As part of the CAWIP (Clinical Anatomy for Well-Informed Patients) project, a smartphone app for patient education and personal information in the home environment for patients with colorectal cancer will be developed and evaluated. The doctors will use the app to improve communication in conjunction with CT or MRI images that have been processed in a patient-oriented and patient-specific manner by illustrating conservative and/or surgical clinical treatment on the patient's body based on the anatomical correlations. By means of visualisation, the app is intended to help patients better assess the extent of the disease and the therapeutic approach as well as potential treatment risks. During the joint consultation, a photo is taken and with the app, the prepared individual CT scans of the organs can be projected onto the photographed body and corresponding anatomical/clinical explanations etc. can be called up, also with reference to the individual clinical picture. In addition, doctors can activate illustrative videos in the app that are still to be recorded as part of the project, which patients can then watch at home with their relatives.