- 1. Stool examination
- 2. Colonoscopy
- 3. Computerized tomography virtual colonoscopy
- 4. Opaque enema
- 5. Retosigmoidoscopy
- 6. Fecal DNA testing
Tests to detect bowel cancer, such as colonoscopy, opaque enema or stool occult blood test, are routinely indicated for people over the age of 50, or earlier if indicated by the doctor, as in cases of people with a family history of the disease.
This screening is indicated even for people without any symptoms or risk for cancer, as the objective is to identify this disease, if it exists, in the early stages, with greater chances of cure.
However, they should also be done at any time if signs of this disease appear, such as bleeding in the stools, changes in the intestinal rhythm and weight loss, for example. Know the 8 main symptoms of intestinal cancer.
As there are several tests that investigate the presence of this type of cancer, the doctor should request the most suitable for each person, taking into account factors such as health status, the risk of cancer and the cost of the test. The main tests performed are:
1. Stool examination
The fecal occult blood test is the most widely used test to screen for bowel cancer, and should be done annually for people over the age of 50, as in addition to being practical and inexpensive, it is able to identify signs of blood in the intestines. feces, even if imperceptible to the eyes, which can happen in the early stages of cancer.
If blood is identified, the doctor will still need to order another more accurate test, such as colonoscopy, because in addition to cancer, bleeding can also be caused by polyps, hemorrhoids, diverticulosis or anal fissure, for example.
Currently, this test is done with a new technique, called an immunochemical test, which is more advantageous than the traditional method, since it detects smaller amounts of blood and does not suffer from interference from foods, such as beets.
2. Colonoscopy
Colonoscopy is a very complete exam and it is advantageous to identify intestinal changes, as it is able to visualize the entire large intestine and still biopsy or remove suspicious lesions, despite having disadvantages such as being expensive, needing intestinal preparation and sedation to be done.
This test is routinely indicated for people 50 years of age or older, every 10 years or whenever changes in fecal occult blood are identified.
It can also be requested by the doctor when symptoms appear that may indicate intestinal diseases, such as unjustified constipation or diarrhea, presence of blood and mucus in the stools, for example. Learn more about the colonoscopy exam.
3. Computerized tomography virtual colonoscopy
Virtual colonoscopy is an examination that creates three-dimensional images of the intestine using computed tomography, being able to observe both the external wall of the intestine and its interior.
It is a great test, as it can detect lesions such as cancer or polyps without the need for sedation, as in colonoscopy. However, despite its advantages, virtual colonoscopy is expensive, requires preparation of the intestine and whenever changes are detected, it may be necessary to complement the investigation with colonoscopy.
Learn more about how virtual colonoscopy is done, how to prepare and its benefits.
4. Opaque enema
Opaque enema also helps to identify changes in the intestine that can arise during cancer. To be done, it is necessary to insert a contrast liquid through the anus and then do an X-ray which, due to the contrast, is able to form images of the colon and rectum.
Currently, this test is not widely used to detect bowel cancer, because in addition to the complexity to be done, it can cause some discomfort or pain. In addition, it does not allow the taking of samples to perform the biopsy in the laboratory, and is often replaced by the colonoscopy exam.
Understand how this exam works and how to prepare.
5. Retosigmoidoscopy
To perform this examination, a rigid or flexible tube is used with a small video camera at the tip, which is introduced through the anus and is able to observe the rectum and the final part of the large intestine, allowing the detection and removal of suspicious lesions.
It is usually indicated for people over 50 years old, every 3 or 5 years in association with the fecal occult blood test. However, it is usually replaced by colonoscopy, which is a more complete examination.
6. Fecal DNA testing
It is a new test to screen for bowel cancer, also targeted at people over 50 or according to medical advice, as it is able to identify changes in the DNA of cells that indicate cancer or precancerous lesions, such as polyps.
Its advantages include not needing any preparation or changes in the diet, just collect a stool sample and send it to the laboratory. However, whenever suspicious changes are identified, confirmation with another test, such as colonoscopy, is required.
