Background: Medical decision making profoundly influences the quality of life of advanced cancer patients and, hence, strongly depends on patients’ values and preferences. This observational study examines the type of values and preferences patients express in treatment decision consultations and how medical oncologists invite and react to such expressions. Methods: Advanced cancer patients for whom undergoing systemic treatment is medically not self-evident were identified. Patients (n = 43) were included when they met with a medical oncologist (n = 13) for the first time or to evaluate current treatment. Either one or two consultations were taped (total n = 64). Verbatim transcripts were analysed using MAXqda10 software. Independent coders identified and categorised patient expressions of values or preferences. Oncologists’ utterances preceding or following such expressions were coded. Results: Preliminary analysis (n = 20; 31%) shows that patient expressions of values and preferences were more frequent in first consultations (M =7) than in evaluation consultations (M = 2). Expressions often concerned (54%) either a general goal, a wish to receive treatment or an evaluation of a treatment option. One third of expressions (37%) were qualified as patient-initiated. Two thirds (63%) were qualified as oncologist-invited, triggered by e.g., a direct question, a referral to the importance of patients’ preferences or a treatment advice. Half of oncologists’ responses qualified as space reducing (51%), i.e., not responding or by providing information. Responses qualified as space providing (39%) were probe questioning, checking, reflecting or providing an alternative perspective. A minority of oncologist responses qualified as solving (10%), including offering advice or consideration time. Sequences (30%) instead of isolated patient expressions (70%) often occurred when oncologists gave space providing responses. Conclusions: Shared decision making in advanced cancer can be improved by teaching oncologists to invite and provide space to patient expressions of values and preferences. Particularly when evaluating current treatment, patients’ values and preferences should be put on the agenda.