Patients’ awareness of their prognosis is generally assumed to be essential for informed decision making and advance care planning. Indeed, prognostic awareness is related to a preference for comfort care, documenting preferences in a will and do-not-resuscitate orders. Nevertheless, worldwide, an estimated half of the patients with advanced cancer misunderstand their prognosis. Some patients do not want to know. In contrast, others may have an incorrect understanding despite a wish to know their prognosis. This may affect patients' decisions, which may be at odds with their preference. 

We need more insight into the extent to which prognostic unawareness is in line with patients’ preference. Also, we need to know the characteristics of patients who prefer not to know as well as the characteristics of the patient and context that lead to unawareness despite a wish to know. Furthermore, we need more evidence on the effect of physicians’ prognostic disclosure, and of different methods to do so, on patients’ prognostic understanding, treatment preferences, emotional response and satisfaction.