Colonoscopy
A colonoscopy is a camera examination of the large intestine that finds and removes precancerous polyps before they can turn into colorectal cancer. Most people should have their first one at 45, then every 10 years if the result is normal.
German name: Darmspiegelung (Koloskopie) · Category: Cancer screening
Key facts
| From what age? | 45 (40 with a first-degree relative affected, or 10 years before their diagnosis age) |
|---|---|
| How often? | Every 10 years if normal; every 3–5 years if polyps were removed |
| How long does it take? | 20–40 minutes for the procedure, about half a day including preparation and recovery |
| What does it cost? | Covered by German statutory insurance from age 50 (men) and 55 (women); earlier or private screening typically costs €400–800. |
Who needs a colonoscopy?
Every adult from 45 onwards, and earlier for anyone with a family history of colorectal cancer or polyps, inflammatory bowel disease, or a known hereditary syndrome such as Lynch syndrome or FAP. Symptoms like rectal bleeding, unexplained anaemia or a persistent change in bowel habit are reasons to go now, at any age.
What happens during a colonoscopy?
You lie on your side and receive a short-acting sedative through a cannula, so most people sleep through the examination. A flexible endoscope is guided through the colon while air or CO2 gently expands it. The doctor inspects the mucosa, photographs anything suspicious and removes polyps in the same session with a wire loop or forceps. Removed tissue goes to a pathology lab. You rest for about an hour afterwards and cannot drive for the rest of the day.
How do you prepare for a colonoscopy?
Stop iron supplements about a week before and avoid seeds, nuts and high-fibre food for three days. The day before, keep to clear liquids and drink the bowel preparation solution as prescribed, usually in two portions – one in the evening, one early on the day of the exam. Keep drinking clear fluids until two hours before the appointment. Tell the practice about blood thinners, diabetes medication and any implanted device well in advance.
How do you read the result?
A normal result means no polyps were found and your next screening is due in 10 years. Hyperplastic or small adenomatous polyps that were fully removed usually mean a repeat in 5–10 years. Advanced adenomas, several polyps, or incomplete removal shorten the interval to 3 years. The pathology report matters more than the endoscopy photos: ask for the histology, the number and size of polyps, and the caecal intubation and bowel preparation quality – a poor preparation lowers detection and may justify an earlier repeat.
What does the evidence say?
Removing adenomatous polyps at colonoscopy reduced colorectal cancer mortality by 53% over long-term follow-up.
Zauber et al., New England Journal of Medicine (2012)The US Preventive Services Task Force recommends starting colorectal cancer screening at age 45 for average-risk adults.
U.S. Preventive Services Task Force, Colorectal Cancer: Screening (2021)Screening colonoscopy in a population-based trial reduced colorectal cancer incidence, with the largest benefit among those who actually attended.
Bretthauer et al., NordICC trial, New England Journal of Medicine (2022)