The first 60 days: Small intestine cancer (small bowel adenocarcinoma)
Cancers of the small intestine are rare and often found late because the small bowel is hard to see and symptoms are vague. Surgery cures early disease, chemotherapy borrowed from bowel cancer helps after surgery and in advanced disease, and a large minority of tumours have a repair defect that makes them respond well to immunotherapy. Below, week by week, is what OnCo's record of Small intestine cancer (small bowel adenocarcinoma) 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.
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.
- SurgeonNamed in the standard of care for: Localised.
- Medical oncologistNamed in the standard of care for: Adjuvant (stage III; selected stage II), Advanced, MSI-high / dMMR, Advanced, MSS.
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.
Segmental resection with en bloc lymphadenectomy; pancreatoduodenectomy for duodenal tumours not amenable to segmental resection.
- 2.Adjuvant (stage III; selected stage II)NCCN category Category 2A, NCCN Guidelines: Small Bowel Adenocarcinoma; ASCO guideline 2024
Fluoropyrimidine with oxaliplatin (CAPOX or FOLFOX) for six months, extrapolated from colon cancer; BALLAD is the randomised test.
- 3.Advanced, MSI-high / dMMRNCCN category Category 2A (preferred), NCCN Guidelines: Small Bowel Adenocarcinoma
Pembrolizumab first line (tumour-agnostic approval; ZEBRA and KEYNOTE-158 cohorts).
CAPOX or FOLFOX first line; taxane- or irinotecan-based second line; HER2-directed therapy in trials; clinical trial enrolment encouraged.
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 MSI / mismatch repairstatus, HER2 amplification or ERBB2 mutation, KRAS, BRAF, TP53, Germline testing where Lynch, FAP or Peutz-Jeghers is suspected, CEA and CA 19-9 for monitoring), 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 Duodenal adenocarcinoma, Jejunal adenocarcinoma, Ileal adenocarcinoma.
- Is germline (inherited) genetic testing recommended for me or my family?Inherited variants can change treatment and matter for relatives.
Localised
- For my situation (localised), which of the standard options do you recommend and why?Guideline options include: Segmental resection with en bloc lymphadenectomy; pancreatoduodenectomy for duodenal tumours not amenable to segmental resection.
Adjuvant (stage III; selected stage II)
- For my situation (adjuvant (stage iii; selected stage ii)), which of the standard options do you recommend and why?Guideline options include: Fluoropyrimidine with oxaliplatin (CAPOX or FOLFOX) for six months, extrapolated from colon cancer; BALLAD is the randomised test.
- Am I a candidate for CAPOX (capecitabine, oxaliplatin), FOLFOX (5-FU, leucovorin, oxaliplatin), and what side effects should I expect?Knowing the expected toxicities helps you plan work, family, and supportive care.
Advanced, MSI-high / dMMR
- For my situation (advanced, msi-high / dmmr), which of the standard options do you recommend and why?Guideline options include: Pembrolizumab first line (tumour-agnostic approval; ZEBRA and KEYNOTE-158 cohorts).
- Am I a candidate for Pembrolizumab, and what side effects should I expect?Knowing the expected toxicities helps you plan work, family, and supportive care.
Advanced, MSS
- For my situation (advanced, mss), which of the standard options do you recommend and why?Guideline options include: CAPOX or FOLFOX first line; taxane- or irinotecan-based second line; HER2-directed therapy in trials; clinical trial enrolment encouraged.
- Am I a candidate for CAPOX (capecitabine, oxaliplatin), FOLFOX (5-FU, leucovorin, oxaliplatin), FOLFIRI (5-FU, leucovorin, irinotecan) 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 Pembrolizumab, Trastuzumab deruxtecan, Signatera?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 “Adjuvant chemotherapy benefit is unproven; BALLAD is the randomised answer”. How does that affect my plan?Open problems are where trials and second opinions matter most.
- I read that “Second-line therapy for MSS disease is weak; HER2 antibody-drug conjugates and trials in rare GI tumours are the route”. 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.
- Small intestine cancer (small bowel adenocarcinoma): the full pageCancers of the small intestine are rare and often found late because the small bowel is hard to see and symptoms are vague. Surgery cures early disease, chemotherapy borrowed from bowel cancer helps after surgery and in advanced disease, and a large minority of tumours have a repair defect that makes them respond well to immunotherapy.
- 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.
- Lynch syndrome: Lynch syndrome is the most common inherited cancer syndrome: a faulty mismatch-repair gene raises lifetime bowel cancer risk to 40-80% and also endometrial and other cancers.
- Lymphadenectomy (lymph node dissection): Surgically removing the lymph nodes that drain a tumour, both to stage the cancer and to clear any spread.
- Whipple procedure (pancreaticoduodenectomy): The big operation for cancers of the head of the pancreas: the surgeon removes the pancreatic head, the duodenum, the gallbladder and part of the bile duct, then reconnects everything.
- Microsatellite instability (MSI-H) / mismatch repair deficiency (dMMR): Microsatellite instability is the mark of a broken DNA spell-checker (loss of MLH1, MSH2, MSH6 or PMS2) that leaves thousands of mutations, so the tumour displays abnormal proteins that T cells can recognise.
- Endoscopy (EGD, EUS, ERCP): Looking inside a hollow organ with a camera on a flexible tube, taking biopsies and sometimes treating on the spot.
- Hereditary cancer syndromes: About 5-10% of cancers arise from an inherited gene fault.
Every term links to the glossary.