Diagnosing intestinal cancer

This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science

This page was updated on May 20, 2022.


An accurate intestinal cancer diagnosis is the first step in developing a treatment plan for intestinal cancer. Your care team will use a variety of tests and tools designed for diagnosing intestinal cancer, evaluating the disease and developing your treatment plan. Throughout your treatment, the care team will use imaging and laboratory tests to track the size of your tumors and monitor your response to treatment.

Your doctor is likely to start by asking about your medical history, as well as the medical history of your close family members. Questions may involve any lifestyle and health habits, past illnesses and treatments.

Your doctor may also perform a physical exam, checking the abdomen to see whether it appears swollen or whether any sounds suggest there may be a blockage.

Armed with your personal and family medical history and the results of the physical exam, your doctor may order laboratory tests, imaging studies and other procedures (including a biopsy).

Common tools used for diagnosing intestinal cancer and staging the disease include:

Upper gastrointestinal series is a series of highlight X-rays of the esophagus, stomach and the upper portion of the small intestine. This procedure may require the patient to swallow barium that enhances the X-ray images. If your doctor finds abnormal cells during this procedure, the next step may be an endoscopic procedure or another diagnostic imaging test for intestinal cancer. This X-ray series is used less often than other imaging tests, because it’s not as easy to see some abnormal areas, and it’s not possible to take a biopsy at the same time.

Enteroclysis is a test for small intestine cancer and provides the care team with more detailed pictures of the small intestine than an upper GI test.

Barium enema is performed by inserting barium into the rectum, filling the colon. X-rays taken during the enema are enhanced by the barium and may enable your doctor to better detect polyps and other suspicious tissues that need to be examined more closely or removed in a colonoscopy.

CT scan is a procedure that may give doctors a more detailed image of the colon and intestines and help determine the stage of the cancer and whether the disease has spread.

A PET-CT scan is a combination of a positron emission tomography (PET) scan and a computed tomography (CT) scan used to look for cancer. During this scan, you’re injected with a radioactive sugar substance. Cancer uses more energy and absorbs more of the radioactive material more quickly. The doctor examines the scans looking for areas of quick uptake that could indicate intestinal cancer.

Endoscopic procedures

Endoscopic procedures allow doctors to examine the body from the inside. These procedures use an endoscope, an instrument that usually has a light attached and is inserted directly into a body cavity or organ. You’re given sedation for the procedure.

Your small intestine is about 20 feet in length. Different endoscopic procedures may be used to see all or part of the small intestine, including:

Esophagogastroduodenoscopy (EGD), or upper endoscopy: During this procedure, you’re given a local anesthetic and a mouthguard to protect your teeth and the endoscope. While lying on your left side, a scope with a camera is inserted in the esophagus and into the duodenum, or small intestine. Your doctor can see images of your esophagus, stomach and upper duodenum projected on a screen. Air is pushed through the scope, making it easier for your doctor to see. If an area needs to be biopsied, it may be done at this time. The procedure takes anywhere from 5 to 20 minutes.

Video capsule endoscopy (VCE): With an endoscopy, your doctor isn’t likely to be able to see all of the small bowel. As a result, your doctor may recommend a video capsule endoscopy. During this procedure, you will be asked to swallow a capsule that contains a tiny camera. As the capsule travels through the intestinal system, it projects photos on a computer screen. The capsule exits the body the next time you have a bowel movement.

Double-balloon endoscopy (DBE): Your doctor may order this test if the results of the video capsule endoscopy results raise questions or appear abnormal. During this procedure, also called a double-balloon enteroscopy, your doctor uses a specially designed endoscope to look deep into your small intestine. Two tubes make up the specialized tool (one has a camera and is located inside the other, which has a balloon at the end). By inflating and deflating the balloon, the doctor may push the camera farther within the small bowel for better visualization. Your doctor also may take samples of abnormal tissue for laboratory analysis.

Blood tests

If your doctor suspects you have intestinal cancer, blood tests may be ordered, including:

CBC (complete blood count): Cancer of the small intestine may cause intestinal bleeding. This test measures the levels of red blood cells, white blood cells and platelets. A low red blood cell count may suggest intestinal bleeding, which may also cause anemia.

Liver function tests (LFTs): Liver function tests measure levels of substances that the liver releases into your bloodstream. If the amount of these substances is higher or lower than normal, it may suggest that your liver has been affected by cancer.


Blood tests and imaging studies are used to detect suspected intestinal cancers. However, once a suspicious lesion is identified, it’s likely you may need a biopsy of the area to determine whether it’s malignant (cancerous). Your doctor removes a piece of tissue from the area where cancer is suspected and sends it to the pathology lab. There, technicians study it under a microscope, and a pathologist makes a determination.

Biopsy samples may be taken in different ways:

  • Endoscopy: A small piece of tissue is removed while the endoscope, a flexible lighted tube, is passed down your esophagus to see the inner lining of your gastrointestinal tract.
  • Image-guided biopsy: It may be possible for your doctor to use imaging such as a CT scan to guide a thin, hollow needle to the suspected tumor and grab a piece to send to the lab.
  • Surgery: If your doctor can’t reach the suspicious area with an endoscope, a surgical incision in the abdomen may be needed to biopsy a suspected tumor.

Some biopsies require regional or general anesthesia, while others are done under a local anesthetic.


Thanks to advances in minimally invasive procedures, laparotomy isn’t used as often these days. However, sometimes it’s necessary. A laparotomy requires making a large incision in the wall of the abdomen, so your doctor may see directly inside the abdominal cavity. This surgical procedure is performed under general anesthesia.

The reason for your laparotomy will determine how big an incision is necessary. Doctors may want to take samples of organs or tissues to send to the pathology lab to check for disease.

This procedure isn’t indicated for someone who may have extensive scar tissue in the abdomen, who can’t undergo general anesthesia, or who has widespread cancer.

Next topic: How is intestinal cancer treated?

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