Terminally ill cancer patients do not engage in end-of-life (EOL) care discussions or do so only when death is imminent, despite guidelines for EOL care discussions early in their disease trajectory. Most studies on patient-reported EOL care discussions are cross sectional without exploring the evolution of EOL care discussions as death approaches. Cross-sectional studies cannot determine the direction of association between EOL care discussions and patients' prognostic awareness, psychological well-being, and quality of life (QOL). We examined the evolution and associations of accurate prognostic awareness, functional dependence, physical and psychological symptom distress, and QOL with patient-physician EOL care discussions among 256 terminally ill cancer patients in their last six months by hierarchical generalized linear modeling with logistic regression and by arranging time-varying modifiable variables and EOL care discussions in a distinct time sequence. The prevalence of physician-patient EOL care discussions increased as death approached (9.2%, 11.8%, and 18.3% for 91–180, 31–90, and 1–30 days before death, respectively) but only reached significance in the last month. Accurate prognostic awareness facilitated subsequent physician-patient EOL care discussions, whereas better patient-reported QOL and more anxiety symptoms hindered such discussions. The likelihood of EOL care discussions was not associated with levels of physical symptom distress, functional dependence, or depressive symptoms. Physician-patient EOL care discussions for terminally ill Taiwanese cancer patients remain uncommon even when death approaches. Physicians should facilitate EOL care discussions by cultivating patients' accurate prognostic awareness early in their cancer trajectory when they are physically and psychologically competent, with better QOL, thus promoting informed and value-based EOL care decision making.