BackgroundShared decision-making (SDM), which increases the patient’s well-being, adherence, and success of treatment, is becoming increasingly important in medicine and especially in oncology. To empower patients to participate more actively in consultations with their physicians decision aids have been developed. In non-curative settings, such as the treatment of advanced lung cancer, decisions differ substantially from the curative setting, as uncertain gains in terms of survival outcomes and quality of life have to be weighed against the severe side effects of treatment regimens. There is still a lack of tools developed and implemented for such specific settings in cancer therapy that support shared decision-making. The aim of our study is to evaluate the effectiveness of the HELP decision aid.MethodsThe HELP-study is designed as a randomized, controlled, open monocenter trial with two parallel groups. The intervention consists of the use of the HELP decision aid brochure, accompanied by a decision coaching session. The primary endpoint is clarity of personal attitude as operationalized by the Decisional Conflict Scale (DCS) after the decision coaching. Randomization will be performed as stratified block randomization according to the characteristic of preferred decision-making at baseline with a 1:1 allocation.The participants in the control group get usual care, i.e., the doctor-patient conversation takes place without preliminary coaching and deliberation about their preferences and goals.DiscussionDeveloping decision aids (DA) for (lung) cancer patients with limited prognosis should empower patients to address these aspects and include information about “Best Supportive Care” as a treatment option. Using and implementing the decision aid HELP can not only give patients the possibility to include their personal wishes and values in the decision-making process, but also raise the awareness of shared decision-making itself among these patients and their physicians.Trial registrationGerman Clinical Trial Register DRKS00028023. Registered on 8 February 2022.