An interactive activity designed for use on an iPad, this program estimates the risk of recurrence in gastrointestinal stromal tumor (GIST)—a GI cancer—using various assessment methodologies. The application features 4 hypothetical GIST patients and allows you to select input for key tumor-related prognostic factors. The recurrence risk is then calculated utilizing 3 risk assessment tools, which were developed in conjunction with government institutes and major cancer organizations. It is intended as an educational exercise for use by oncologists and other healthcare professionals who are involved in the evaluation of patients after resection of a primary GIST. Information is presented for educational purposes only. Results not intended for use in treatment decisions. This easy-to-use application underscores not only the importance of assessing the risk of recurrence, but also how the estimated risk is influenced by various prognostic factors, as well as the selected assessment approach.