High mortality following unplanned breast cancer hospitalizations.

e23408 Background: The majority of breast cancer care occurs in outpatient settings, and data derived from hospital admissions remain scarce. Methods: A retrospective analysis was perfomed of unplanned admissions to a dedicated breast cancer unit at the National Cancer Institute, Brazil, over 18 months period. Demographic, clinical, and hospitalization characteristics were examined. Causes of admission were classified as disease progression, treatment-related toxicity, or non-oncologic complications. The primary outcome was in-hospital mortality, evaluated using multivariable logistic regression. Results: A total of 731 patients were included, accounting for 1053 unplanned admissions. Self-reported race was Black, White, and Asian in 62.1%, 37.5%, and 0.4% of patients, respectively. Median age at diagnosis was 54 years (IQR, 45.0–63.5). Most patients had advanced disease (stage III: 44.7%; stage IV: 27.3%). Tumor subtypes were hormone receptor–positive/HER2-negative in 59.4%, HER2-positive in 21.6%, and triple-negative in 14.8%. Most patients experienced one unplanned hospitalization (71.7%); 19.7% had two, and 8.6% had three or more. The median length of stay was 8 days (IQR, 5–13.0), and the median time to death was 8 days (IQR, 4–17). Readmissions occurred in 28.3% of patients, including 14.1% within 30 days. Admissions were mainly due to disease progression (63.0%); followed by non-oncologic complications (22.7%), and treatment-related toxicity (14.2%). In-hospital mortality was 39.1% and independent predictors of death were age (OR 1.02, 95% CI 1.00–1.03; p = 0.019), number of hospitalizations (OR 1.51, 95% CI 1.21–1.92; p = 0.001), poor performance status at the last admission (ECOG ≥2; OR 4.92, 95% CI 2.64–9.89; p < 0.001), last admission due to disease progression (OR 2.90, 95% CI 1.88–4.53; p < 0.001). These variables were adjusted by tumor subtype, and ongoing treatment during the last hospitalization. Conclusions: Unplanned admissions to a dedicated breast cancer unit were associated with high in-hospital mortality, particularly among patients with advanced disease, poor performance status, and repeated admissions. Early identification of high-risk patients may facilitate timely integration of palliative care strategies.