The British Society of Haematology (BSH) just released a clinical practice guideline regarding the diagnosis and management of patients who have primary mediastinal B-cell lymphoma (PMBCL). The guideline, The Diagnosis and Management of Primary Mediastinal B-Cell Lymphoma, features 24 recommendations regarding first-line treatment, chemoimmunotherapy treatment response assessment, radiotherapy consolidation after first-line chemoimmunotherapy, management of relapsed PMBCL, and follow-up. Additionally, the guideline also discusses PMBCL presentation, diagnosis and pathobiology of PMBCL, fertility and pregnancy, and more.

Today, we’re outlining the recommendations included in The Diagnosis and Management of Primary Mediastinal B-Cell Lymphoma. Recommendations are organized by section. To view the complete 2026 BSH PMBCL guideline, view the full-text version.

Recommendations from 2026 BSH Guideline on PMBCL

First-Line Treatment:

  • Offer participation in a clinical trial wherever possible.
  • Offer R-CHOP-14 × 6 or DA-R-EPOCH × 6.
  • R-CHOP-21 is not recommended.
  • Thromboprophylaxis is recommended in view of the high thrombotic risk.
  • Anti-microbial prophylaxis is recommended as per local practice.

Chemoimmunotherapy Treatment Response Assessment:

  • Use conventional OSEM PET reconstruction techniques or specific research-accredited reconstructions for reporting the Deauville score on response assessment scans.
  • There are no current data to support a change of treatment as a result of interim PET response; therefore, the modality of interim imaging should be as per local clinical practice to assess response.

Radiotherapy Consolidation After First-Line Chemoimmunotherapy:

  • Do not offer radiotherapy for patients with DS 1–3 following chemoimmunotherapy.
  • Re-biopsy is recommended if feasible for all DS 4 and DS 5 patients at the EOT.
  • MDT discussion is essential to review the following:
    • The heterogeneity of the DS 4 group—there is more concern regarding patients with SUV nearly 2× that of liver compared to just above liver.
    • The site of disease and risk of radiotherapy.
    • Patient factors such as age and sex.
  • A personalised approach to balance the risk versus benefit of surveillance PET-CT or radiotherapy consolidation is required for patients with DS 4 at EOT.
  • Patients with DS 4 at EOT should be offered consultation with a clinical (radiation) oncologist to discuss radiotherapy versus surveillance imaging.
  • Discuss all patients with DS 5 at EOT at an MDT and perform a biopsy if possible.
    • Offer systemic treatment as for relapsed disease for patients with DS 5.
    • Radiotherapy alone can be considered if there is limited single residual uptake on PET-CT without progression or if the patient is unfit for systemic chemotherapy.

Management of Relapsed PMBCL:

  • Offer participation in a clinical trial wherever possible.
  • Offer CD19-directed targeted chimeric antigen receptor (CAR) T-cell (CAR-T) therapy (liso-cel) as second-line treatment if the patient has relapsed within 12 months.
  • Offer CD19-directed CAR T-cell therapy (axi-cel or liso-cel) as third or subsequent treatment line.
  • If available, consider the unlicensed combination of a PD1 inhibitor with brentuximab vedotin for patients with disease progression following CAR-T or autologous transplant.
  • Consider radiotherapy to localised sites of chemotherapy refractory disease.
  • Consider CD20-directed bispecific antibody with epcoritamab or glofitamab as a third or subsequent line of treatment line.
  • Consider loncastuximab as a third or subsequent line of treatment.
  • Consider allogeneic transplant for occasional patients who have failed multiple lines of treatment including CAR-T.

Follow-Up:

  • Consider discharge back to primary care for patients who are 24 months following end of treatment and who remain in remission.
  • Potential long-term complications should be outlined to patients and primary care health care professionals.
  • Do not perform surveillance imaging in asymptomatic patients.

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