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6 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
A slow-growing MALT lymphoma that grows in the lining of the stomach, usually caused by a long-standing infection with the bacterium Helicobacter pylori. It is the one lymphoma that is often cured by a fortnight of antibiotics, and a single chromosome change predicts the minority in whom antibiotics will not work.
What it is. The stomach has no lymphoid tissue of its own. Chronic infection with Helicobacter pylori creates some, as part of the immune response to the bacterium, and over years a clone of B cells in that tissue can become a lymphoma. The lymphoma depends on the signals the infection provides, which is the reason for the treatment that follows.
How it differs from its parent. Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue arises at many sites and the sites differ genetically: WHO-HAEM5 sets out that ocular adnexal disease commonly carries mutation or deletion of TNFAIP3, salivary gland disease carries recurrent GPR34 mutation, and thyroid disease carries deleterious mutations of CD274, TNFRSF14 or TET2. What the stomach has, and only the stomach and the lung among the common sites, is the translocation t(11;18)(q21;q21), which fuses BIRC3 to MALT1. WHO-HAEM5 states its clinical application in one sentence: that fusion identifies the cases of gastric extranodal marginal zone lymphoma that will not respond to eradication of Helicobacter pylori.
| Setting | Approach | Guideline |
|---|---|---|
| Diagnosis and staging | Endoscopy with multiple biopsies from the abnormal area and from every region of the stomach, because the lymphoma is patchy and a single biopsy can miss it. Helicobacter pylori is sought by more than one method. Endoscopic ultrasound measures how deep the lymphoma goes, which predicts whether antibiotics alone will work; in a prospective comparison against the resected stomach it judged the depth correctly in 91.5 per cent of cases. Fluorescence in situ hybridisation for t(11;18) is done where it will change the plan. Staging uses the gastrointestinal system that counts depth and node involvement rather than the ordinary node-region count. | not mapped |
| First treatment: eradicate the bacterium | A standard eradication regimen of a proton pump inhibitor with two antibiotics, chosen by local resistance patterns, is the first treatment for Helicobacter pylori-positive disease and is also offered in negative disease, where a minority still respond. Success is confirmed by a breath or stool test after treatment, and the lymphoma is then followed by repeated endoscopy and biopsy over months, because regression is slow. In the prospective series of 120 patients with stage I disease, 80 per cent achieved complete histological remission and 80 per cent of those remained in continuous remission at a median follow-up of 75 months. | not mapped |
| Residual disease on a follow-up biopsy | Residual lymphoma on a biopsy after successful eradication is common and usually does not need treatment. In the same series, 17 per cent of those who had reached complete remission later showed histological residual disease; they were watched rather than treated, and all of them entered a second remission. A persisting monoclonal band in the immunoglobulin genes is also common and is not by itself a reason to treat. What does need action is growth, new symptoms, or large cells appearing on the biopsy. | not mapped |
| When antibiotics do not work, or cannot | Radiotherapy to the stomach at a low dose is the usual next step for disease that stays localised, and anti-CD20 antibody treatment, alone or with chemotherapy, for disease that has spread or that carries t(11;18) and is therefore unlikely to respond to eradication. Surgery has essentially no role at any stage, which is the main difference from gastric cancer. The regimens, the doses and the evidence are on the MALT lymphoma page and in the treatment layer of this family. | not mapped |