Apr 15, 2026
Colorectal cancer screening: No informative evidence for adjusting age limits or colonoscopy frequency
Due to the lack of evidence, there is no apparent benefit for people without suspected cancer or without an increased risk of cancer. However, decision-analytical modelling by IQWiG shows options for G-BA decisions.
For people over 50, there is good evidence for recommending colorectal cancer screening – regardless of whether they choose colonoscopy or stool testing. However, due to a lack of good studies, no one currently knows with certainty whether people without an increased risk of colorectal cancer benefit from screening under the age of 50.
According to current regulations, people covered by statutory health insurance are entitled to colorectal cancer screening from the age of 50. This is because screening can detect precursors to cancer (polyps) in the colon or cancer itself, which can usually be treated very effectively. This can help avoid advanced stages of cancer and stressful treatment, and reduce cancer-related mortality. Both colonoscopy and a test for blood in the stool are available for the early detection of colorectal cancer (bowel cancer).
National and international organizations advocate colorectal cancer screening for people at average risk of developing colorectal cancer, although the preferred screening strategies differ. In the United States, expert societies recently reviewed their age recommendations for starting screening, proposing 45 years instead of 50. It has also been proposed to extend the 10-year minimum time interval between the first and the second colonoscopy, which is standard in Germany.
On behalf of the Federal Joint Committee (G-BA), the Institute for Quality and Efficiency in Health Care (IQWiG) has now reviewed whether conclusive evidence regarding the lower age limit, as well as the time interval and number of screening colonoscopies, is available.
The conclusion: There is no robust evidence to support reducing the current lower age limit from 50 to 45 years. The same applies to adjusting the time interval or frequency of colonoscopy compared with the current approach.
However, new evidence on these questions is not expected in the near future, as in order to obtain valid results several tens of thousands of people would need to be investigated over a very long observation period. IQWiG has therefore developed a decision-analytical model that provides additional information on different approaches to colorectal cancer screening.
Due to a lack of clinical evidence, we modelled different scenarios, including different approaches to earlier colorectal cancer screening. This makes it possible to identify key courses of action, with their respective advantages and disadvantages, and discuss them at the G-BA in order to make good health care decisions despite the lack of evidence.
Modelling of different approaches to colorectal cancer screening
IQWiG used modelling to estimate the possible effects of different screening approaches, e.g. a lower age limit or different time intervals between tests, for both screening tests. This was intended to help the G-BA compare possible options. Modelling is commonly used internationally to support decisions on screening programmes. After IQWiG had commissioned an external group of researchers with such modelling for the first time in 2022 for breast cancer screening, this was the first time modelling was developed and technically implemented by IQWiG itself.
As expected, IQWiG’s model showed that more tests can detect more cases of cancer and prevent more cancer deaths. However, the diagnostic effort and the burden on the individual who has to undergo all these tests increase exponentially. It is therefore necessary to weigh up the advantages and disadvantages, allowing for several options. One possibility would be to offer the current standard colorectal cancer screening over a wider age range and to adjust the time intervals between the examinations or the number of tests accordingly. However, it would also be conceivable to maintain the current screening programme.
Process of report production
On 19 December 2024, the G-BA commissioned IQWiG to review the lower age limit and frequency of screening colonoscopy in the colorectal cancer screening programme. IQWiG published the preliminary results in January 2026 and interested parties were invited to submit comments. After completion of the commenting procedure, the report was revised and sent to the commissioning agency in March. According to the standard process, the written comments submitted and the minutes of the scientific debate are published in a separate document at the same time as the final report.