ObjectiveAlong with aging, the elderly population with cancers is increasing. The costs of end-of-life (EOL) care are particularly high among cancer patients. The purpose of this study was to investigate the trends in medical costs in the last year of life among older adults with cancer.Design, setting, and participantsUsing the Health Insurance Review and Assessment Services (HIRA) database for the period 2016–2019, we identified older adults aged ≥ 65 years who had a primary diagnosis of cancers and high-intensity treatment at least once in the intensive care unit (ICU) of tertiary hospitals.Main outcomes and measuresHigh-intensity treatment was defined as receiving at least one of the following treatments: cardiopulmonary resuscitation, mechanical ventilation, extracorporeal membrane oxygenation, hemodialysis, and transfusion. The EOL medical treatment costs were calculated by dividing periods 1, 2, 3, 6, and 12 months from the time of death, respectively.ResultsThe mean total EOL medical expense per older adult during the year before death was $33,712. The cost of EOL medical expenses for three months and one month before subjects’ death accounted for 62.6% ($21,117) and 33.8% ($11,389) of total EOL costs, respectively. Among subjects who died while receiving high-intensity treatment in the ICU, the costs associated with medical treatments that occurred during the last month before death were 42.4% ($13,841) of the total EOL expenses during the year.ConclusionThe findings indicate that EOL care expenditures for the older population with cancer are highly concentrated until the last month. The intensity of medical care is an important and challenging issue in terms of care quality and cost suitability. Efforts are needed to properly use medical resources and provide optimal EOL care for older adults with cancer.