Primary CNS lymphoma: why R-CHOP fails, and what is given instead
A diffuse large B-cell lymphoma confined to the brain, spinal cord, eyes or meninges. The drugs that cure it elsewhere do not reach it: cyclophosphamide, doxorubicin and vincristine cross the blood-brain barrier poorly, so R-CHOP produces responses in the body and not in the brain, and trials of it in this disease were abandoned decades ago. Surgery has no therapeutic role beyond biopsy, and debulking does not help. Corticosteroids shrink the tumour dramatically and dissolve the diagnostic material with it, so steroids are withheld until the biopsy is taken wherever the patient is stable enough to wait. Induction is built around high-dose methotrexate at 3 to 3.5 g per square metre or more, given with leucovorin rescue and urinary alkalinisation, every two to three weeks. MATRix adds cytarabine, thiotepa and rituximab: in the first randomisation of IELSG32 the complete remission rate was 49 per cent with MATRix against 23 per cent with methotrexate and cytarabine alone and 30 per cent with methotrexate, cytarabine and rituximab. Six per cent of patients died of toxicity, so it is for patients fit enough to take it. The contribution of rituximab itself is contested: HOVON 105 randomised it into a methotrexate-based regimen and did not show the benefit that IELSG32's arm B against arm A comparison suggested.
The 1948 antifolate that produced the first chemotherapy remissions in childhood leukaemia and the first cure of a solid tumour; still essential in ALL, lymphoma, osteosarcoma and CNS lymphoma.
Cytarabine is the core chemotherapy for acute myeloid leukaemia, given with an anthracycline as the classic 7+3 induction and at high doses for consolidation; it is also injected into the spinal fluid to treat or prevent leukaemia in the brain.
Thiotepa is an old chemotherapy with a modern job: at high doses it prepares patients for stem cell transplants, and it is still instilled into the bladder or body cavities for superficial bladder cancer and malignant effusions.
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.
No trial record is attached to this row yet. The trials tab lists what is recruiting and the landmark trials for this cancer.
- High-dose methotrexate requires normal renal function, hydration, urine alkalinisation and leucovorin rescue with level monitoring.
| 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.
- Between Methotrexate, Cytarabine, Thiotepa 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.
- 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 Central Nervous System Cancers; ESMO/EANO; IELSG32, HOVON 105), and if it departs from it, why?Why: Departures from guidelines are sometimes right for an individual; they should be explained.
- For my situation (primary cns lymphoma: why r-chop fails, and what is given instead), which of the standard options do you recommend and why?Why: Guideline options include: A diffuse large B-cell lymphoma confined to the brain, spinal cord, eyes or meninges. The drugs that cure it elsewhere do not reach it: cyclophosphamide, doxorubicin and vincristine cross the blood-brain barrier poorly, so R-CHOP produces responses in the body and not in the brain, and trials of it in this disease were abandoned decades ago. Surgery has no therapeutic role beyond biopsy, and debulking does not help. Corticosteroids shrink the tumour dramatically and dissolve the diagnostic material with it, so steroids are withheld until the biopsy is taken wherever the patient is stable enough to wait. Induction is built around high-dose methotrexate at 3 to 3.5 g per square metre or more, given with leucovorin rescue and urinary alkalinisation, every two to three weeks. MATRix adds cytarabine, thiotepa and rituximab: in the first randomisation of IELSG32 the complete remission rate was 49 per cent with MATRix against 23 per cent with methotrexate and cytarabine alone and 30 per cent with methotrexate, cytarabine and rituximab. Six per cent of patients died of toxicity, so it is for patients fit enough to take it. The contribution of rituximab itself is contested: HOVON 105 randomised it into a methotrexate-based regimen and did not show the benefit that IELSG32's arm B against arm A comparison suggested.
- Am I a candidate for Methotrexate, Cytarabine, Thiotepa or related drugs, and what side effects should I expect?Why: Knowing the expected toxicities helps you plan work, family, and supportive care.
Add these to your appointment list, or take the full question set for this cancer.