Introduction
The term colorectal cancer screening refers to a special screening program for the early detection of malignant changes in the area of the intestine. Colon cancer screening is based on the individual risk of various groups of people developing colon cancer. The classification of a person into one of these specific risk groups determines both the exact timing and the frequency of the screening examination.
People with a family history of colorectal cancer are considered to be particularly at risk. Patients suffering from a chronic inflammatory bowel disease are also recommended to start a colorectal cancer screening program at an early stage. In principle, if there is an increased risk of developing colorectal cancer, colorectal cancer screening should be started at a younger age (25-30 years).
People without a significant risk should be enrolled in a colorectal cancer screening program at the age of 50 at the latest. This recommendation can be justified by the fact that the risk of colorectal cancer increases significantly after the age of 50. The costs of the colon cancer screening program for patients who have reached the age of 50 are partially covered by the statutory health insurance companies.
This means that both the preparation of an annual stool test and the so-called digital rectal examination are paid for as part of a colorectal cancer screening. From the age of 55 years, the performance of a colonoscopy is also covered. There are various examination methods available for colorectal cancer screening. In some patients, one of these methods is sufficient to rule out the presence of malignant changes in the area of the intestine. In many cases, however, the combination of several examination methods is useful.
What methods are there?
Among the most frequently used procedures in the course of a colorectal cancer screening are: a test for non-visible blood residues in the stool (occult blood test) palpation of the rectum (digital rectal examination) colonoscopy (colonoscopy) virtual colonoscopy (CT colonoscopy) In medical diagnostics, there are various methods of colorectal cancer screening available. They all have different areas of application, accuracy and subsequent therapeutic options. Very often, colonoscopy is used in screening.
It is paid for by the health insurance company from the age of 55 and is one of the most accurate diagnostic procedures. Here mucous membrane and wall changes of the colon can be detected and even treated at an early stage. Polyps, which are potential precursors of cancer, but also localised small cancer foci can be removed directly in a colonoscopy, also known as “colonoscopy”.
Their examination for malignant cells in the laboratory represents a further important preventive measure. Furthermore, the hemoccult test can be used as an uncomplicated procedure in colon cancer screening. Although this test does not provide a definitive diagnosis and its informative value is limited, positive results can provide important initial indications of malignant growth inside the intestine.
The test detects the smallest, invisible traces of blood that could indicate a tumour. The digital-rectal palpation test can also be performed cheaply and quickly, but is limited in its informative value. Only rough changes of the rectum and the prostate can be examined with this test.
Especially for young people who have a high family history of colorectal cancer, genetic diagnosis is an important preventive measure. Even at a young age, certain genes can be identified which increase the probability of bowel cancer. If the results are positive, other standards of screening must be applied, such as more frequent colonoscopies.
In order to diagnose colorectal cancer at an early stage, additional CT examinations, blood tests and the determination of so-called “tumor markers”, as well as capsular colonoscopies or numerous other modern procedures can be used. However, they have not yet become established in their efficiency in everyday clinical practice and have no place in routine screening. – a test for non-visible blood residues in the stool (occult blood test)
- Palpation of the rectum (digital rectal examination)
- Colonoscopy
- Virtual colonoscopy (CT colonoscopy)
- Special laboratory tests
Blood deposits on or in the stool are not always visible to the naked eye.
When the so-called occult blood test is carried out, hidden blood in the stool can also be detected and a first suspicion of the presence of intestinal cancer can be raised. Such blood deposits can be caused by intestinal polyps or intestinal tumours that provoke open spots in the area of the intestinal tube. In the course of bowel cancer screening, the occult blood test is carried out regularly once a year.
For patients who have reached the age of 50, the costs for this test are fully covered by both statutory and private health insurance companies. This method of colorectal cancer screening alone can identify 25 to 30 percent of polyps and tumors early. A positive occult blood test requires an immediate colonoscopy.
In this way the findings can be confirmed if necessary. The so-called “digital rectal examination” is a simple examination method that should be carried out regularly as part of colorectal cancer screening. In the course of this examination the doctor inspects the anal region and palpates the rectum with his finger.
In this way, changes in the area of the rectal outlet can be detected early. The digital rectal examination is also performed as part of prostate cancer screening. This method of screening for colorectal cancer can detect about half of the tumors located in the rectum.
However, digital rectal examination is unsuitable for colorectal cancer screening of higher tumors. This form of colorectal cancer screening is usually performed on an outpatient basis in specialized medical practices (gastroenterology, gastrointestinal physician) or in hospital. Before the actual colonoscopy, the intestinal tube must be completely emptied and cleaned by the patient.
Only in this way can the attending physician accurately assess the intestinal mucosa during colon cancer screening. For the purpose of emptying and cleaning the bowel, a laxative must be taken the day before the endoscopy. Afterwards, it is recommended to drink sufficient amounts of liquid (water or apple juice).
