Background: Informing patients with cancer about the possible implications of prospective treatment is a crucial yet challenging task. Unfortunately, patients' recall of medical information is generally poor and their information needs are not met. Effective information giving entails that oncologists help patients understand and recall the implications of their treatment, meanwhile fostering a trusting physician-patient relationship. Communication strategies that are often suggested to be effective are structuring and tailoring (cognition-oriented) but also are oncologists' expressions of caring or empathy (affect-oriented). Objective: The aim of this study is to provide evidence concerning the pathways linking physician communication to (improved) consultation outcomes for patients. More specifically, the aim is to determine the effects of information structuring and information tailoring, combined with physician caring, on information recall, satisfaction with information, and trust in the physician (primary objective) and on symptom distress (secondary objective). Methods: A randomized controlled trial, systematically testing the effects of information structuring and information tailoring, each combined with caring, in 2 video-vignette experiments (2×2 and 2×2×2 design). Using an online survey platform, participants will be randomly allocated (blinded) to 1 of 12 conditions in which they are asked to view a video vignette (intervention) in which an oncologist discusses a treatment plan for malignant lymphoma with a patient. The independent variables of interest are systematically varied across conditions. The outcome measures are assessed in a survey, using validated instruments. Study participants are (former) patients with cancer and their relatives recruited via online panels and patient organizations. This protocol discusses the trial design, including the video-vignette design, intervention pretesting, and a pilot study. Results: Data collection has now been completed, and preliminary analyses will be available in Spring 2019. A total of 470 participants completed the first part of the survey and were randomized to receive the intervention. Conclusions: The results of the proposed trial will provide evidence concerning the pathways linking physician information, giving skills to (improved) consultation outcomes for patients.