Primary mediastinal (thymic) large B-cell lymphoma: the decisions you may face
3 treatment settings, 3 with more than one named option. Each section lays out the options the standard of care names, what each is for, the trials behind them with their recorded results, the side effects and cautions on record, and questions to ask. Built from the cancer page's standard-of-care rows; nothing here is advice for your case.
First line
Dose-adjusted EPOCH-R for six cycles without radiotherapy, or R-CHOP for six cycles with PET-guided consolidation radiotherapy; end-of-treatment PET decides whether radiotherapy is needed (IELSG37).
Rituximab was the first antibody ever approved for cancer (1997). It made chemoimmunotherapy the CLL standard for a decade, and biosimilars keep it cheap and everywhere.
The red chemotherapy drug from a soil bacterium that is still the backbone of treatment for sarcoma, lymphoma and breast cancer, limited by cumulative heart damage.
Cyclophosphamide is an alkylating chemotherapy that damages DNA in dividing cells. It is part of CHOP for lymphoma, AC for breast cancer and VAC for childhood sarcomas, clears lymphocytes before CAR-T and prevents graft-versus-host disease after transplant; bladder bleeding, infertility and secondary leukaemia are its harms.
Etoposide is a chemotherapy from the mayapple plant, essential to curing testicular cancer (BEP), treating small-cell lung cancer, lymphomas, childhood sarcomas and leukaemias, and used in transplant conditioning.
A plant-derived chemotherapy from the Madagascar periwinkle that has been in almost every childhood leukaemia and lymphoma regimen since the 1960s.
Prednisone is the everyday steroid tablet in cancer care. It is the P in CHOP and MOPP for lymphoma, part of childhood leukaemia treatment, and taken with abiraterone in prostate cancer.
FDG PET is the standard PET scan. A radioactive sugar shows which tissues are burning glucose fast, which most cancers do.
- Universal availability
- Decades of validation
Scan after two cycles of chemotherapy; if the tumour has gone dark, give less treatment, and if not, give more. Hodgkin lymphoma pioneered this.
- Spares most patients bleomycin, radiation or intensified chemotherapy
- Identifies the minority who need escalation
- Primary mediastinal large B-cell lymphoma in complete metabolic response on PET after rituximab-based immunochemotherapy: consolidation mediastinal radiotherapy versus observation
Show survival figures (1)
Averages across everyone diagnosed, often years ago. Your stage, subtype, age, fitness and the treatment you receive matter more than the average, and the numbers are improving quickly.
- 30-month progression-free survival 96.7% (observation) vs 98.5% (radiotherapy) in patients with complete metabolic response; radiotherapy can be omitted.
Progression-free survival at 30 months (%): Observation 96.7 (n=132) vs Consolidation radiotherapy 30 Gy 98.5 (n=136) · source
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Infusion-related reactions (first infusion) · Historic lymphoma data; lower with premedication | 77% | - |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
- Cumulative dose: risk rises steeply above 400-550 mg/m² (see the anthracycline calculator).
- Reduce by 50% for bilirubin 20-50 µmol/L and 75% for 50-85 µmol/L.
- Reduce to 75% for CrCl 15-50.
- Fatal if given intrathecally: label all syringes.
- Non-specific: infection and inflammation are also hot
- Brain background
- Poor in indolent tumours
- Interim PET has imperfect positive predictive value (many PET2-positive patients are cured anyway)
- Omitting radiotherapy trades a few percent PFS for late-toxicity avoidance
- Between Rituximab, Doxorubicin, Cyclophosphamide and the other options, which do you recommend for me, and what about my case would make you choose differently?Why: Guidelines list several reasonable options; the choice turns on details of your tumour, your health and your priorities.
- What is each option trying to achieve: cure, long control, or relief of symptoms, and over what time?Why: The aim shapes how much side effect and disruption is worth accepting.
- How closely do I match the people in IELSG37, and does that change what the results mean for me?Why: Trial populations are selected; age, fitness, prior treatment and biomarkers all affect how far results carry.
- Which side effects of Rituximab are most likely for me, which are reversible, and which would make us stop?Why: The recorded rates below come from labels and trials; your own risk depends on dose, other medicines and your health.
- What happens if I delay, or decline this step for now? Is the decision reversible?Why: Some decisions can wait for a second opinion or a trial slot; others cannot. Knowing which is part of the choice.
