What is it about ?
Colon cancer (or colorectal cancer) is a malignant tumor of the large intestine. It grows slowly, and usually starts from a polyp. The polyps are swellings of the lining of the intestine. Most often, they are mild and do not cause symptoms. This is precisely why it is important to detect possible polyps before symptoms appear. This is called a screening.
In Belgium, the screening for colorectal cancer is the subject of a national screening program. As part of this program, you are invited to get tested every 2 years.
Cause and risk factors
The cause of colorectal cancer is not yet fully understood. Several causes are undoubtedly responsible.
Factors that increase the risk of colorectal cancer include:
- age;
- The older you are, the higher the risk.
- a hereditary predisposition;
- Your father, mother, sisters or brothers have (had) the disease.
- a existing disease intestines, like the Crohn’s disease or the ulcerative colitis ;
- a poor lifestyle :
- you eat too much fat and red meat, and not enough fiber;
- smoking;
- excess weight;
- a lack of physical activity.
What is its frequency?
Each year, just over 8,000 Belgians learn that they have colorectal cancer. It is the third cancer in men (after Prostate cancer and the lung cancer) and second cancer in women (after breast cancer).
In about three quarters of cases, age is the only factor involved. The hereditary form is infrequent.
What tests are used to screen for colorectal cancer?
Stool analysis
The national screening program uses a stool test. This test detects invisible traces of blood in the stool. To do this, it is sufficient to provide a stool sample.
Endoscopy of the bowel (colonoscopy)
When the stool test gives a positive result or abnormal, it means there is blood in your stool. In this case, you must take additional exams. The doctor inspects the inside of your colon using a camera (colonoscopy) to detect any anomalies.
If your stool test gives a positive result, there is no point in repeating the test. You still need to have a colonoscopy.
Test results
- If the colonoscopy is normal after a positive stool test result, the next stool test should only be performed after 10 years.
- If the colonoscopy reveals anomalies, the doctor specializing in diseases of the stomach and intestines (gastroenterologist) will schedule a follow-up visit.
Who is screened?
All people aged 50 to 74whether or not they have risk factors, receive a letter every 2 years inviting them to have a stool test. The test is not compulsory.
People at risk
Screening begins earlier (from the age of 40) when there are cases of colorectal cancer in the family (father, mother, brother (s) and / or sister (s)).
People who are exposed to higher risk and / or who have a chronic bowel disease must pass a colonoscopy. They should therefore not start with the stool analysis. It will be decided in consultation with the gastroenterologist, how often they should have a colonoscopy in order to monitor their state of health.
Advantages and disadvantages of screening for colorectal cancer
Advantages
- Colorectal cancer grows very slowly. A doctor can detect and remove any polyps before cancer cells appear.
- Early detection of cancer or cancer risk helps to avoid complications or (heavier) treatment.
- The chances of complete recovery are also larger.
Disadvantages
The ideal test is one that always gives a positive result when a person has a condition and which always gives a negative result when they do not have that condition. Unfortunately, the ideal test does not exist. From time to time there are “false positive” or “false negative” results.
- A false positive indicates that the person is sick when they are not
- A false negative indicates that the person is not sick when they are.
Other disadvantages of screening include:
- the’anguish pending results;
- the’awaiting follow-up examination in the event of an abnormal screening test result;
- the complications possible follow-up examination (colonoscopy).