Unplanned Readmission among Patients with Advanced Cancer on Active Treatment: Multi-Center, Retrospective Study

Purpose: Unplanned readmissions of patients with cancer increase healthcare costs and disrupt care. Although well-studied in surgical oncology, data on patients receiving active treatment for advanced cancer remain limited. This study examined the causes, clinical characteristics, and outcomes of unplanned readmissions. Materials and Methods: This retrospective, multicenter study included patients with advanced solid tumors from six South Korean university hospitals who had unplanned readmissions within 1 month of prior hospitalization in 2019. Patients with terminal cancer who did not receive active treatment were excluded. Readmissions were categorized as Cancer Progression (e.g., worsening symptoms), treatment-related (e.g., therapy complications), or other (e.g., non-cancer conditions). Additional unplanned hospital use within 1 month post-discharge was analyzed in survivors with 6-month follow-up data. Results: Among the 542 patients, readmissions were classified as cancer progression (42.6%), treatment-related (37.3%), or other (20.1%). The cancer progression group had the longest hospital stay (median, 12 days) and the highest mortality (23.4%). The Treatment-Related group had shorter stays (8 days) and lower mortality (8.4%). Among the 445 survivors, 24.9% had unplanned hospital visits within 1 month post-discharge. Home discharge increased the likelihood of these events (adjusted odds ratio: 4.82 for readmissions, 2.65 for emergency department visits). Conclusion: Cancer progression was the leading cause of readmission and was associated with prolonged hospital stays and high mortality rates. Home discharge is a key predictor of early additional unplanned hospital visits, indicating the need for careful post-discharge monitoring in this population.