Breast cancer and its treatment radiotherapy, have impact on woman's psychosocial and physical well-being causing disruption to quality of life. Because of the positive effects of knowledge on quality of life there is a challenge to develop effective education methods. Due to the growing use of internet among breast cancer patients the development should be focused on e-education. An e-education method, the e-Knowledge Test of radiotherapy with feedback for breast cancer patients (e-KTRT-BC) was planned and piloted. The content of it based on literature of breast cancer patients' knowledge needs of radiotherapy and structured through aspects of empowerment as a nursing intervention. The face validity study that was conducted via email revealed that the content of e-KTRC-BC was easy to use and understand. The e-KTRT-BC could be used as an e-education method to meet the breast cancer patients' knowledge needs. Evaluating the empowering effect of patient e-education with feedback is important for further development of e-education methods.