Colorectal cancer screening in persons under 50 years of age with a family history: large evidence gaps

In Germany, all persons over the age of 50 with statutory health insurance are currently offered colorectal cancer screening. On behalf of the Federal Joint Committee (G-BA), the Institute for Quality and Efficiency in Health Care (IQWiG) investigated whether screening should be started earlier in persons with a family history of colorectal cancer.

The result: An extensive research by IQWiG and a public commenting procedure identified large evidence gaps. There are neither targeted screening studies for persons under the age of 50 nor data that allow the findings on colorectal cancer screening in the general population over the age of 50 to be transferred to younger persons and thus enable indirect conclusions to be drawn.

If colorectal cancer screening in persons under 50 years of age with a family history of colorectal cancer should be applied more widely or introduced as a rule in Germany despite the sparse evidence, IQWiG recommends the accompanying generation of evidence, for example through comparisons with the situation in another country in which no such risk group screening is established. In its final report, IQWiG describes in detail how such an accompanying evaluation should be designed in order to provide meaningful evidence.

"Not all cancers are alike - so we must not pretend that the benefits of familial colorectal cancer screening are clear," emphasises Stefan Sauerland, Head of the Non-Drug Interventions department at IQWiG: "It is therefore by no means 'logical' that younger persons with an increased risk due to their family history also benefit from colorectal cancer screening. And it may well be that colorectal cancer screening offers no benefits to this group of persons. But this can only be investigated with sound accompanying studies - more research is urgently needed."

Too many research questions remain unanswered

Presently, organized colorectal cancer screening is generally offered in Germany from the age of 50 and not specifically for certain risk groups. For this reason, persons under the age of 50 with a family history of colorectal cancer are currently not entitled to take part in organized colorectal cancer screening programmes. In persons with a family history of colorectal cancer, at least one relative of the first or second degree (mother, brother, cousin, aunt, grandfather, etc.) has or had colorectal cancer without a known specific genetic cause. The risk of developing colorectal cancer is then twice to four times higher than in persons without a family history of colorectal cancer (see also the earlier IQWiG assessment S11-01.

What is known about the benefits and harms of colorectal cancer screening in persons under 50 years of age with a family history of colorectal cancer - to address this question, IQWiG searched for studies comparing screening and no screening in persons under 50 with a family history of colorectal cancer. In addition, the Institute also searched for studies investigating whether colorectal cancer develops similarly, progresses similarly, is diagnosed or can be treated similarly well in persons with or without a family history of the disease.

"However, despite the intensive research, there is a lack of direct evidence to answer the central question, and there is little information on the transferability of the benefits of colorectal cancer screening to persons under 50 with a family history of colorectal cancer. We have unsuccessfully searched all relevant data sources worldwide, but the data gaps are serious," summarizes Daniel Fleer, Division Head, Benefit Assessment of Non-Drug Interventions at IQWiG, "the data speak neither for nor against transferability”.

Process of report production

In November 2023, the G-BA commissioned IQWiG to assess colorectal cancer screening in persons with a family history. In August 2024, IQWiG published the preliminary results in the form of the preliminary report and interested parties were invited to submit comments. After completion of the commenting procedure, the preliminary report was revised and sent as a final report to the contracting agency, the Federal Joint Committee, in November 2013. The written comments submitted are published in a separate document at the same time as the final report.