Claro study

Project coordination

Prof. Dr. Karen Steindorf, Dr. Florian Herbolsheimer, Dr. Alexander Haussmann

Why is the CLARO study relevant?

A healthy lifestyle plays an essential role in the development of cancer. It is estimated that up to 40% of all cancers could be prevented by a healthy lifestyle. However, international studies show that many people are not aware of the connection between lifestyle factors and cancer risk. Consequently, primary cancer prevention begins by identifying and closing gaps in knowledge. For this, it is relevant that as many people as possible are able to recognize reliable sources of information and understand the presented information. This knowledge and the associated skills needed to acquire and apply the relevant knowledge are referred to as "cancer literacy".

How will be the CLARO study conducted?

A representative survey of about 800 participants in the Stuttgart area will record cancer literacy for the first time in Germany. This includes knowledge of cancer risk factors, attitudes towards cancer prevention and information search in connection with cancer. At the same time, the participants will be presented with various information materials in the form of texts and animations in different communication styles (formal or narrative).

What are the goals of the CLARO study?

The project will assess the current state of knowledge on cancer prevention in Germany and additionally develop strategies on how to better reach people with low cancer literacy in particular. In the process, information materials will be created to sustainably increase awareness of the ability to change one's own cancer risk. The information materials will then be made available to the general public and, among other things, will be included in the range of services offered by the emerging National Cancer Prevention Center in Heidelberg.

Who is involved in the CLARO study?

The German Cancer Research Center in cooperation with the Cancer Information Service, the National Cancer Prevention Center and the Hanover University of Music, Drama, and Media is conducting the CLARO study. The study is part of the Graduate College for Cancer Prevention, funded by the German Cancer Aid.

First Results from the CLARO Project Published

As part of the CLARO project, a population-based survey was conducted to investigate knowledge of cancer prevention in Germany. A total of 1,232 residents of Stuttgart participated in the survey.

The results show that many people correctly identify well-known cancer risk factors, such as smoking and sunburn. However, substantial knowledge gaps remain regarding other scientifically established risk factors, including infection with the human papillomavirus (HPV) and prolonged sitting. In addition, misconceptions about the causes of cancer are widespread. Among the misconceptions most frequently identified correctly was the belief that using a mobile phone or smartphone causes cancer: 53% of respondents correctly recognized this statement as false.

Most respondents reported using the internet or consulting healthcare professionals to obtain information about cancer prevention. By contrast, the German Cancer Information Service is used by only a small proportion of respondents. Nearly one in two participants reported feeling overwhelmed by the large amount of information available on cancer prevention.

The findings highlight the need for clear, evidence-based communication on cancer prevention. High-quality information can help close knowledge gaps, counter misinformation, and support people in making informed decisions about their health.

These findings underscore the importance of improving cancer prevention communication to better inform the public and strengthen cancer prevention efforts.

Publications

Cancer prevention in Germany: awareness, beliefs, and information-seeking behaviors in a population-based survey (2026): Illmann M, Steindorf K, Haussmann A, Herbolsheimer F. Front. Public Health, Vol. 14, https://doi.org/10.3389/fpubh.2026.1868556