BackgroundPeople who die from cancer (cancer decedents) may experience unpleasant and distressing symptoms which cause them to present to unscheduled care. Unscheduled care is unplanned care delivered by general practitioner out-of-hours and emergency departments. Use of unscheduled care can disrupt treatment plans, leading to a disjointed patient care and suboptimal outcomes.ObjectivesThis systematic review aimed to identify factors associated with unscheduled care use by cancer decedents.MethodSystematic review with narrative synthesis of seven electronic databases (PubMed; Medline; Embase; Cochrane Database of Systematic Reviews; Cochrane Central Register of Controlled Trials; Web of Science; Cumulative Index to Nursing and Allied Health Literature) from inception until 01 January 2020. All observational and experimental studies were included, irrespective of their research design.ResultsThe search yielded 238 publications included at full-text, of which 47 were included in the final review and synthesis. Unscheduled care use by cancer decedents was influenced by multiple factors, synthesised into themes: demography, clinical and patient, temporal, prescribing and systems. Cancer decedents who were older, men, had comorbidities, or lung cancer, were most likely to use unscheduled care. Unscheduled care presentations were commonly due to pain, breathlessness and gastrointestinal symptoms. Low continuity of care, and oncology-led care were associated with greater unscheduled care use. Access to palliative care, having an up-to-date palliative care plan, and carer education were associated with less unscheduled care use.ConclusionThe review identifies multiple factors associated with unscheduled care use by cancer decedents. Understanding these factors can inform future practice and policy developments, in order to appropriately target future interventions, optimise service delivery and improve the patient journey.PROSPERO registration numberCRD42016047231.