Why is small bowel cancer found so late?

The small bowel is long and out of reach of standard upper endoscopy and colonoscopy, and the symptoms are vague — pain that comes and goes, anemia, fatigue. So with anemia of no obvious cause, the small bowel should also be examined with CT enterography or capsule endoscopy.

How do people live after part of the small bowel is removed?

Usually without restrictions. The small bowel is long, and removing a short segment does not affect digestion. After removal of the terminal ileum, vitamin B12 levels are monitored.

Is chemotherapy needed after surgery?

It depends on the stage: with lymph node involvement, adjuvant chemotherapy is usually recommended; in early stages the decision is based on risk factors. The medical oncologist chooses the regimen based on the pathology report.

Should my relatives be tested?

If tumor testing showed microsatellite instability or relatives had bowel or endometrial tumors at a young age, genetic counseling is recommended. If Lynch syndrome is confirmed, relatives are offered genetic testing, and carriers are offered regular screening.

I have already had surgery for obstruction. What next?

Obtain the pathology report and the operative report to find out whether the mesentery with lymph nodes was removed and whether the margins are clear. Next comes CT to assess spread and an MDT decision on chemotherapy or, less often, a repeat operation.

Small bowel cancer: diagnosis and resection with lymph nodes

Small bowel cancer is a rare tumor, and that is exactly why it is often diagnosed late: the small bowel is long, standard upper endoscopy and colonoscopy do not reach most of it, and the complaints are vague — intermittent pain, anemia, fatigue. The diagnosis is often made only during surgery for bowel obstruction. Yet when the tumor is found before it has spread, the main treatment is surgery: removal of the affected segment together with its mesentery and lymph nodes. After a limited resection the bowel usually works fully, because the remaining small bowel is long enough.

Kateryna Valikhnovska, MD, surgical oncologist, during a laparoscopic operation — The laparoscopic stage of an operation: the lights in the operating room are dimmed because the surgeon works from the camera image on the monitor.

Why small bowel cancer develops

Several types of tumors arise in the small bowel: adenocarcinoma, neuroendocrine tumors, gastrointestinal stromal tumors and lymphomas. This page is about adenocarcinoma, that is, cancer in the narrow sense. Other types are covered on separate pages on neuroendocrine tumors and GIST; tumors of the first part of the small bowel are covered on the duodenal tumors page.

The risk of small bowel adenocarcinoma is increased by Crohn’s disease involving the small bowel, celiac disease, and hereditary syndromes — Lynch syndrome, familial adenomatous polyposis, Peutz–Jeghers syndrome. If relatives had colon, endometrial or small bowel cancer at a young age, genetic counseling is advisable.

Are there symptoms

There are no specific symptoms. The most common are cramping abdominal pain that resolves on its own, bloating, nausea after meals, iron-deficiency anemia with no obvious cause, occult blood in the stool and weight loss. When the tumor narrows the lumen, episodes of partial obstruction appear: pain, vomiting, inability to pass gas.

Anemia whose source was not found on upper endoscopy and colonoscopy is a reason to examine the small bowel.

Examinations needed

CT or MR enterography — imaging with bowel contrast that shows the tumor, any narrowing, and the state of the mesentery and lymph nodes.
Capsule endoscopy — shows the lining of the entire small bowel; if a stricture is suspected, enterography or a patency capsule test is done first, so the capsule does not get stuck.
Balloon enteroscopy with biopsy — reaches the tumor, takes a biopsy and marks the site for the surgeon.
Contrast-enhanced CT of the chest, abdomen and pelvis — to assess spread.
Tumor markers CEA and CA 19-9.
Microsatellite instability testing (MSI/dMMR) — needed both for treatment choice and to detect Lynch syndrome.
Upper endoscopy and colonoscopy — to rule out other sources of bleeding and other tumors.

When surgery is possible

Surgery is recommended when there are no distant metastases and the tumor can be removed completely along with the lymph nodes. For resectable small bowel adenocarcinoma, chemotherapy before surgery is usually not given — surgery comes first, and further treatment is decided by the pathology of the removed tumor.

If the patient presents with obstruction, surgery is done urgently, with the same oncologic extent where possible: the mesentery and lymph nodes are removed with the tumor, not just the narrowed segment.

If surgery is not possible now

With distant metastases, chemotherapy becomes the basis of treatment; for tumors with microsatellite instability, immunotherapy may be effective. If the tumor causes obstruction or bleeding, a palliative procedure is performed — removal of the bowel segment or a bypass anastomosis, to relieve the obstruction.

When metastases shrink after treatment or are few, the MDT may consider removing the primary tumor and the metastases.

How the operation is performed

The segment of small bowel with the tumor is removed with a margin of healthy tissue on both sides, together with a wedge of mesentery containing the blood vessels and lymph nodes. Examining an adequate number of lymph nodes is important for accurate staging. The bowel ends are joined to restore continuity. The whole small bowel and the peritoneum are inspected during surgery.

If the tumor lies in the terminal ileum, next to the junction with the large bowel, the start of the large bowel is usually removed as well — ileocecal resection or right hemicolectomy, depending on the distance to the valve and lymphatic drainage. Duodenal tumors require a different operation, described on a separate page.

When the tumor’s location and the extent of resection allow, the operation is performed laparoscopically, through several small incisions.

A rare tumor is no reason for a rare operation. Removing the bowel segment with its mesentery and lymph nodes is the same standard as in colon cancer.

Kateryna Valikhnovska, MD, surgical oncologist

Recovery after surgery

Care follows the enhanced recovery after surgery (ERAS) protocol: early mobilization, early feeding, controlled pain relief. After removal of a short segment of small bowel, digestion usually recovers, and a strict diet is mostly not needed afterward.

After removal of the terminal ileum, absorption of vitamin B12 and bile acids may be impaired; B12 levels are then monitored and bowel habits adjusted if needed. With lymph node involvement, adjuvant chemotherapy is recommended; in stage II it is discussed based on risk factors; the medical oncologist decides on the regimen.

Follow-up

For the first years, CT and tumor markers are done regularly, every few months, and less often later; the doctor sets the schedule. In Lynch syndrome or polyposis, follow-up also includes regular colonoscopy and upper endoscopy. Warning signs — pain, anemia, weight loss — should be reported to the doctor without waiting for the scheduled check.

What to bring to the consultation

CT or MR enterography or CT discs with reports, capsule endoscopy recordings if performed;
the enteroscopy report and pathology report;
tissue blocks and slides — for review by another laboratory;
the operative report and discharge summary, if you have already had surgery for obstruction;
CEA and CA 19-9 results, complete blood count;
information about bowel diseases and cancer in the family.

If some materials are missing, that is no reason to postpone the consultation: some examinations can be done on site.

The consultation is free of charge. How it goes and how long it takes is described on the page “Oncologist Consultation”.