Colorectal cancer screening

Why screen?

About 5,000 new cases of colorectal cancer are diagnosed in Denmark each year, and around 2,000 people die from the disease annually. Risk rises with age and is higher in men than women. Finding cancer early markedly improves the chance of cure and often allows for less invasive treatment.

The Danish Health Authority recommends screening, but the decision is yours. You can decline the invitation or opt out of the programme at any time.

How bowel cancer develops

Cancer in the colon or rectum starts when cells in the bowel lining grow as small outgrowths called polyps. Most polyps are benign, but some slowly turn into cancer over several years. Risk is increased by age, smoking, heavy alcohol use, a low-fibre diet rich in red meat, and inherited forms of bowel cancer. Physical activity and whole-grain foods lower the risk. Bowel cancer can still occur in people without known risk factors.

Who is invited?

All residents aged 50 to 74 are automatically sent a screening invitation every two years. You receive the letter and a stool sample kit by post.

How the stool test works

Screening uses an immunochemical stool test (FIT) that looks for invisible blood in the stool. You take the sample at home following the enclosed instructions and return it to your regional screening unit in the prepaid envelope. The result usually arrives in e-Boks within 14 days.

What happens after a positive test?

If the test shows signs of blood, you are offered a follow-up endoscopic examination of the colon and rectum ([colonoscopy) within 14 days of the test being analysed. Signs of blood do not necessarily mean cancer – they can also be caused by haemorrhoids, anal fissures or polyps – but they always need further investigation.

Three possible colonoscopy results

• The bowel is normal. Risk of bowel cancer in the coming years is very low. You are offered the next screening test in 8 years.
• Polyps are found. They are usually removed during the same procedure and sent for microscopy. Further follow-up depends on the result.
• Cancer is found. You are referred immediately to treatment in a cancer fast-track pathway.

Treatment of bowel cancer

Cancer of the colon and rectum is most often treated surgically. The diseased section of bowel is removed, and in some cases chemotherapy or radiotherapy is added to reduce the risk of recurrence. The earlier the cancer is found, the less invasive the treatment can be. Read more about [symptoms and work-up.

Benefits of taking part

Better survival: early detection means lower risk of spread and a higher chance of cure.

Less invasive treatment: cancers and pre-cancers caught early can often be removed with smaller operations and without heavy medical follow-up.

Drawbacks and caveats

False alarm: blood in the test may come from harmless causes like fissures or haemorrhoids, but still triggers worry and further work-up.

False reassurance: a negative test is not a guarantee. If you develop symptoms – change in bowel habit, blood or mucus in the stool, abdominal pain, unexplained fatigue or weight loss – contact your GP, even if you have just been screened.

Discomfort: bowel cleansing and colonoscopy can feel uncomfortable. We offer sedation and pain relief as needed.

Overtreatment: some polyps removed at colonoscopy would never have become cancer.

Symptoms you should always act on

• Change in bowel habit lasting more than four weeks.
• Blood or mucus in the stool.
• Unexplained weight loss or fatigue.
• Persistent abdominal pain or a feeling that the bowel does not empty properly.

How the clinic can help

With a GP referral we offer colonoscopy as follow-up to a positive FIT test or for symptoms suggesting bowel disease. For suspected cancer we accept referrals in the fast-track pathway with a 7–10 working-day waiting time. See also [blood in the stool, polyp removal and colonoscopy.

Sources

This page is based on the Danish Health Authority's description of the national screening programme for cancer of the colon and rectum (Vidensbase, Forebyggelse: Screening for tarmkræft) and the 2023 patient leaflet *Tilbud om screening for kræft i tyk- og endetarm*.