The first 60 days: Advanced systemic mastocytosis (aggressive SM, SM with an associated haematological neoplasm, mast cell leukaemia)
Advanced systemic mastocytosis is the dangerous form of this rare blood cancer, in which KIT-mutant mast cells damage the marrow, liver, gut or bones, grow alongside a second blood cancer such as chronic myelomonocytic leukaemia, or flood the blood as mast cell leukaemia. The KIT-blocking tablets midostaurin and avapritinib have replaced older chemotherapy, and fit patients may have a transplant. Below, week by week, is what OnCo's record of Advanced systemic mastocytosis (aggressive SM, SM with an associated haematological neoplasm, mast cell leukaemia) says about the first two months: the order is typical, the timing is yours to ask about. Sections appear only where the record has something to say. Orientation, not medical advice.
What happens now
Staging tests establish exactly what and where the cancer is. Everything else follows from the answers.
Bone marrow biopsy and aspirate, KIT D816V allele burden, myeloid mutation panel, tryptase, imaging for organomegaly and bone lesions, MARS or IPSM score.
Ask which of these were tested and what the results were; see the report reader for what each value means.
These specialties appear in the standard of care for this cancer. In most centres they meet weekly as a tumour board to agree each plan; you can ask when yours was discussed and what was decided.
- PathologistNamed in the standard of care for: Diagnosis and risk assessment, Associated haematological neoplasm.
- RadiologistNamed in the standard of care for: Diagnosis and risk assessment.
- Medical oncologistNamed in the standard of care for: First line, Associated haematological neoplasm, Relapsed or intolerant, Fit patients, especially mast cell leukaemia or high-risk SM-AHN.
- Transplant and cell therapy teamNamed in the standard of care for: Fit patients, especially mast cell leukaemia or high-risk SM-AHN.
A second opinion from a centre that treats many similar cases is normal, not rude; the standard of care tells you what to compare it against.
Each row is a setting from the standard of care, in the order it usually arises. Not all will apply to you; your stage and biomarkers decide which do. The guideline grade, where recorded, says how strong the evidence is.
- 1.Fit patients, especially mast cell leukaemia or high-risk SM-AHNNCCN Guidelines: Systemic Mastocytosis
Allogeneic haematopoietic cell transplantation after response to a KIT inhibitor.
Avapritinib 200 mg daily when platelets are 50 x 10^9/L or more (EXPLORER, PATHFINDER, approved 2021); midostaurin as the alternative (approved 2017).
Treat the neoplasm on its own merits (azacitidine for CMML or MDS, intensive chemotherapy for AML) alongside or after KIT inhibition.
Switch between avapritinib and midostaurin; cladribine; interferon alfa; bezuclastinib in the Apex trial.
Generated from this cancer's standard of care, biomarkers and open problems. Take the group that matches where you are. To tick, add your own and print, open the one-page appointment sheet.
Newly diagnosed
- What is my exact diagnosis, stage, and grade, and which tests established them?Everything else follows from an accurate stage and subtype.
- Which biomarkers have been tested on my tumour (for example C findings, Serum tryptase and KIT D816V allele burden, Mast cell percentage in marrow aspirate, SRSF2, ASXL1 and RUNX1 mutations; MARS and IPSM prognostic scores, Platelet count), and what were the results?These results decide eligibility for targeted therapy, immunotherapy, and trials.
- Which subtype is my cancer, and does that change the recommended treatment?Recognised subtypes for this cancer include Aggressive systemic mastocytosis, Systemic mastocytosis with an associated haematological neoplasm, Systemic mastocytosis with acute myeloid leukaemia.
- Is germline (inherited) genetic testing recommended for me or my family?Inherited variants can change treatment and matter for relatives.
Diagnosis and risk assessment
- For my situation (diagnosis and risk assessment), which of the standard options do you recommend and why?Guideline options include: Bone marrow biopsy and aspirate, KIT D816V allele burden, myeloid mutation panel, tryptase, imaging for organomegaly and bone lesions, MARS or IPSM score.
