Questions about colorectal cancer screening

How does the selection process work?

The target age group for screening is 56–74 years, and the screening interval is two years. These are based on research evidence. At this age, screening is most beneficial. Most of the colorectal cancers are found in people over 60 years of age.

However, in order to have sufficient health care resources, screening cannot be started at once for the entire target group. In 2022, nationwide screening for colorectal cancer will be introduced among men and women aged 60–68 years, and in 2023–2024, screening will cover those aged 60–70 years. Screening will be expanded by age group, and all 56–74-year-olds will be covered in 2031.

The effectiveness of the screening program is monitored in the Finnish Cancer Registry. If necessary, changes are made to the program.

Can I have a screening test privately?

Private testing is not recommended because the test is not the same as the screening. Screening is a chain of health-care activities that target a specific age group at regular intervals. In addition to the test, the screening process includes the necessary follow-up examinations and any further treatment and care.

In screening, the participants receive the test result directly for themselves without asking separately. The participants are also directed to follow-up and treatment whenever there is a need for them. After the right screening interval, they are invited to the screening again.

The quality and effectiveness of screening is continuously monitored and evaluated: if something does not work well, it is corrected.

You should not wait for a screening invitation if you have symptoms or worries about cancer. In such a situation, you should contact your doctor directly.

Why a stool blood test?

Colonoscopy is the best way to find the precursors of colon and rectal cancer. Why is then the FIT stool blood test the screening test used in Finland?

The use of a fecal blood test as a primary test in a population screening is due to its acceptability, low burden of harm, affordability, available colonoscopy resources, and evidence of efficacy.

Acceptability i.e. participation in FIT screening is high because it is easy: the test can be done conveniently at home, it only takes one sample, there are no food restrictions or other things to consider, and taking the test does not hurt.

As a test, FIT is virtually harmless. Colonoscopy, on the other hand, is an invasive procedure and always requires the bowel to be emptied in advance. Colonoscopy carries a risk of side effects (infection, bleeding, intestinal perforation).

­The use of a stool blood test as the first screening test allocates limited personnel and facility resources more appropriately. It is also an inexpensive screening method. Although the test must be repeated regularly, FIT sent every two years to 56-74 year olds is considerably less expensive than a single colonoscopy. In addition, there is no required population-level evidence of effectiveness from screening studies using colonoscopy as a primary test.

What happens after a positive result?

The majority of people who test positive will proceed to further examination, primarily colonoscopy. If further examination does not reveal a high risk of cancer, that is, the colon appears healthy and the cause of the bleeding is found to be benign (e.g., hemorrhoids), the individual will be next invited for screening after six years. The high-risk finding (precursor, cancer) will be treated and followed up according to standard practice in specialist care, and the next invitation to screening will come in ten years.

However, after a positive result, individuals under active endoscopic follow-up/control – most often due to inflammatory bowel disease (IBD: Crohn’s disease or ulcerative colitis) or bowel cancer – will not be referred for further investigation. This is the case also for individuals with the entire colon and rectum removed (proctocolectomy).

Patients with proctocolectomy and IBD will be excluded from the screening target population, meaning that they will no longer be invited for screening in the future. Those monitored due to diagnosed colorectal cancer will receive the next screening invitation ten years after their cancer diagnosis if they are still in the screening age group at that time.

When should you not participate? 

If you are in a control program including regular colonoscopies, for example after cancer treatment, for polyps, or for chronic inflammatory bowel disease, you do not need to participate in screening. You already get the follow-up you need. There is also no need to participate in screening if the entire colon and rectum have been removed (proctocolectomy).

Can I opt out of screening?

Participation in the screening is always voluntary. If you do not participate after receiving the invitation, the next invitation will be sent every two years until you are 74 years old. Screening invitations cannot be precluded in Finland.

Two reminders will be sent to non-participants. The purpose of the practice is to ensure that those entitled to screening also have the opportunity to participate in situations where there are problems with the mail, forgetting, drowning in a test device, etc. If you do not want reminders, you can notify the sender of the invitation (the screening laboratory; contact information in the invitation).