The first 60 days: Sinonasal undifferentiated carcinoma (SNUC) and SWI/SNF-deficient sinonasal carcinoma
Sinonasal undifferentiated carcinoma is a rare, fast-growing cancer of the nasal cavity and sinuses made of primitive cells with no clear line of differentiation, most carrying an IDH2 mutation. It presents as a large mass pressing on the eye or brain and is treated with chemotherapy first, then surgery or chemoradiotherapy depending on response; SMARCB1- or SMARCA4-deficient tumours are separate. Below, week by week, is what OnCo's record of Sinonasal undifferentiated carcinoma (SNUC) and SWI/SNF-deficient sinonasal carcinoma 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.
Biopsy with immunohistochemistry (cytokeratins, NUT, INI1, SMARCA4, neuroendocrine markers, EBER) and IDH2 testing; MRI and CT of the sinuses, skull base and neck; PET-CT.
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.
- RadiologistNamed in the standard of care for: Diagnosis.
- SurgeonNamed in the standard of care for: Non-responders to induction.
- Medical oncologistNamed in the standard of care for: Diagnosis, Locally advanced disease, first step, Responders to induction, Non-responders to induction and 1 more.
- Clinical oncologist (radiotherapy)Named in the standard of care for: Responders to induction, Non-responders to induction.
- Transplant and cell therapy teamNamed in the standard of care for: Locally advanced disease, first step.
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.Locally advanced disease, first stepNCCN Guidelines: Head and Neck Cancers (ethmoid and maxillary sinus tumours)
Induction chemotherapy with cisplatin and etoposide (or docetaxel-platinum) for two to three cycles.
- 2.Responders to inductionNCCN Guidelines: Head and Neck Cancers (ethmoid and maxillary sinus tumours)
Definitive chemoradiotherapy with concurrent cisplatin (intensity-modulated or proton), including elective neck irradiation.
- 3.Non-responders to inductionNCCN Guidelines: Head and Neck Cancers (ethmoid and maxillary sinus tumours)
Surgical resection where feasible followed by radiotherapy or chemoradiotherapy.
- 4.Metastatic or recurrent diseaseNCCN Guidelines: Head and Neck Cancers (ethmoid and maxillary sinus tumours)
Platinum-etoposide; PD-1 antibodies (pembrolizumab, nivolumab) on case series evidence; enasidenib for IDH2-mutant tumours in trials; EZH2 inhibitors for SWI/SNF-deficient carcinoma in trials.
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 IDH2 R172 mutation, SMARCB1and SMARCA4 immunohistochemistry, NUT immunohistochemistryand EBV, Response to induction chemotherapy on imaging, Neck node status), 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 IDH2-mutant sinonasal undifferentiated carcinoma, IDH2 wild-type sinonasal undifferentiated carcinoma, SMARCB1-deficient sinonasal carcinoma.
- Is germline (inherited) genetic testing recommended for me or my family?Inherited variants can change treatment and matter for relatives.
Diagnosis
- For my situation (diagnosis), which of the standard options do you recommend and why?Guideline options include: Biopsy with immunohistochemistry (cytokeratins, NUT, INI1, SMARCA4, neuroendocrine markers, EBER) and IDH2 testing; MRI and CT of the sinuses, skull base and neck; PET-CT.
Locally advanced disease, first step
- For my situation (locally advanced disease, first step), which of the standard options do you recommend and why?Guideline options include: Induction chemotherapy with cisplatin and etoposide (or docetaxel-platinum) for two to three cycles.
- Am I a candidate for Cisplatin, Etoposide, Platinum + etoposide (EP / CE), and what side effects should I expect?Knowing the expected toxicities helps you plan work, family, and supportive care.
Responders to induction
- For my situation (responders to induction), which of the standard options do you recommend and why?Guideline options include: Definitive chemoradiotherapy with concurrent cisplatin (intensity-modulated or proton), including elective neck irradiation.
- Am I a candidate for Cisplatin, and what side effects should I expect?Knowing the expected toxicities helps you plan work, family, and supportive care.
Non-responders to induction
- For my situation (non-responders to induction), which of the standard options do you recommend and why?Guideline options include: Surgical resection where feasible followed by radiotherapy or chemoradiotherapy.
Metastatic or recurrent disease
- For my situation (metastatic or recurrent disease), which of the standard options do you recommend and why?Guideline options include: Platinum-etoposide; PD-1 antibodies (pembrolizumab, nivolumab) on case series evidence; enasidenib for IDH2-mutant tumours in trials; EZH2 inhibitors for SWI/SNF-deficient carcinoma in trials.
- Am I a candidate for Platinum + etoposide (EP / CE), Pembrolizumab, Nivolumab or related drugs, and what side effects should I expect?Knowing the expected toxicities helps you plan work, family, and supportive care.
Any stage
- Are there clinical trials I could join, for example of Enasidenib, Proton therapy, Pembrolizumab?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 “No randomised trial exists and the induction-response strategy rests on one centre's series”. How does that affect my plan?Open problems are where trials and second opinions matter most.
- I read that “Enasidenib's activity in IDH2-mutant sinonasal carcinoma is unproven”. How does that affect my plan?Open problems are where trials and second opinions matter most.
Much of what helps in the first weeks is free if you know to ask: testing, helplines, rides and lodging, second opinions, trial travel.
- Sinonasal undifferentiated carcinoma (SNUC) and SWI/SNF-deficient sinonasal carcinoma: the full pageSinonasal undifferentiated carcinoma is a rare, fast-growing cancer of the nasal cavity and sinuses made of primitive cells with no clear line of differentiation, most carrying an IDH2 mutation. It presents as a large mass pressing on the eye or brain and is treated with chemotherapy first, then surgery or chemoradiotherapy depending on response; SMARCB1- or SMARCA4-deficient tumours are separate.
- 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.
- Head and neck subsites (oral cavity, oropharynx, larynx): Head and neck cancer is really several cancers named by exact location: mouth (oral cavity), back of the throat (oropharynx, where HPV cancers arise), voice box (larynx), lower throat (hypopharynx) and behind the nose (nasopharynx).
- Rare cancers: Rare cancers are those with fewer than about 6 new cases per 100,000 people per year.
- Chemoradiation (chemoradiotherapy, CRT): Radiotherapy given at the same time as chemotherapy, which sensitises the cancer to radiation.
Every term links to the glossary.