The improvement of health literacy in general and the information of individual patient is a major concern of the German national cancer plan and similar initiatives in other western countries. The aim of our study was to assess the readability and understandability of information booklets for cancer patients available at German Web sites. A support vector machine (SVM) was used to discriminate between laymen- and expert-centric patient information booklets about nine most common tumor types. All booklets had to be available for free at the Internet. A total of 52 different patient booklets were downloaded and assessed. Overall, the assessment of all booklets showed that an understandability level L of 4.6 and therefore increased medical background knowledge is required to understand a random text selected from the sample. The assessed information booklets on cancer show very limited suitability for laymen. We were able to demonstrate that a medical background is necessary to understand the examined booklets. The current study highlights the need to create information material adjusted to the needs of laymen. Assessing understandability before publication, especially for laymen with low health literacy, could ensure the suitability and thus quality of the information material.
Keywords: Evidence-based health information; Health literacy; Oncology; Patient information booklets; Readability; Understandability.