- Does your recommendation follow the current guideline (NCCN Guidelines: B-Cell Lymphomas), and if it departs from it, why?Why: Departures from guidelines are sometimes right for an individual; they should be explained.
- For my situation (first line), which of the standard options do you recommend and why?Why: Guideline options include: Dose-adjusted EPOCH-R for six cycles without radiotherapy, or R-CHOP for six cycles with PET-guided consolidation radiotherapy; end-of-treatment PET decides whether radiotherapy is needed (IELSG37).
- Am I a candidate for Rituximab, Doxorubicin, Cyclophosphamide or related drugs, and what side effects should I expect?Why: Knowing the expected toxicities helps you plan work, family, and supportive care.
- How do the results of IELSG37 apply to someone like me?Why: Trial populations differ from individual patients; ask how closely you match.
Add these to your appointment list, or take the full question set for this cancer.
Residual PET-positive disease after immunochemotherapy
Biopsy where feasible; involved-site radiotherapy to the mediastinum (30 to 36 Gy) for persistent uptake; salvage therapy for proven refractory disease.
IMRT and IGRT shape the radiation beam to the tumour's outline from multiple angles and check the patient's position with a scan before every session, so surrounding organs receive less dose. Fewer, larger doses are now standard in breast and prostate cancer, but a low-dose bath still spreads across normal tissue.
- Conformal dose, fewer side effects
- Hypofractionation saves visits
Radiation using protons, which stop inside the tumour instead of passing through, so tissue behind it gets no dose.
- No exit dose; lower integral dose
- Reduced second cancers in children
FDG PET is the standard PET scan. A radioactive sugar shows which tissues are burning glucose fast, which most cancers do.
- Universal availability
- Decades of validation
No trial record is attached to this row yet. The trials tab lists what is recruiting and the landmark trials for this cancer.
- Low-dose bath to normal tissue
- Motion management
- Cost
- Range uncertainty
- Limited randomised evidence in adults
- Non-specific: infection and inflammation are also hot
- Brain background
- Poor in indolent tumours
- Between IMRT / IGRT (modern external beam), Proton therapy and FDG PET, which do you recommend for me, and what about my case would make you choose differently?Why: Guidelines list several reasonable options; the choice turns on details of your tumour, your health and your priorities.
- What is each option trying to achieve: cure, long control, or relief of symptoms, and over what time?Why: The aim shapes how much side effect and disruption is worth accepting.
- What happens if I delay, or decline this step for now? Is the decision reversible?Why: Some decisions can wait for a second opinion or a trial slot; others cannot. Knowing which is part of the choice.
- Does your recommendation follow the current guideline (NCCN Guidelines: B-Cell Lymphomas), and if it departs from it, why?Why: Departures from guidelines are sometimes right for an individual; they should be explained.
- For my situation (residual pet-positive disease after immunochemotherapy), which of the standard options do you recommend and why?Why: Guideline options include: Biopsy where feasible; involved-site radiotherapy to the mediastinum (30 to 36 Gy) for persistent uptake; salvage therapy for proven refractory disease.
Add these to your appointment list, or take the full question set for this cancer.
Relapsed or refractory
Salvage chemotherapy then autologous stem cell transplant if chemosensitive; pembrolizumab (KEYNOTE-170) or nivolumab plus brentuximab vedotin; CD19 CAR-T (axicabtagene ciloleucel, lisocabtagene maraleucel) after two lines or as second line for early relapse.
Autologous stem cell transplant collects the patient's own blood-forming stem cells, gives melphalan or another chemotherapy at a dose that would otherwise destroy the marrow, then returns the cells to rebuild it. It is standard consolidation in myeloma and for relapsed lymphoma, though CAR-T has displaced it in early-relapsing large B-cell lymphoma.
- Permits dose intensity impossible otherwise
- Decades of outcome data
- Widely available
Pembrolizumab is a PD-1 blocking antibody approved in more than 40 settings, from melanoma and lung cancer to the first tumour-agnostic approval for mismatch-repair-deficient tumours in 2017, and before and after surgery in triple-negative breast cancer. A subcutaneous form arrived in 2025, and it is the backbone partner for ADCs and personalised neoantigen vaccines.
Nivolumab was the second PD-1 blocker and is often combined with ipilimumab. Long-term data show about half of advanced melanoma patients alive at 10 years on the combination.
The ADC that made the modern field credible (2011), for Hodgkin lymphoma and CD30+ lymphomas.
