We present an EMR based approach to visualize all cancer relevant data in a so-called cancer diary at a single glance. System log and results of a user survey demonstrate increasing use and good usability of the cancer diary compared to traditional searches for relevant information in the entire patient EMR. We conclude that a cancer diary, aggregating data of diagnostic staging, tumor conference decisions and therapeutic actions may be a valuable EMR extension for hospitals focusing on cancer care e.g. within comprehensive cancer centers.