家庭成员可以支持提前护理规划的对话。然而，家庭参与提前护理规划如何实现目标一致的护理仍不清楚。为了探讨家庭参与如何影响晚期癌症患者和其家属实现目标一致护理的提前护理规划过程在日本的情况，本研究采用半结构化深度访谈与家庭系统理论指导下的主题分析进行定性研究。日本两家三级医院的医学肿瘤科部门。研究样本由13名晚期癌症患者、10名家属和9名他们照顾的医疗专业人员组成。共进行了25次访谈，其中包括7个患者和家属的二人访谈和18个个人访谈。研究确定了四个主题：患者和家属的特点及其对疾病和提前护理规划的看法；家庭背景和沟通；与医疗专业人员的互动以及社会和文化影响；以及家庭成员的接受、准备和信心。观察到家庭参与在个体层面和跨代之间是多变的。家庭成员为患者提供了工具性和情感性支持，促进了提前护理规划过程。家庭参与使家庭成员更好地准备实现患者的愿望。它增加了家庭成员在代理决策中的信心。确定了家庭参与可能实现目标一致护理的两种机制：家庭成员的支持提供和准备实现患者愿望。医疗专业人员应评估家庭参与提前护理规划的准备程度，并为其进行准备的时间。

Family members can support advance care planning conversations. However, how family involvement in advance care planning operates to achieve goal-concordant care remains unclear.To explore how family involvement impacts the process of advance care planning for advanced cancer patients and their family members to achieve goal-concordant care in Japan.Qualitative study incorporating semi-structured in-depth interviews with thematic analysis informed by Family Systems Theory.Medical oncology departments at two tertiary hospitals in Japan. A purposive sample of 13 advanced cancer patients, 10 family members and 9 healthcare professionals who cared for them.Twenty-five interviews were conducted, comprising 7 dyads of patients and their family members and 18 individual interviews. Four themes were identified: characteristics of patients and family members and their views on illness and advance care planning; family context and communication; interactions with healthcare professionals and societal and cultural influences; and family members' acceptance, preparation and confidence. Family involvement was observed as being variable at an individual level and also across generations. Family members provided patients with the instrumental and emotional support that facilitated the advance care planning process. Family involvement enabled family members to better prepare for realising patients' wishes. It increased family members' confidence in surrogate decision-making.Two mechanisms of how family involvement may enable goal-concordant care were identified: family members' support provision and their preparation for realising patients' wishes. Healthcare professionals should assess family's readiness to engage in advance care planning, and the time required to prepare them for the process.