• HTLV-1 (human T-lymphotropic virus type 1): A virus that infects T cells, is passed mainly through breastfeeding and sexual contact, and causes a lymphoma decades later in a small minority of the people it infects.
• Intrathecal therapy (lumbar puncture, Ommaya reservoir): Giving drugs directly into the fluid around the brain and spinal cord, by needle in the lower back or through a small reservoir under the scalp, because most drugs cannot cross from the blood into that space.
• 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.
• Infection prophylaxis in lymphoma: PJP, herpes, fungal risk and vaccination: Several lymphoma treatments knock out the part of the immune system that keeps a particular lung infection, Pneumocystis, at bay.
• 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.
• B-cell, T-cell and NK-cell lymphoma: The first thing a lymphoma report says is which kind of lymphocyte the cancer came from.
• Stem cell transplant in lymphoma: what it is still for: An autologous transplant is very high-dose chemotherapy followed by the patient's own stored stem cells to rescue the bone marrow.
• Lugano classification / Ann Arbor staging: The Lugano classification is the lymphoma staging system: stage I to IV by how many lymph node regions and organs are involved, with PET-based response criteria.
• 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.

Testing for the virus, which decides the diagnosis: HTLV-1 serology belongs in the work-up of any T-cell lymphoma or leukaemia in a person who comes from, or whose parents come from, south-western Japan, the Caribbean, west or central Africa, parts of South America, Iran or Romania. Without the test the disease is reported as peripheral T-cell lymphoma not otherwise specified and treated on a pathway that does not fit it. A positive test is followed by confirmation that the virus is clonally integrated in the tumour cells, because asymptomatic infection is common in those populations and does not by itself mean lymphoma.

Biomarker results to ask for: HTLV-1 serology, and confirmation that the virus is clonally integrated in the tumour cells, The Shimoyama type (acute, lymphoma, chronic or smouldering), which is the main treatment decision, Serum calcium and lactate dehydrogenase, both part of the subtype definition, A CD4-positive, CD25-positive, CCR4-positive phenotype with loss of CD7, Strongyloides screening before immunosuppressive treatment, because hyperinfection is fatal, Examination of the spinal fluid in the aggressive types, in which involvement of the central nervous system is common.

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

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

• Working out which of the four types it is: The subclassification proposed by Shimoyama and adopted by the international consensus meetings divides the disease into acute, lymphoma, chronic and smouldering types, using the count of circulating tumour cells, the lactate dehydrogenase, the calcium and the sites involved. It is the first decision and it changes everything: the chronic and smouldering types without unfavourable features are watched, while the acute and lymphoma types are treated at once. The consensus report sets out prognostic factors and a set of response criteria specific to this disease, which is why trials in it are not reported like trials in other lymphomas. (HTLV-1 (human T-lymphotropic virus type 1), Lugano classification / Ann Arbor staging, Watch and wait in lymphoma: when the right treatment is none yet)
• What has to be looked for before and during treatment: Three things that belong to this disease and not to the rest of the family. Calcium, which can be very high because the tumour makes parathyroid hormone-related protein, and which may present as confusion, thirst or kidney failure before the lymphoma is recognised. Strongyloides stercoralis, because the immune suppression caused by the virus allows hyperinfection, which is fatal and is prevented by screening and treating before immunosuppressive therapy. And the central nervous system, which is commonly involved in the aggressive types and is examined by lumbar puncture. (HTLV-1 (human T-lymphotropic virus type 1), Intrathecal therapy (lumbar puncture, Ommaya reservoir), Infection prophylaxis in lymphoma: PJP, herpes, fungal risk and vaccination)
• Adult T-cell leukaemia/lymphoma (HTLV-1): Caused by human T-lymphotropic virus type 1, acquired in infancy through breastfeeding and causing lymphoma after a latency of decades in a small percentage of those infected. It occurs in people from south-western Japan, the Caribbean, west and central Africa, parts of South America, Romania and Iran, and it is the reason HTLV-1 serology belongs in the work-up of any T-cell lymphoma in a person from those populations. Four clinical types, and they are treated differently. Smouldering and chronic types without unfavourable features are watched, or treated with zidovudine and interferon alfa, which produces long remissions in the leukaemic types; antiviral therapy does not work in the lymphoma type. Acute and lymphoma types are treated with intensive chemotherapy. JCOG9801 randomised 118 patients with aggressive disease to six courses of VCAP-AMP-VECP or eight courses of biweekly CHOP, both with G-CSF and intrathecal prophylaxis: the complete response rate was 40 against 25 per cent and three-year overall survival 24 against 13 per cent, with more toxicity in the intensive arm (grade 4 neutropenia 98 against 83 per cent, grade 3 or 4 infection 32 against 15 per cent). VCAP-AMP-VECP is standard in Japan; outside Japan, CHOP or CHOEP with early referral for allogeneic transplant is more usual. Allogeneic stem cell transplant is the only treatment that cures a minority, and it is offered early because remissions are short. Mogamulizumab, an anti-CCR4 antibody first approved in Japan in 2012, produces responses in relapsed aggressive disease: in the updated phase 2 analysis of 26 relapsed patients, median progression-free survival was 5.2 months and median overall survival 14.4 months, and outcomes were better in patients who developed a rash of grade 2 or more, a signal that is being read as an immune effect rather than a side effect alone. Central nervous system involvement is common and intrathecal prophylaxis is given. (Mogamulizumab, Interferon alfa-2a/2b, Cyclophosphamide, Doxorubicin, Vincristine, Prednisone, Etoposide, Carboplatin, Allogeneic stem cell transplantation, Intrathecal therapy (lumbar puncture, Ommaya reservoir), Stem cell transplant in lymphoma: what it is still for)

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