Small Bowel Cancer: Diagnosis

Approved by the Cancer.Net Editorial Board, 08/2023

ON THIS PAGE: You will find a list of common tests, procedures, and scans that doctors use to find the cause of the medical problem. Use the menu to see other pages.

Doctors use many tests to find, or diagnose, cancer. They also do tests to learn if cancer has spread to another part of the body from where it started. If cancer has spread, it is called metastasis. Doctors may also do tests to learn which treatments could work best.

For most types of cancer, a biopsy is the only sure way for the doctor to know if an area of the body has cancer. In a biopsy, the doctor takes a small sample of tissue for testing in a laboratory. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis.

How small bowel adenocarcinoma is diagnosed

There are different tests used for diagnosing small bowel cancer. Not all tests described here will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:

  • The type of cancer suspected

  • Your signs and symptoms

  • Your age and general health

  • The results of earlier medical tests

In addition to a physical examination, the following tests may be used to diagnose small bowel cancer:

  • Blood tests. A test of the number of red blood cells in the blood can indicate whether the cancer is causing any bleeding. Tests for your liver and kidney function may also be performed. The results will determine whether either of those organs may be affected by the cancer and find out how healthy those organs are before having treatment for small bowel cancer.

  • X-ray. An x-ray creates a picture of the structures inside of the body using a small amount of radiation. It can help the doctor find a tumor. For small bowel cancer, x-rays may be taken of the entire gastrointestinal system, including the esophagus, stomach, small bowel, large intestine, and rectum. Sometimes, the person will drink a substance called barium, which outlines the esophagus, stomach, and small bowel on the x-ray and helps the doctor see tumors or other abnormal areas. This is called an upper gastrointestinal series with small bowel follow-through (UGI SBFT).

  • Biopsy. A biopsy is the only way to make a definite diagnosis, even if other tests can suggest that cancer is present. During a biopsy, a small amount of tissue is removed for examination under a microscope. A pathologist analyzes the sample(s). A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease.

  • Endoscopy. An endoscopy shows the inside of the gastrointestinal system using a thin, lighted, flexible tube called an endoscope. The person is sedated while the doctor inserts the endoscope through the mouth, down the esophagus, and into the stomach and small bowel. Sedation is giving medication to become more relaxed, calm, or sleepy. If abnormal areas are found, the doctor can remove a sample of tissue and check it for evidence of cancer. An endoscopy allows the doctor to see some, but not all, of the small bowel. Because of this, the doctor may recommend a videocapsule endoscopy (VCE). In this method, the patient swallows a small, pill-sized capsule that contains a tiny camera and light. Pictures are collected from the capsule as it travels through the patient’s gastrointestinal system. The capsule exits the body through normal bowel movement.

  • Colonoscopy. A colonoscopy is similar to the traditional endoscopy described above, except that the endoscope enters the body through the anus and rectum into the colon and lower part of the small bowel.

  • Computed tomography (CT or CAT) scan. A CT scan takes pictures of the inside of the body using x-rays taken from different angles. A computer combines these pictures into a detailed, 3-dimensional or 3D image that shows any abnormalities or tumors. A CT scan can be used to measure the tumor’s size. Sometimes, a special dye called a contrast medium is given before the scan to provide better detail on the image. This dye can be injected into a patient’s vein or given as a pill or liquid to swallow. A CT scan can check for the spread of cancer to the lungs, liver, and other organs.

  • Positron emission tomography (PET) or PET-CT scan. A PET scan creates pictures of organs and tissues inside the body. A PET scan is usually combined with a CT scan (see above), called a PET-CT scan. However, you may hear your doctor refer to this procedure just as a PET scan. A small amount of a radioactive sugar substance is injected into the patient’s body. This sugar substance is taken up by cells that use the most energy. Because cancer tends to use energy actively, it absorbs more of the radioactive substance. However, the amount of radiation in the substance is too low to be harmful. A scanner then detects this substance to produce images of the inside of the body.

  • Laparoscopy or laparotomy. In this procedure, a surgical incision is made in the abdomen to check for disease. Sometimes, tissue samples are taken and, often, surgery is performed at the same time to remove the tumor.

  • Biomarker testing of the tumor. Your doctor may recommend running laboratory tests on a tumor sample to identify specific genes, proteins, and other factors unique to the tumor. This may also be called molecular testing of the tumor. Results of these tests can help determine whether immunotherapy may be a treatment option for metastatic disease or if your tumor has a specific gene mutation that can be targeted with a targeted medication.

  • Liquid biopsy. A liquid biopsy is a blood test that measures circulating tumor DNA (ctDNA) that may be in your blood. Like biomarker testing of the tumor, results of a liquid biopsy can also help determine whether immunotherapy may be a treatment option. Liquid biopsies may be done in addition to biomarker testing of the tumor.

After diagnostic tests are done, your doctor will review the results with you. If the diagnosis is small bowel cancer, these results also help the doctor describe the cancer. This is called staging.

The next section in this guide is Stages and Grades. It explains the system doctors use to describe the extent of the disease. Use the menu to choose a different section to read in this guide.