Dear colleague,

Welcome to this online study within the COMET T1 CRC project. In this study, you will be asked to optically diagnose 60 colorectal lesions based on a video of each lesion. The video contains footage of the lesion in High Definition White Light (HDWL) and Narrow Band Imaging (NBI). In all 60 cases, you will be asked the same five questions, aimed at the endoscopic recognition of colorectal carcinoma.

We will compare the optical diagnosis of all participants to the diagnosis of a computer-aided diagnosis system based on artificial intelligence. Your individual results will not be reported.

Participation in this study can give you insight into your own optical diagnosis and recognition of colorectal carcinoma. If you wish to receive feedback on your performance, please fill out your name and e-mail address on the next page.

Before the assessment of the 60 colorectal lesion starts, we ask you to fill out one page of background information regarding your endoscopy experience.

Participation in this study takes approximately 60 minutes. It is not possible to start your participation and continue at a later time. Please participate on a computer, laptop, or tablet, not on a mobile phone. It is possible to rewind and rewatch a video.

If you have questions regarding this study, please contact Ayla Thijssen, a.thijssen@maastrichtuniversity.nl, +3143 388 1844.

If you do not wish to participate, you can leave this page. By proceeding to the next page, you give your consent to use your response in our research.

Thank you very much for considering to participate in this study.

Kind regards,

On behalf of the Dutch T1 Colorectal Cancer Working Group and COMET T1 CRC study group,

Prof. dr. Erik Schoon, principal investigator

Ayla Thijssen, coordinating investigator

GROW Research Institute for Oncology and Reproduction, Maastricht University