. Extranodal means outside the lymph nodes.

These lymphomas are slow growing (low grade). They most often develop in the stomach and are called gastric MALT. But they can also develop in the lung, thyroid, salivary glands, eye, skin or soft tissues. These lymphomas are called non gastric MALT.

Symptoms of MALT lymphoma

Your symptoms depend on where the MALT lymphoma starts. You might not have any symptoms. MALT lymphoma develops outside your lymph nodes. So it doesn't usually cause swollen lymph nodes.

MALT lymphoma most often develops in the stomach and is called gastric MALT lymphoma. Symptoms of gastric MALT lymphoma include:

• indigestion or heartburn
• weight loss
• feeling or being sick
• tummy pain 

MALT lymphoma that develops in another part of your body will have different symptoms. For example, MALT lymphoma developing in the lung can cause a cough or shortness of breath.

Who gets MALT lymphoma?

MALT lymphoma is most often diagnosed in older people. It can be linked to certain infections or autoimmune conditions . For example:

• MALT lymphoma of the stomach is often linked to a chronic stomach infection caused by the bacteria Helicobacter pylori
• MALT lymphoma of the salivary gland is often linked to an autoimmune disease called Sjogren’s syndrome
• MALT lymphoma of the thyroid can be inked to a condition of the thyroid called Hashimoto’s thyroiditis

Getting diagnosed

The main test to diagnose MALT lymphoma is a biopsy .  A doctor removes a sample from the affected area. They send it to the laboratory for a specialist to look at it under a microscope. How you have the biopsy depends on where the suspected lymphoma is. 

For suspected gastric MALT lymphoma you have a gastroscopy. This is also called an endoscopy or oesophago gastric duodenoscopy. This is when the doctor passes a thin tube (endoscope) through your mouth. They can look at your stomach and take biopsies of any abnormal looking tissue.

For other parts of your body you might have:

• a bronchoscopy - to take a biopsy from your lung
• a colonoscopy - to take a biopsy from your bowel

You usually also have some blood tests. For gastric MALT lymphoma you have a test to check for the bacteria Helicobacter pylori.

If your doctor diagnoses MALT lymphoma, you usually have further tests to see where it is in your body (the stage). These tests depend on what type of MALT lymphoma you have. They might include:

• a CT scan
• an ultrasound scan
• an MRI scan
• an x-ray

Other tests for staging MALT lymphoma include a PET-CT scan and a bone marrow test . 

Stages and grades of MALT lymphoma

Grade

Grade describes how the cells look under a microscope.  Your grade tells the doctor how quickly the lymphoma is likely to grow and spread. Doctors put NHL into 2 grades:

• low grade (slow growing)
• high grade (fast growing)

MALT lymphoma is usually slow growing and called a low grade lymphoma. Doctors also call this indolent lymphoma.

Transformation

Low grade lymphomas can sometimes change into a faster growing (high grade) lymphoma. Doctors call this transformation. This isn't very common for MALT lymphomas, but they can sometimes transform into a high grade lymphoma.

Treatment when a low grade lymphoma transforms is usually the same treatment as for high grade lymphoma. This is usually a combination of chemotherapy drugs and you might also have rituximab. 

Stage

You have tests to find out the number of places in your body affected by lymphoma and where these are. This is your stage. Doctors use your stage to plan your treatment.

There are different systems for staging NHL. For gastric MALT lymphoma, doctors might use a staging system that measures how far the lymphoma has grown into the stomach lining. Your doctor can tell you more about your stage, and what it means.

Generally, for NHL there are 4 main stages. Or your doctors might talk about early (limited) stage and advanced stage lymphoma.

Treatment for MALT lymphoma

Treatment for MALT lymphoma usually works well. Your treatment depends on:

• whether your lymphoma is linked to an infection
• where your lymphoma is (the stage)
• your symptoms

The main treatments

The main treatments are:

• treating infections linked to the lymphoma
• radiotherapy
• chemotherapy combined with a targeted cancer drug  - doctors call this chemoimmunotherapy

Treating infection

Most cases of gastric MALT lymphoma are linked to the bacteria Helicobacter pylori (H. pylori). This infection causes inflammation of the stomach lining.

You have tests to check for H. pylori. You then take antibiotics and a treatment to reduce the amount of acid made by the stomach.

This treatment works well for many people with gastric MALT lymphoma. You often don't need any other treatment. But it can take as long as a year for the lymphoma to go.

Your doctor monitors you closely after the antibiotic treatment. You have an endoscopy  about 3 to 6 months after the antibiotic treatment finishes. This is to look for signs of the lymphoma. You continue to have regular endoscopies after you finish the treatment.

If you still have signs of lymphoma, or it comes back, you might have radiotherapy or chemoimmunotherapy. This depends on how much lymphoma there is and what symptoms you have.

Other types of MALT lymphoma

Some other types of MALT lymphoma can be linked to infection. So your doctor might recommend antibiotics depending on your situation.

If you need treatment

You might not start radiotherapy or chemoimmunotherapy straight away if your lymphoma isn't causing any symptoms. 

You have regular check ups instead. This is called active monitoring, or watch and wait.

How often you have check ups depends on your situation. For gastric MALT lymphomas, you have regular endoscopies.

You usually only start treatment when you have symptoms that are bothering you. When the symptoms start, you might have one of the treatments below.

Radiotherapy

Radiotherapy uses high energy waves similar to x-rays to kill cancer cells.

You might have radiotherapy if your MALT lymphoma is only affecting one or two areas close together and is not wide spread. Doctors call this localised lymphoma. You might have it for:

• localised gastric MALT lymphoma that has come back or not gone away with antibiotics
• other types of localised MALT lymphomas

Chemotherapy and targeted cancer drugs (chemoimmunotherapy)

You might have chemotherapy combined with a targeted cancer drug called rituximab. Doctors call this combination chemoimmunotherapy. Or you might have rituximab on its own.  

Chemotherapy uses anti cancer (cytotoxic) drugs to destroy cancer cells. Rituximab is a type of monoclonal antibody (MAB) . MABs are a type of targeted drug therapy.  

Common treatment combinations include:

• rituximab with bendamustine
• rituximab with CVP (cyclophosphamide, vincristine, and prednisolone)
• chlorambucil and rituximab 

You have the chemoimmunotherapy drugs on certain days. This is usually over 3 or 4 weeks. Each 3 or 4 week period is called a cycle of treatment. How many cycles you have depends on your situation.

Some people might continue to take rituximab on its own. This is called maintenance treatment .

Survival for MALT lymphoma

MALT lymphoma is usually slow growing and treatment can work very well. 

The best person to talk to you about your outlook or prognosis is your doctor. Not everyone wants to know, people cope differently with their lymphoma and want different information.

Survival depends on many factors. So no one can tell you exactly how long you will live. Your doctor might be able to give you some guide, based on their knowledge and experience.

Research and clinical trials

Your doctor might ask if you’d like to take part in a clinical trial. Doctors and researchers do trials to:

• make existing treatments better

• develop new treatments

Coping with NHL

It can be difficult finding our you have NHL. Some people find it can be particularly worrying in the run up to check up appointments.

Advice and support is available to help you cope with NHL and its treatment.

Our discussion forum Cancer Chat is a place for anyone affected by cancer. You can share experiences, stories and information with other people who know what you are going through.

Cancer Research UK nurses