Background <p>Although most people in France wish to die at home, the majority of deaths still occur in hospitals. The choices of end-of-life care for patients with advanced cancer and how these preferences are shaped by interactions with relatives and healthcare professionals, remains poorly understood. This study aimed to explore how patients with advanced cancer develop and adjust these preferences, and to examine the roles of relatives, general practitioners, and oncologists in this process.</p> Methods <p>We conducted a single-centre longitudinal qualitative study at a French university hospital involving adults with advanced, incurable solid cancers. Participants were invited to take part in up to three semi-structured interviews conducted approximately one month apart. Interviews explored illness trajectory, preferences for place of end-of-life care and death, and discussions with relatives and healthcare professionals. Data were analyzed using thematic analysis.</p> Results <p>Eleven patients with metastatic solid tumours receiving care at a French university hospital completed at least two interviews between January and November 2023. Findings showed that although relatives were a key source of emotional support, patients deliberately limited their involvement in end-of-life discussions to protect them, resulting in relational distancing. A second layer of isolation concerned general practitioners, who were rarely consulted and not perceived as relevant interlocutors for end-of-life issues due to limited involvement in cancer care. In contrast, oncologists were identified as the main medical references, but primarily as technical experts focused on disease management rather than as professionals to address existential or end-of-life concerns. Consequently, patients often lacked a clearly identified professional with whom to discuss end-of-life preferences, reflecting communicative and decisional isolation. The longitudinal design further showed that these preferences were not fixed but evolved over time, often without a stable interlocutor to support reflection and discussion. When available, palliative care teams, or participation in the research interviews themselves, partially mitigated this gap by offering a space for reflection.</p> Conclusion <p>End-of-life preferences among patients with advanced cancer are strongly shaped by concerns for relatives, which may lead to limitations in discussions and contributes to a sense of isolation, with no clearly identified professional responsible for addressing these issues. Earlier, more proactive multidisciplinary involvement may help create spaces for reflection and support the expression of patients’ wishes.</p>