Abstract:Background：It is of great significance to understand the clinical distribution characteristics and direct causes of patients leaving the hospital without adviceof doctors，and propose corresponding measures to reduce the rate of against medical advice discharge. Methods：431 cancer patients who left without advice of doctors from January 1，2020 to September 30，2023 were retrospectively collected in acertain Tumor Hospital，and clinical information was collected for further analysis. Results：The against medical advice discharge rate is 0.2%. The average age of patients is 58.62，with males accounting for 59.9% slightly more than females（40.1%）. the mean length of stay in hospital was 8.01 days. 265 patients（61.5%）were admitted for the first time. There were 379 malignant tumor patients（87.9%），of which 187（49.3%）experienced metastasis. Against medical advice discharge are more common in oncology departments（242，56.1%）. The mainly malignant tumors are liver and gallbladder malignant tumors（38.8%），malignant neoplasm of bronchus and lung（14.8%），and pancreatic malignant tumors（7.9%）. The exacutive rates for surgery，anti-tumor drug therapy，and radiotherapy are 59.6%，76.4% and 84.6%，respectively. The top four direct reasons are：personal subjective reasons refusing the treatment（36.4%），critical illness，family members abandonment（12.5%），refusal of medicine treatment such as radiotherapy and chemotherapy（12.1%），and abandonment of surgery and invasive procedures due to risk（11.6%）. Conclusions：Against medical advice discharge is more common in the oncology department and first-hospitalized patients with a high mortality rate and poor prognosis cancer，and low adherence to treatment strategies，and it is the result of a combination of factors such as patients，diseases，and hospitals. This study provides a theoretical basis for the formulation of relevant intervention measures，which is of great significance for optimizing medical quality.