Background: Potentially avoidable emergency department (ED) visits are considered an indicator of the quality of cancer care.

Objective: To investigate the causes of ED visits of patients with advanced cancer.

Methods: We included in this analysis the visits to the ED of patients with advanced cancer in a tertiary cancer center in Mexico City, registered the reasons for their visit, and classified them as potentially avoidable or not by three independent observers.

Results: Seventy-seven patients were included, and 69% had at least one visit to the ED. Fifty-seven percent of visits were classified as potentially avoidable. The most common causes of visiting the ED were: pain, gastrointestinal disorders and ascites. Patients with gastrointestinal and genitourinary tumours had a higher frequency of unavoidable ED visits compared to patients with other tumours (43.3% versus 20.7%, p 0.03).

Conclusion: A significant proportion of patients with advanced cancer visit the ED and many of these visits were classified as potentially avoidable based on expert judgment and adapted criteria. These findings highlight the need for further research and context-specific strategies, such as care and early palliative integration, to safely reduce unnecessary ED use and enhance quality of life in low- and middle-income settings.