MALT lymphoma: symptoms, causes, treatment and outlook

Cancer Research UK says your symptoms depend on where the MALT lymphoma starts, and you might not have any symptoms. Because it develops outside the lymph nodes it does not usually cause swollen lymph nodes.

MALT lymphoma most often develops in the stomach (gastric MALT lymphoma). Cancer Research UK lists the symptoms of gastric MALT lymphoma as indigestion or heartburn, weight loss, feeling or being sick, and tummy pain. MALT lymphoma that develops in another part of the body has different symptoms; for example in the lung it can cause a cough or shortness of breath.

These symptoms are common and usually have a cause other than lymphoma. See a GP if they last or keep returning, and tell them about unexplained weight loss.

MALT lymphoma is a type of B cell non-Hodgkin lymphoma (NHL), according to Cancer Research UK. NHL is a group of blood cancers that affect white blood cells called lymphocytes. 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.

It is a type of marginal zone lymphoma, which develops in an area at the edge of lymphoid tissue called the marginal zone, and MALT lymphomas are the most common type of marginal zone lymphoma. Cancer Research UK says around 2,600 people are diagnosed with marginal zone lymphoma in the UK each year, and more than 60% of marginal zone lymphomas are MALT lymphomas.

MALT lymphomas are usually slow growing (low grade, also called indolent). Cancer Research UK says most people have early stage (localised) disease when diagnosed and the outlook is good.

Cancer Research UK says MALT lymphoma is most often diagnosed in older people and can be linked to certain infections or autoimmune conditions. The links it describes are:

• Stomach: often linked to a chronic stomach infection caused by the bacteria Helicobacter pylori, which causes inflammation of the stomach lining.

• Salivary gland: often linked to an autoimmune disease called Sjogren's syndrome.

• Thyroid: can be linked to a thyroid condition called Hashimoto's thyroiditis.

The main test is a biopsy: a doctor removes a sample from the affected area and a specialist examines it under a microscope. For suspected gastric MALT lymphoma you have a gastroscopy (also called an endoscopy), in which a thin tube is passed through your mouth so the doctor can look at your stomach and take biopsies of abnormal-looking tissue. For other sites you might have a bronchoscopy (lung) or colonoscopy (bowel).

You usually also have blood tests, and for gastric MALT lymphoma a test for Helicobacter pylori. If lymphoma is diagnosed, tests to find the stage may include a CT scan, ultrasound, MRI, X-ray, PET-CT scan and bone marrow test, depending on the type (Cancer Research UK). For gastric MALT, doctors might use a staging system that measures how far the lymphoma has grown into the stomach lining.

NICE guideline NG52 covers diagnosing, staging and managing non-Hodgkin lymphoma in people aged 16 and over, and includes MALT lymphoma among the types it covers.

Cancer Research UK says treatment usually works well, and depends on whether the lymphoma is linked to an infection, where it is (the stage) and your symptoms. The main treatments are treating infections linked to the lymphoma, radiotherapy, and chemotherapy combined with a targeted cancer drug (chemoimmunotherapy).

Most cases of gastric MALT lymphoma are linked to Helicobacter pylori, so you have tests to check for it and then take antibiotics plus a treatment to reduce the amount of acid made by the stomach. Cancer Research UK says this works well for many people and you often do not need any other treatment, but it can take as long as a year for the lymphoma to go.

Your doctor monitors you closely: you have an endoscopy about 3 to 6 months after the antibiotics finish, to look for signs of lymphoma, and continue to have regular endoscopies afterwards. If there are still signs of lymphoma, or it comes back, you might have radiotherapy or chemoimmunotherapy, depending on how much lymphoma there is and your symptoms. Other types of MALT lymphoma can also be linked to infection, so antibiotics may be considered.

Cancer Research UK says MALT lymphoma usually grows slowly, the outlook is usually good even when it is quite widespread, and treatment can work very well. It adds that survival depends on many factors, that no one can tell you exactly how long you will live, and that your doctor is best placed to talk about your own outlook; not everyone wants to know.

Low grade lymphomas can sometimes change (transform) into a faster growing, high grade lymphoma. Cancer Research UK says this is not very common for MALT lymphomas but can happen, and that treatment is then usually the same as for high grade lymphoma, typically a combination of chemotherapy drugs with rituximab.

Cancer Research UK says MALT lymphoma is most often diagnosed in older people. The UK sources used for this page do not give specific guidance for children or for pregnancy. NICE guideline NG52 applies to people aged 16 and over. If you are pregnant or planning a pregnancy and are told you have lymphoma, ask your haematology team to involve your obstetric team from the start, because treatment choices and timing may differ.

Cancer Research UK acknowledges that finding out you have NHL can be difficult and that some people find the run-up to check-up appointments particularly worrying. It points to practical and emotional support, its information nurses, and its online forum Cancer Chat. Ask your clinical nurse specialist what support is available locally.

• See a GP if you have indigestion or heartburn that keeps returning, tummy pain, feeling or being sick, or weight loss without trying.

• Seek urgent advice from NHS 111 or your cancer team if you have been diagnosed with lymphoma and develop a high temperature, vomiting blood, black stools or severe tummy pain.

• Call 999 for severe breathlessness, collapse or vomiting a lot of blood.

• Tell your team about any new lumps, drenching night sweats or fevers.

A GP may arrange a gastroscopy or refer you to a specialist if symptoms suggest a stomach problem. If a biopsy shows MALT lymphoma, you are looked after by a haematology team (and for gastric disease usually a gastroenterology team too) in a hospital cancer service. Cancer Research UK says doctors may ask if you would like to take part in a clinical trial.

Private gastroscopy and haematology appointments are available. If you have a private biopsy that shows lymphoma, ask for your results to be shared with an NHS multidisciplinary team so that treatment and follow-up endoscopies are coordinated.