Tests to detect bowel cancer such as colonoscopy, opaque enema, or stool occult blood screening are routinely indicated for people over the age of 50, or earlier if indicated by the physician, as in cases of people with a family history of the disease.
This screening is indicated even for people without any cancer symptom or risk, since the objective is to identify this disease, if it exists, in the still early stages, with a greater chance of cure.
However, they should also be done at any time if signs of this disease arise, such as bleeding in the stool, changes in the bowel and slimming, 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 ask for the most appropriate one for each person, taking into account factors such as health status, cancer risk and the cost of the examination. The main tests performed are:
1. Stool examination
The fecal occult blood test is the most commonly used test to track bowel cancer, and it should be done annually for people over the age of 50 because it is practical and inexpensive to identify blood feces, even if imperceptible to the eyes, which can happen in the early stages of cancer.
If the blood is identified, the doctor will also need to ask for a more precise examination, such as a colonoscopy, because in addition to cancer, bleeding can also be caused by polyps, hemorrhoids, diverticulosis or anal fissures, 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 interference from foods such as beets.
2. Colonoscopy
Colonoscopy is a very thorough examination and it is advantageous to identify intestinal changes because it is able to visualize the entire large intestine and still biopsy or remove suspicious lesions, despite having disadvantages such as being expensive, requiring 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 the stool occult blood test are identified.
It can also be requested by the doctor when symptoms appear that may indicate intestinal diseases, such as unwarranted constipation or diarrhea, presence of blood and mucus in the stool, for example. Learn more about the colonoscopy exam.
3. Virtual colonoscopy by computed tomography
Virtual colonoscopy is an examination that creates three-dimensional imaging of the bowel using computed tomography, being able to observe both the external wall of the intestine and its interior.
It is a great exam, because it can detect lesions like cancer or polyps without the need to perform a sedation, as in colonoscopy. However, despite its advantages, virtual colonoscopy is expensive, needs 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 it, and its benefits.
4. Opaque Enema
The opaque enema also helps identify changes in the bowel that may arise during cancer. To do this, it is necessary to insert a contrast liquid through the anus and then make an X-ray which, due to the contrast, is capable of forming 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 withdrawal of samples to do the biopsy in laboratory, being often replaced by the examination of colonoscopy.
Understand how this exam works and how to prepare.
5. Retrosigmoidoscopy
To perform this test, a rigid or flexible tube is used with a small video camera at the tip, which is inserted through the anus and is able to observe the rectum and the end part of the large intestine, allowing the detection and removal of suspicious lesions.
It is usually indicated for people over 50, every 3 or 5 years in association with occult blood fecal screening. However, it is usually replaced by colonocopia, 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 guidance, 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 diet, simply collect a stool sample and send it to the laboratory. However, whenever suspicious changes are identified, confirmation with another examination, such as colonoscopy, is required.
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