• 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.
• CNS prophylaxis in aggressive B-cell lymphoma, and the evidence against it: Some people with aggressive lymphoma are given extra methotrexate, into the spine or into a vein, to stop the lymphoma reaching the brain.
• Prognostic Index for T-cell lymphoma (PIT): A four-item score that estimates the outlook in nodal T-cell lymphoma, built because the index used for B-cell lymphoma separated these patients poorly.
• Epstein-Barr virus (EBV) in cancer: The common glandular-fever virus, carried lifelong by most adults, which in a minority of people drives nasopharyngeal cancer, some stomach cancers and several lymphomas.
• Nodal and extranodal lymphoma: A lymphoma that starts in a lymph node is called nodal; one that starts in an organ is called extranodal.
• The two lymphoma classifications of 2022 (WHO-HAEM5 and ICC): Since 2022 there have been two reference classifications of lymphoma rather than one, published within months of each other by overlapping groups of experts.
• The lymphoma regimen alphabet: R-CHOP, pola-R-CHP, DA-EPOCH-R, ABVD, BEACOPP and the rest: Lymphoma treatment is written in acronyms, one letter per drug.

Diagnosis, and telling it from its neighbour: Often made on small bowel resected as an emergency for perforation or obstruction. What separates it from enteropathy-associated T-cell lymphoma is the absence of coeliac disease, the monotonous small to medium cells rather than varied large ones, a CD8-positive and CD56-positive phenotype, and SETD2 mutation with JAK3 and STAT5B rather than JAK1 and STAT3. Neither carries Epstein-Barr virus, which separates both from NK/T-cell lymphoma of the gut.

Biomarker results to ask for: Monotonous small to medium-sized cells invading the lining of the bowel, which is the name and the diagnosis, A CD8-positive, CD56-positive phenotype in most cases, SETD2 mutation, and mutations of JAK3 and STAT5B, which separate it from enteropathy-associated T-cell lymphoma, Gains of 9q34 and loss of 16q12, shared with enteropathy-associated T-cell lymphoma, Absence of coeliac disease, which is the main clinical difference, Absence of Epstein-Barr virus, which separates it from NK/T-cell lymphoma of the gut.

Scans and tests linked to this cancer: FDG PET, Histopathology & immunohistochemistry.

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

• Systemic treatment, and how thin the evidence is: There is no randomised evidence of any kind. The largest real-world comparison took 50 patients who received systemic chemotherapy and compared a modified version of the Newcastle regimen developed for enteropathy-associated T-cell lymphoma, giving cyclophosphamide, doxorubicin, vincristine and prednisone alternating with ifosfamide, etoposide and epirubicin but leaving out the methotrexate, against ordinary chemotherapy of the same backbone: median progression-free survival 14.4 against 6.6 months and overall survival 28.7 against 11.7 months, with the regimen remaining an independent predictor of better progression-free survival after adjustment. The two-year cumulative incidence of relapse in the central nervous system was 12.1 per cent, which is what the omitted methotrexate had been intended to prevent. Entry into a trial is a reasonable first choice rather than a last resort. (Cyclophosphamide, Doxorubicin, Vincristine, Prednisone, Ifosfamide, Etoposide, Methotrexate, CNS prophylaxis in aggressive B-cell lymphoma, and the evidence against it, The lymphoma regimen alphabet: R-CHOP, pola-R-CHP, DA-EPOCH-R, ABVD, BEACOPP and the rest)

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