T-cell lymphoma

Major systemic mature entities include PTCL not otherwise specified, nodal T-follicular-helper (TFH) cell lymphomas and systemic anaplastic large-cell lymphoma (ALCL). TFH lymphomas include the angioimmunoblastic type, which older reports may call AITL. These names describe different biology, not merely different stages.

Other entities include HTLV-1-associated adult T-cell leukemia/lymphoma, hepatosplenic and intestinal T-cell lymphomas. Cutaneous T-cell lymphoma has its own staging and treatment. T-lymphoblastic lymphoma is an immature-cell disease generally treated through an ALL-type pathway.

An adequate tissue sample is important because reactive immune cells, infections and other lymphomas can mimic PTCL. Review may include T-cell markers, CD30, ALK, TFH markers, EBV studies, T-cell receptor clonality and selected genetics. No single marker replaces the full pathological assessment.

For ALCL, distinguish ALK-positive from ALK-negative disease and systemic disease from primary cutaneous or breast-implant-associated ALCL. Their prognosis and treatment differ. HTLV-1 testing is relevant when the clinical and epidemiological setting raises the possibility of adult T-cell leukemia/lymphoma.

Systemic disease work-up may include PET/CT, blood counts, LDH, organ function and marrow evaluation. The team assesses symptoms, performance status, infection and organ involvement, rather than choosing treatment from stage alone.

TFH-type disease may cause rash, immune abnormalities or autoimmune cytopenias. Some aggressive T/NK-cell diseases can trigger hemophagocytic lymphohistiocytosis (HLH). Persistent high fever, worsening counts, liver dysfunction or rapid deterioration deserves urgent assessment for disease and infection together.

CHOP or a related anthracycline-based program remains a common starting point for several systemic PTCL subtypes; adding etoposide is considered in selected patients. The evidence and toxicity balance differ by subtype and fitness, so more intensive chemotherapy is not automatically appropriate.

Brentuximab vedotin plus CHP is an important CD30-directed first-line option. The US indication includes untreated systemic ALCL and other CD30-expressing PTCL. ECHELON-2 showed durable survival benefits overall, but most participants had systemic ALCL; certainty is not identical in every smaller subtype.

CHP omits vincristine when brentuximab is used, rather than simply adding the new drug to full CHOP. Neuropathy, low counts and infection prevention remain part of planning.

Early mycosis fungoides may be treated with skin-directed measures, whereas advanced cutaneous disease or Sézary syndrome needs a different systemic assessment. A skin biopsy showing a T-cell process does not automatically justify the same treatment used for nodal PTCL.

ALK-positive systemic ALCL can have a target-specific option at relapse. The US crizotinib indication covers children aged at least one year and young adults with relapsed/refractory ALK-positive systemic ALCL; it is not a blanket indication for all adult T-cell lymphomas.

For extranodal NK/T-cell lymphoma, EBV assessment, asparaginase-containing therapy and coordinated radiation are central considerations. Follow the dedicated NK/T-cell guide rather than transferring a nodal PTCL plan.

Autologous transplantation in first response may be considered for selected systemic PTCL, but it is not uniformly required for every subtype or every risk group. The quality of remission and fitness matter, and the evidence includes important nonrandomized experience.

At relapse, achieving disease control can open a route to allogeneic transplantation in selected patients. Donor availability, infection, organ function and graft-versus-host risks need early discussion. A medicine used as a bridge has a different purpose from indefinite disease control.

Repeat biopsy can confirm subtype and target expression at relapse. Treatment may include a subtype-active drug, salvage chemotherapy or a trial, chosen around prior exposure and a possible transplant plan. A response rate from a single-arm study does not prove superiority to another medicine.

China has approved the selective JAK1 inhibitor golidocitinib for adults with relapsed/refractory PTCL after at least one systemic line. JACKPOT8 provides the disease-specific phase II evidence. Blood-count suppression and serious infection are relevant risks despite oral administration.

Japan authorizes the EZH1/2 inhibitor valemetostat for relapsed/refractory PTCL, supported by VALENTINE-PTCL01. It is a different medicine from tazemetostat and should not inherit that drug’s regulatory status. Regional approval does not guarantee suitability or access in every country.

JACKPOT26 explored golidocitinib maintenance after response to first-line therapy. Its phase II findings support further study; they are not the same as the approved relapsed/refractory indication or proof that every responder needs maintenance.

CD7-directed CAR-T is being studied in selected T-cell lymphomas. Recent early-phase studies and analyses of antigen-negative relapse underline the need to confirm target expression, exact mature versus precursor disease, immune-reconstitution risks and any planned transplant after response.

B-cell CAR-T results cannot be imported into this setting. A report combining T-ALL and lymphoma requires separate reading of the lymphoma patients; manufacturing strategy and immune toxicity also differ.

Bring full pathology and available tissue, CD30/ALK and TFH results, viral tests, PET/CT images, prior drug schedules and response dates. Include skin findings, immune complications and prior infections, not just a list of medicines.

Ask whether the diagnosis is sufficiently specific, whether the proposed treatment is supported in that subtype, whether a trial offers a relevant opportunity, and whether remission should be used to proceed to transplantation.