PROJECT SUMMARY Out-of-pocket (OOP) costs of cancer treatment are increasing as patients pay more of their health care costs in general, including higher insurance premiums and higher deductibles, co-insurance, and copayments. Cancer delivery has been described as a “system in crisis” as the financial burden of treatment costs affects nearly half of newly-diagnosed cancer patients. In this Phase I SBIR project, we will build and test Cancer Out-Of-Pocket Estimator (COOPE), a mobile/web system to assist with financial counseling for cancer patients initiating new cancer treatments. Following three specific aims, we will use a human-centered design (HCD) approach to develop a system for primary use by financial counselors working directly with patients. In Aim 1, we will conduct a requirements analysis with 20 potential system end users (financial counselors, cancer patients and their caregivers, oncologists, authorization representatives) to probe current perceptions of cancer cost discussions and the availability of estimated OOP cost data before initiation of patient treatment. In Aim 2, we will build a user-informed prototype of COOPE based on recommendations and specifications identified and outlined in Aim 1. The prototype will be reviewed by financial counselors and iterated to generate a version that will be used in subsequent field testing. In Aim 3, we will conduct a pilot study using mixed methods to study the use of COOPE in financial counseling at an urban, tertiary safety net hospital participating in the Oncology Care Model (OCM). We will examine usability and usefulness, usage patterns, perceived knowledge of cost information, patient satisfaction, accuracy of estimates, and financial distress. Measures of usability and usefulness (i.e., SEQ, UMUX-Lite) will be used to assess system acceptability and determine the potential of a Phase II project. Results of this Phase I SBIR project will go towards further development and validation of a pilot system to assess the effects of this system on financial planning and financial toxicity.