Introduction
Screening and early detection examinations play an important role in many cancers, including colorectal cancer. As cancer cells often develop from benign progenitor cells, preventive examinations are very important after a certain age. These screenings can then detect and remove such cancer precursors before they transform into malignant cancer cells. There are various preventive and early detection measures for colorectal cancer, which are recommended from a certain age and are covered financially by health insurance companies.
These tests for colorectal cancer are available
Colonoscopy Digital-rectal examination (palpation of the lower rectum with the finger by the attending physician) Test for hidden (occult) blood in the stool M2-PK stool test Genetic test (to exclude HNPCC (hereditary non-polyposis colorectal cancer or lynch syndrome) and familial adenomatous polyposis (FAP))
- Colonoscopy (colonoscopy)
- Digital-rectal examination (palpation of the lower rectum with the finger by the treating physician)
- Test for hidden (occult) blood in stool
- M2-PK chair test
- Genetic test (to exclude HNPCC (hereditary non-polyposis colorectal carcinoma or lynch syndrome) and familial adenomatous polyposis (FAP)
Test for hidden blood in stool
In colorectal cancer, tumor cells grow in the area of the colon or rectum mucosa. These can cause small bleedings by growing into small blood vessels or from the patient’s own blood vessels. The blood enters the intestine and is excreted with the stool.
Usually these bleedings are so small that the blood in the stool cannot be seen with the naked eye. Therefore, there are tests that can detect this invisible, i.e. hidden or occult, blood in the stool. Until the beginning of 2017, the guaiac test, often referred to as the haemoccult test after the product name, was the standard method for detecting occult blood in stool.
In this test, a small sample of stool is applied to a card, the doctor then drips a special solution onto the card and if there is blood in the stool, the card changes colour. This is a chemical stool test, as the blood in the stool is detected by a chemical reaction. Since 2017 an immunological test procedure has replaced this chemical test.
It is called the iFOBT test. Here too, the patient gives a small stool sample and this is filled by the patient into a tube provided for this purpose, which he receives from his family doctor. The tube is then returned to the family doctor who sends it to a specialized laboratory.
The iFOBT uses antibodies that bind specifically to the red blood pigment (haemoglobin) to detect hidden blood in the stool. The immunological test has the advantage, among other things, that no false results are obtained if the patients have eaten certain foods shortly before the stool sample was given. In addition, the iFOBT test probably has a higher sensitivity (test detects sick people) and specificity (test does not falsely identify healthy people as sick) than the haemoccult test. The performance of the iFOBT is covered by health insurance companies every 2 years from the age of 50.
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