Objective Advances in oncology increasingly result in protracted disease trajectories for patients with incurable cancer. In this disease phase, patients are aware of the incurable nature of cancer although they are not yet approaching the last phase of life. We explored the challenges for patients confronted with protracted incurable cancer. Design Ethnographic study (2015–2017) based on conversations with patients, observations at a day-care unit and a selection of information from the medical records of patients who died during the study period. Setting The day-care unit of a comprehensive cancer centre in the Netherlands. Participants Nineteen patients with stage IV breast cancer (in remission, >1 year after diagnosis) and 11 patients with stage IV lung-cancer (in remission, >6 months after diagnosis). Results In patients who had died during the study period, the treatment response often fluctuated between stable, remission and progression throughout the course of the disease. Patients reported that this fluctuation could be overwhelming. However, as patients grew accustomed to having protracted incurable cancer, the distress associated with fluctuations (perceived in scan results) slowly faded. Patients reported that cancer became part of who they were. At the day-care unit, most patients talked about their disease in an optimistic or neutral way and expressed delight in life. They often expressed gratefulness for the possible prolongation of life, expressed hope and tried to stay optimistic. This was frequently reinforced by optimistic doctors and nurses. Relatives, however, could downplay such optimism. Moreover, some patients acknowledged that hope was qualified by their personal challenges regarding their disease. Conclusions In situations where tumours remained in remission or were stable for extended periods, patients grew accustomed to having cancer. At the day-care unit, medical professionals typically encouraged an attitude of being hopeful and optimistic, which could be downplayed by ...