The gastrointestinal tract can then excrete as clear a liquid as possible until the start of the colonoscopy and thus rid itself of any remaining faecal deposits. The preparation of the colon cancer screening should be taken very seriously by the patient to be examined. A successful, meaningful colonoscopy can only be performed if the intestine is well cleaned.
Immediately before this form of colorectal cancer screening, the attending physician performs a digital rectal examination. Afterwards, the patient receives a light sedation if desired. During the actual colonoscopy, a flexible endoscope (a tube with integrated camera) is inserted through the anus into the intestine.
This device is advanced piece by piece, along the large intestine to the small intestine. During the advancement, air is also carefully introduced into the tube. The result of the inflow of air is the unfolding of the intestinal walls and a resulting improvement in visibility.
As soon as the endoscope has been advanced to the small intestine, the actual colorectal cancer screening begins. During the slow retraction of the endoscope, the intestinal mucosa can be viewed section by section. The camera head of the endoscope can be moved flexibly back and forth during the examination, thus providing an ideal overview of the mucosal conditions.
The duration of this form of colorectal cancer screening is about 20 minutes in most cases. In general, the entire procedure is largely painless. Only the pushing of the endoscope is perceived as unpleasant by some patients.
A further advantage of this type of colon cancer screening is the fact that possible mucous membrane changes (e.g. polyps) can be removed during the colonoscopy. It is therefore a screening examination in which precursors of colon carcinoma can be removed immediately. Following the examination, it is recommended that a resting phase be observed.
Patients who have been given sedatives during the colonoscopy will remain in the practice for about one to two hours. As soon as the patient’s circulation has stabilised and consciousness has been fully regained, he can be discharged under the supervision of a relative. As with most medical procedures, there are certain risks associated with performing a colonoscopy for colorectal cancer screening.
In general, however, one can assume that a colonoscopy performed by an experienced specialist is one of the safest and most gentle examination methods. In rare cases, the intestinal mucosa may be affected. The development of bleeding can also only be observed in a few patients.
Although perforation of the intestinal wall (so-called perforation) cannot be completely ruled out when taking tissue samples, it is one of the rare occurrences during colon cancer screening. Only for patients suffering from chronic inflammatory bowel disease is the risk of perforation increased. However, this is related to the already severe impairment of the intestinal walls.
Patients who undergo screening for colorectal cancer in twilight sleep could possibly develop allergic reactions to the medication administered. Virtual colonoscopy is one of the newer examination methods used in the course of colorectal cancer screening. This procedure enables a virtual colonoscopy without the need to enter the body with medical equipment.
During the virtual colonoscopy, computer tomography or magnetic resonance imaging of the abdomen is performed. With the help of a special 3D computer program, the acquired tomograms can be converted into a spatial image of the intestinal tube. The entire gastrointestinal tract can then be examined by a specialist on the monitor for any abnormalities.
The disadvantage of this examination method of colon cancer screening is the fact that especially small and/or flat intestinal polyps can be overlooked under certain circumstances. Furthermore, even if a polyp is discovered, it is not possible to remove it immediately. If the specialist sees an intestinal polyp on the screen, a standard colonoscopy must still be performed to remove the abnormality.
Patients who do not want to undergo a conventional colonoscopy can alternatively consider a colon cancer screening by means of capsule colonoscopy. This form of colorectal cancer screening is considered to have fewer complications than the usual examination methods. The capsule colonoscopy is particularly impressive because it is absolutely painless and non-invasive.
Since a large number of patients feel uncomfortable or even embarrassed during a normal colonoscopy, capsule colonoscopy offers completely new possibilities. Furthermore, no sedation and/or sedation is required during this examination method. At the beginning of the colonoscopy, the patient must swallow a capsule the size of a large, elongated tablet.
Due to its particularly smooth surface, the capsule is particularly easy to swallow. Over the course of several hours, the capsule passes through the gastrointestinal tract on its own and is then excreted in the stool. The capsule itself is equipped with an optical technique that images the inside of the intestinal tube at approximately 35 frames per second.
The images taken are also particularly high resolution and are transmitted to the outside during the intestinal passage. The recording of these images is carried out by a special receiving device which the patient must wear on his belt during the entire examination period. After the intestinal passage, the excreted capsule can easily be disposed of in the toilet.
Patients who decide against colonoscopy and opt for a capsule colonoscopy must be aware, however, that the reliability of this method is comparatively lower. In addition, no colon polyps can be removed even during a capsule colonoscopy. This means that if such polyps are found, an ordinary colonoscopy must still be performed.
Capsule colonoscopy in the course of colorectal cancer screening is not performed in every gastroenterological practice. In most cases, patients have to consult special specialists. The costs for a capsule colonoscopy are currently about 1000 Euros.
Both statutory and private health insurance companies only rarely cover these costs. There is no entitlement to reimbursement of costs. Patients who decide to undergo a capsule colonoscopy should contact their health insurance company directly to find out whether they will be covered.
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