saudigastro.com/patients/gi-lymphoma
Category
Serious
Red flags
4
This article is educational and does not replace your doctor's advice. Seek urgent care for any red-flag symptoms.
What is it?
Lymphocytes are white blood cells that fight infection and live in lymph nodes and in the lining of the gut. Lymphoma happens when these cells grow out of control. GI lymphoma most often involves the stomach, followed by the small bowel and the colon. There are many types. Some are slow-growing (low grade), such as MALT lymphoma of the stomach, which is linked to Helicobacter pylori infection. Others, such as diffuse large B-cell lymphoma, grow faster and need prompt treatment. The type is decided by examining a tissue sample.
How common is it?
GI lymphoma is uncommon compared with other digestive cancers. It can occur at any adult age, and certain types are more frequent in people with long-standing infection, coeliac disease or a weakened immune system.
Why does it happen?
The cause is often not known. Long-standing Helicobacter pylori infection is a recognised cause of stomach MALT lymphoma. Coeliac disease that is poorly controlled can be linked to a type of small bowel lymphoma. A weakened immune system (for example after organ transplant, with HIV, or from some immune-suppressing medicines) and some inflammatory conditions can raise the risk. Most people with these conditions will never develop lymphoma.
Symptoms
- Ongoing belly pain or discomfort
- Feeling full quickly, nausea or vomiting
- Loss of appetite and unplanned weight loss
- Fever, drenching night sweats and tiredness (sometimes called "B symptoms")
- Black stools or signs of bleeding and anaemia, such as pallor and breathlessness
- Diarrhoea or a change in bowel habit
- Swollen glands in the neck, armpit or groin
Red flags — seek urgent medical care
Sudden severe belly pain, a rigid belly, or fever with severe pain
Rarely, a lymphoma can weaken the bowel wall and cause a hole (perforation). Call emergency services or go to the emergency department now.
Vomiting blood, black tarry stools, or fainting
Suggests significant bleeding. Go to the emergency department immediately.
Repeated vomiting with a swollen belly and no passage of wind or stool
May mean the bowel is blocked. Seek emergency care.
Fever, night sweats and weight loss together
This combination needs prompt medical assessment, within days rather than weeks.
How is it diagnosed?
The diagnosis is made by biopsy, usually taken during an upper endoscopy or colonoscopy, and examined by a specialist pathologist with special stains to identify the lymphoma type. Blood tests, CT or PET-CT scans and sometimes a bone marrow test show how far it has spread (the stage). For stomach MALT lymphoma, testing for Helicobacter pylori is part of the work-up. A blood doctor (haematologist) and a gastroenterologist usually plan care together. Your doctor decides which tests you need.
What the latest science says
For early stomach MALT lymphoma linked to H. pylori, treating the infection with antibiotics can lead to remission in many patients without any cancer treatment, and this is now the standard first step. Faster-growing types are usually treated with modern combination regimens, often including antibody medicines, and surgery is now needed less often than in the past.
Outlook — what to expect
The outlook depends on the lymphoma type and stage. Low-grade types, especially stomach MALT lymphoma, often do very well and can sometimes be controlled for many years. Faster-growing lymphomas can often be cured or put into long remission with treatment, and starting early helps. Your haematology team can explain what to expect for your type.
Treatment
Habits & Lifestyle
Daily habits support you through diagnosis and treatment.
- Keep a record of symptoms such as fever, sweats, weight and bleeding, and bring it to appointments
- Take every course of treatment, including antibiotics for H. pylori, exactly as prescribed
- Report fever promptly during chemotherapy, because infections can become serious quickly
- Rest when you need to and stay gently active
- Do not smoke
Diet
The aim is to keep your weight and strength up during treatment.
- Eat small, frequent, energy- and protein-rich meals if appetite is poor
- Ask for a dietitian referral if you are losing weight
- During chemotherapy follow your team's food-safety advice, such as thoroughly cooking meat and eggs and washing produce
- If you have coeliac disease, keep strictly to a gluten-free diet
Medications
Your haematology and gastroenterology team will choose treatment based on the type and stage of lymphoma.
- Antibiotics and acid-lowering medicine to clear H. pylori in stomach MALT lymphoma
- Chemotherapy and antibody-based treatments for faster-growing or more widespread lymphoma
- Medicines to prevent nausea and protect against infection are often given alongside treatment
- Do not stop or change treatment on your own, and tell your team about all other medicines and herbal products you take
Procedures & Surgery
Procedures are used mainly for diagnosis and, in selected cases, to manage complications.
- Endoscopy and colonoscopy with biopsies confirm the diagnosis and track the response
- Repeat endoscopy is used to check that H. pylori has gone and that the lymphoma is responding
- Radiotherapy is sometimes used for localised disease
- Surgery is now needed mainly for complications such as perforation, bleeding or blockage
Living with the condition
- Follow-up visits and scans continue after treatment to watch for return of the lymphoma.
- Emotional support matters. Ask your team about counselling or patient support groups.
Questions to ask your doctor
Save this list or print it before your appointment — doctors appreciate prepared patients.
- What type and stage of lymphoma do I have?
- Is H. pylori involved, and will treating it be enough at first?
- What is the treatment plan and how long will it last?
- What side effects should I expect and which need urgent attention?
- How will you check that treatment is working?
- How often will I need follow-up after treatment?
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Status: Approved for publication by SGA; individual clinician review is ongoing · Published 24/04/2026
For general education only; it does not replace your doctor’s advice. Individual clinician review of this guide is ongoing. SGA clinician? Review this guide