8 tests to detect bowel cancer

The most recommended exams and tests to detect bowel cancer are fecal occult blood testing, colonoscopy and rectosigmoidoscopy. However, in some cases virtual colonoscopy and upper digestive endoscopy may also be indicated.

These tests are usually indicated when there are signs and symptoms that may indicate bowel cancer, such as blood in the stool, constant pain in the abdomen, diarrhea, constipation or weight loss without an apparent cause. See more symptoms of bowel cancer.

If bowel cancer is suspected, it is important to consult a gastroenterologist, proctologist or general practitioner so that a detailed assessment can be carried out, the diagnosis confirmed and the most appropriate treatment initiated.

Main exams for the intestine

The main tests that help detect bowel cancer are:

1. Fecal occult blood test

The fecal occult blood test is done by analyzing a stool sample to identify the presence of blood even if it is not visible. This test may be positive in the case of bowel cancer, however, this result may also indicate polyps, hemorrhoids or diverticula, for example.

Therefore, this test does not confirm the diagnosis of bowel cancer, requiring more precise tests, such as colonoscopy, to confirm the cause of blood in the stool. Learn more about the fecal occult blood test.

2. Colonoscopy

Colonoscopy is a diagnostic test that can identify changes in the wall of the rectum and large intestine by viewing their interior with a small camera. Furthermore, during this exam it is still possible to remove changes in the intestine that may be indicative of cancer to be evaluated in the laboratory.

To take this exam, special preparation is necessary, which usually involves changes in diet and the use of laxatives in the days before taking it. Furthermore, colonoscopy is an exam that generally needs to be done under sedation. Find out how colonoscopy and preparation are performed.

3. Virtual colonoscopy

Virtual colonoscopy, also called computed tomography colonography, is an exam that creates three-dimensional images of the intestine using computed tomography to identify changes in its wall.

Normally, this exam does not require sedation or the use of contrast to be carried out and allows visualization of the rectum and large intestine. However, when changes are found that may indicate bowel cancer, a colonoscopy is usually necessary to complete the evaluation. Understand better what virtual colonoscopy is.

4. Retossigmoidoscopia

This exam uses a rigid or flexible tube with a small video camera at the end, which is introduced through the anus and is capable of observing the rectum and the final part of the large intestine, allowing the detection and removal of changes that may indicate cancer.

Despite being an exam capable of identifying bowel cancer, as it cannot visualize the entire organ, colonoscopy is normally indicated to complete the evaluation when changes are identified. See when rectosigmoidoscopy is indicated and how it is performed.

5. Intestinal transit examination

The intestinal transit exam consists of ingesting a contrast liquid, followed by X-ray images, to evaluate the shape and function of organs such as the esophagus, stomach and small intestine. This exam allows you to identify changes in the wall of the small intestine that may indicate cancer.

6. Bare enema

A barium enema is an exam that uses X-rays and a contrast liquid, which is inserted through the anus, to make images of the large intestine and rectum, and evaluate their shape and function.

Thus, it is possible to identify changes that may indicate bowel cancer, however, this test does not confirm the diagnosis. Check out what the barium enema is for and how it is done.

7. Upper digestive endoscopy

Upper digestive endoscopy, although less suitable for evaluating the intestine, is an exam that allows the visualization of the interior of organs in the digestive tract, such as the esophagus, stomach and the initial part of the small intestine, using a camera. Check out how digestive endoscopy is performed.

Thus, with this exam it is also possible to identify changes that may indicate bowel cancer.

8. Fecal DNA Test

The fecal DNA test is an exam capable of identifying genetic changes indicative of bowel cancer in the cells of the organ wall that are eliminated with feces.

This test does not require any preparation or changes to the diet, simply collecting a stool sample to be analyzed in the laboratory. However, whenever suspicious changes are identified, confirmation with another test, such as colonoscopy, is necessary.