First line
- For my situation (first line), which of the standard options do you recommend and why?Guideline options include: Avapritinib 200 mg daily when platelets are 50 x 10^9/L or more (EXPLORER, PATHFINDER, approved 2021); midostaurin as the alternative (approved 2017).
- Am I a candidate for Avapritinib, Midostaurin, and what side effects should I expect?Knowing the expected toxicities helps you plan work, family, and supportive care.
Associated haematological neoplasm
- For my situation (associated haematological neoplasm), which of the standard options do you recommend and why?Guideline options include: Treat the neoplasm on its own merits (azacitidine for CMML or MDS, intensive chemotherapy for AML) alongside or after KIT inhibition.
- Am I a candidate for Azacitidine, Midostaurin, and what side effects should I expect?Knowing the expected toxicities helps you plan work, family, and supportive care.
Relapsed or intolerant
- For my situation (relapsed or intolerant), which of the standard options do you recommend and why?Guideline options include: Switch between avapritinib and midostaurin; cladribine; interferon alfa; bezuclastinib in the Apex trial.
- Am I a candidate for Cladribine, Interferon alfa-2a/2b, Bezuclastinib, and what side effects should I expect?Knowing the expected toxicities helps you plan work, family, and supportive care.
- How do the results of (Apex) Bezuclastinib in Patients With Advanced Systemic Mastocytosis apply to someone like me?Trial populations differ from individual patients; ask how closely you match.
Fit patients, especially mast cell leukaemia or high-risk SM-AHN
- For my situation (fit patients, especially mast cell leukaemia or high-risk sm-ahn), which of the standard options do you recommend and why?Guideline options include: Allogeneic haematopoietic cell transplantation after response to a KIT inhibitor.
Any stage
- Are there clinical trials I could join, for example of Avapritinib, Bezuclastinib, (Apex) Bezuclastinib in Patients With Advanced Systemic Mastocytosis, Allogeneic stem cell transplantation?Trials are how the next standard of care is set; asking early keeps options open.
- Would a second opinion at a high-volume centre change anything, and can you help arrange it?Rare or high-stakes decisions benefit from a centre that treats many similar patients.
- What supportive care (symptom control, nutrition, exercise, mental health, financial help) is available from the start?Supportive care improves quality of life and helps patients complete treatment.
- I read that “The associated myeloid neoplasm, not the mast cells, now causes most deaths in SM-AHN”. How does that affect my plan?Open problems are where trials and second opinions matter most.
- I read that “Whether KIT inhibitors improve survival has not been shown in a randomised trial”. How does that affect my plan?Open problems are where trials and second opinions matter most.
Trials open now for this cancer in OnCo, largest phase first. Joining a trial is a decision like any other: ask what the comparison arm is, whether a placebo is used, and what happens if you leave. The cancer page searches ClinicalTrials.gov live for more.
Much of what helps in the first weeks is free if you know to ask: testing, helplines, rides and lodging, second opinions, trial travel.
- Advanced systemic mastocytosis (aggressive SM, SM with an associated haematological neoplasm, mast cell leukaemia): the full pageAdvanced systemic mastocytosis is the dangerous form of this rare blood cancer, in which KIT-mutant mast cells damage the marrow, liver, gut or bones, grow alongside a second blood cancer such as chronic myelomonocytic leukaemia, or flood the blood as mast cell leukaemia. The KIT-blocking tablets midostaurin and avapritinib have replaced older chemotherapy, and fit patients may have a transplant.
- One-page appointment sheetYour questions, the words you may hear, what to bring, and space for the answers. Print it.
- Treatment sequencingWhich treatment tends to follow which, line by line.
- NavigatorStandard of care for your stage, what you have tried, and trials near you.
- Molecular response (MMR, MR4, treatment-free remission): In chronic myeloid leukaemia, how far the leukaemia gene signal in the blood has fallen, measured in logs: a 1,000-fold drop is a major molecular response, a 10,000-fold drop (MR4) is 'deep'.
- Cytopenias and myelosuppression: The umbrella term for low blood counts of any kind (white cells, red cells, platelets) when treatment suppresses the bone marrow.
- Driver mutation: One of the few mutations in a tumour that actually causes it to grow.
Every term links to the glossary.