• Helicobacter pylori eradication as cancer treatment in gastric MALT lymphoma: Gastric MALT lymphoma is grown by a stomach bacterium, and killing the bacterium with a ten to fourteen day course of antibiotics cures most cases.
• The germinal centre: why lymphoma starts where antibodies are made: To make a better antibody, a B cell has to deliberately damage its own DNA while dividing fast, with its safety checks switched off.
• Staging a lymphoma of the stomach or bowel: A lymphoma that starts in the stomach or bowel is staged by how deep it goes into the wall and how far along the lymph node chain it has travelled, not only by how many node regions are involved.
• MYD88 L265P and CXCR4 mutations: One letter change in MYD88 (L265P) keeps a B-cell survival signal permanently on; it is found in more than nine in ten Waldenström's macroglobulinaemia, most primary CNS and testicular lymphomas and a poor-risk group of DLBCL, and it predicts that BTK inhibitors will work, while a second mutation in CXCR4 predicts that they will work more slowly.
• Living with an indolent lymphoma rather than being cured of one: Slow-growing lymphomas are usually controlled rather than cured: treatment works, the disease goes away for a while, and at some point it comes back and is treated again.
• Watch and wait in follicular lymphoma: being told you have cancer and that nobody will treat it: For a slow-growing lymphoma that is not causing problems, treating straight away has not been shown to help people live longer, so the usual plan is regular checks and treatment later.
• Watchful waiting, and how it differs from active surveillance: Two things that sound the same and are not.
• Low antibodies and infection risk for years after anti-CD20 and bispecific antibodies: Treatments that remove B cells also remove the cells that make antibodies, and the effect can last for years after the last dose.
• Watch and wait in lymphoma: when the right treatment is none yet: For slow-growing lymphomas that are not causing symptoms, treating straight away does not help people live longer.
• Hypogammaglobulinaemia and infection risk after B-cell therapies: A shortage of antibodies because treatment has wiped out the B cells or plasma cells that make them, as CD19 CAR-T, CD20 antibodies and BCMA therapies deliberately do.

Biomarker results to ask for: Helicobacter pylori status (gastric), t(11;18) API2-MALT1 translocation, Immunophenotype: CD20 positive, CD5 and CD10 negative, FDG avidity (variable).

Scans and tests linked to this cancer: Cytogenetics and FISH, Histopathology & immunohistochemistry, Multidisciplinary tumour boards.

Bring copies of scan reports, pathology and blood results, and a list of every medicine and supplement.

• Localised at other sites: Involved-site radiotherapy (the FoRT trial tested the dose in follicular and marginal zone lymphoma). (FoRT, Marginal zone lymphoma)
• Gastric, H. pylori-positive: H. pylori eradication first, with endoscopic follow-up; radiotherapy if the lymphoma persists. (Marginal zone lymphoma)
• Gastric MALT lymphoma: a cancer cured by antibiotics: Helicobacter pylori eradication is the first treatment for every Helicobacter-positive gastric MALT lymphoma, whatever the stage, and it is a cure in most of them. The observation that made this possible was published in 1993, when eradication produced regression of the lymphoma in five of six patients, and it remains one of the very few instances in oncology in which a course of antibiotics is the definitive treatment of a malignancy. What is given: a standard triple or quadruple eradication regimen chosen by local resistance patterns, typically a proton pump inhibitor with two antibiotics for 10 to 14 days. Eradication is then confirmed, by urea breath test or stool antigen at least four weeks after antibiotics and two weeks off the proton pump inhibitor, because failure of eradication is the commonest reason for failure of the lymphoma to respond. What happens next: endoscopic and histological follow-up every three to six months. Regression is slow and can take twelve to eighteen months, so persistent histological disease in a patient whose Helicobacter has been eradicated and who has no symptoms is watched, not treated. The t(11;18) translocation predicts failure to respond to eradication and is worth testing where it is available. Helicobacter-negative gastric MALT lymphoma is still given eradication therapy in many centres, because some respond, but it is not relied on. (Regression of primary low-grade gastric MALT lymphoma after eradication of Helicobacter pylori, Helicobacter pylori eradication as cancer treatment in gastric MALT lymphoma, Watch and wait in lymphoma: when the right treatment is none yet, Endoscopy (EGD, EUS, ERCP), Marginal zone lymphomas: ESMO clinical practice guidelines)
• Gastric MALT lymphoma that does not respond to eradication, and MALT at other sites: Where the Helicobacter has been eradicated and the lymphoma persists and is causing symptoms or progressing, radiotherapy is the next treatment: about 24 Gy in 12 fractions to the stomach, which controls the disease in the great majority. Systemic treatment, usually rituximab alone or rituximab with chlorambucil or bendamustine, is used for disseminated disease or where radiotherapy is not possible. Surgery has no routine role. MALT lymphoma at other sites, salivary gland, thyroid, lung, skin, orbit, breast, is treated on the same principle: a localised, symptomatic site gets 24 Gy, an asymptomatic one can be watched, and disseminated disease gets rituximab-based systemic treatment. Ocular adnexal MALT is sometimes given doxycycline first for Chlamydia psittaci, with response rates that vary widely by region. Salivary gland MALT in Sjogren syndrome and thyroid MALT in Hashimoto thyroiditis are managed jointly with the specialty that treats the underlying autoimmune disease. The IELSG-19 trial is the randomised evidence for systemic treatment: five-year event-free survival was 68 per cent with chlorambucil and rituximab, 51 per cent with chlorambucil alone and 50 per cent with rituximab alone, with five-year overall survival of about 90 per cent in each arm. (Radiotherapy in lymphoma: involved-site fields, 24 Gy, 4 Gy and total skin electron therapy, Rituximab, Chlorambucil, Bendamustine, IMRT / IGRT (modern external beam), Marginal zone lymphomas: ESMO clinical practice guidelines)
• Disseminated or relapsed: Rituximab alone or with chlorambucil or bendamustine; zanubrutinib or lenalidomide-rituximab later (AUGMENT; MAHOGANY). (Rituximab, Chlorambucil, Bendamustine, Zanubrutinib, Lenalidomide, AUGMENT, A Study of Zanubrutinib Plus Anti-CD20 Versus Lenalidomide Plus Rituximab in Participants With Relapsed/Refractory Follicular or Marginal Zone Lymphom)

From the standard of care recorded for this cancer; which apply depends on your stage and biomarkers. Ask which the team recommends and why.