A CD19 CAR-T that cures about 40% of patients with large B-cell lymphoma who had failed everything, and beat transplant in second line.
Lisocabtagene maraleucel is the only CAR-T approved for chronic lymphocytic leukaemia, for patients whose disease has outrun both BTK and BCL-2 inhibitors.
A patient's T cells are removed, given a synthetic receptor that recognises the cancer, multiplied, and put back as a living drug.
- Single infusion, durable remissions
- MHC-independent recognition
- Tests PembrolizumabRelapsed or refractory primary mediastinal large B-cell lymphoma after autologous transplant, or ineligible for it after two or more lines: pembrolizumab monotherapy
Objective response rate 45%, complete response 13%, in 53 patients with relapsed or refractory disease; FDA accelerated approval June 2018.
- Treatment-related mortality ~1-2% (myeloma) to higher in children
- Infertility, second malignancies, prolonged cytopenias
- Being challenged by CAR-T and MRD-guided deferral
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Hypothyroidism (immune-mediated) · Pooled monotherapy data, >2,800 patients | 8% | - |
| Pneumonitis (immune-mediated) · Pooled monotherapy data, >2,800 patients | 3.4% | - |
| Colitis (immune-mediated) · Pooled monotherapy data, >2,800 patients | 1.7% | - |
| Hepatitis (immune-mediated) · Pooled monotherapy data, >2,800 patients | 0.7% | - |
- No pharmacokinetic interactions expected (antibody). See the irAE guide for toxicity management.
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Colitis with ipilimumab (1+3 mg/kg) · Monotherapy pooled unless stated | 25% | 14.4% |
| Hepatitis with ipilimumab · Monotherapy pooled unless stated | 15% | 13.4% |
| Colitis · Monotherapy pooled unless stated | 2.9% | 1.7% |
| Hepatitis · Monotherapy pooled unless stated | 1.8% | 1.5% |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Neutropenia · ECHELON-1, A+AVD arm | 91% | 82% |
| Febrile neutropenia · ECHELON-1, A+AVD arm | 19% | 19% |
| Peripheral sensory neuropathy · ECHELON-1, A+AVD arm | 65% | 10% |
| Vomiting · ECHELON-1, A+AVD arm | 33% | 3% |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Cytokine release syndrome · TRANSCEND CLL 004 | 83% | 9% |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
- Manufacturing time and cost (~$400k+)
- CRS, ICANS, cytopenias
- Solid-tumour antigen heterogeneity, trafficking, exhaustion
- Between Autologous stem cell transplant (high-dose therapy), Pembrolizumab, Nivolumab and the other options, which do you recommend for me, and what about my case would make you choose differently?Why: Guidelines list several reasonable options; the choice turns on details of your tumour, your health and your priorities.
- What is each option trying to achieve: cure, long control, or relief of symptoms, and over what time?Why: The aim shapes how much side effect and disruption is worth accepting.
- How closely do I match the people in KEYNOTE-170, and does that change what the results mean for me?Why: Trial populations are selected; age, fitness, prior treatment and biomarkers all affect how far results carry.
- Which side effects of Pembrolizumab or Nivolumab are most likely for me, which are reversible, and which would make us stop?Why: The recorded rates below come from labels and trials; your own risk depends on dose, other medicines and your health.
- What happens if I delay, or decline this step for now? Is the decision reversible?Why: Some decisions can wait for a second opinion or a trial slot; others cannot. Knowing which is part of the choice.
- Does your recommendation follow the current guideline (NCCN Guidelines: B-Cell Lymphomas), and if it departs from it, why?Why: Departures from guidelines are sometimes right for an individual; they should be explained.
- For my situation (relapsed or refractory), which of the standard options do you recommend and why?Why: Guideline options include: Salvage chemotherapy then autologous stem cell transplant if chemosensitive; pembrolizumab (KEYNOTE-170) or nivolumab plus brentuximab vedotin; CD19 CAR-T (axicabtagene ciloleucel, lisocabtagene maraleucel) after two lines or as second line for early relapse.
- Am I a candidate for Pembrolizumab, Nivolumab, Brentuximab vedotin or related drugs, and what side effects should I expect?Why: Knowing the expected toxicities helps you plan work, family, and supportive care.
- How do the results of KEYNOTE-170 apply to someone like me?Why: Trial populations differ from individual patients; ask how closely you match.
Add these to your appointment list, or take the full question set for this cancer.