Clinical drivers and early outcomes of inpatient chemotherapy in gastrointestinal oncology: A retrospective cohort study.

Abstract

596 Background: Inpatient chemotherapy for gastrointestinal (GI) malignancies is used selectively for patients with urgent clinical needs or barriers to outpatient treatment, but indications, outcomes, and predictors of early mortality remain poorly defined. We characterized the clinical drivers and short-term outcomes of inpatient chemotherapy in GI oncology. Methods: We conducted a single-center retrospective cohort study of 84 adult patients with GI malignancies who received systemic chemotherapy during hospitalization at MD Anderson Cancer Center in Houston, Texas, between October 2024 and May 2026. Baseline demographics, clinical characteristics, and laboratory values at the time of chemotherapy initiation were collected. Categorical variables were summarized using frequencies and percentages and compared using Fisher’s exact test. Continuous variables were summarized descriptively and compared using the Wilcoxon rank sum-test. Primary outcomes were death within 14- and 30-day of inpatient chemotherapy. Results: The mean age was 54.96 ± 14.26 years. Most patients had metastatic disease (95.2%), treatment was given with palliative intent (96.4%), first line chemotherapy (76.2%) and cycle 1 administration (81%). Common clinical drivers for inpatient chemotherapy included high disease burden or rapid progression, hepatobiliary dysfunction, bowel or gastric outlet obstruction, and symptom control. Additional high-risk features included peritoneal involvement (53.5%), bowel obstruction (26.5%), and documented infection during admission (34.5%). Fourteen-day mortality was 5.9% and 30- day mortality was 12.2%. Patients who died within 14 days had higher white blood cell count (15.2 vs 8.4 K/ul, p=0.01) and more frequently had documented infection during admission (80.0% vs 31.7%, p=005). Patients who died within 30 days had significantly higher WBC count (14.75 vs 8.3 K/µL, p=0.001), absolute neutrophil count (12.89 vs 5.9 K/µL, p=0.01), and total bilirubin (2.5 vs 0.7 mg/dL, p=0.02) at the time of chemotherapy and more frequently had documented infection during admission (70% vs 30.6%, p=0.03) and more frequent required ICU transfer following chemotherapy (40% vs 5.6%, p=0.01). Conclusions: Inpatient chemotherapy in GI oncology was administered predominantly to patients with metastatic, palliative-intent disease, and substantial acute clinical burden. Early mortality was notable with leukocytosis, neutrophilia, hyperbilirubinemia, documented infection during admission and ICU escalation associated with death within 30 days. These findings may help refine patient selection and guide decision-making regarding inpatient chemotherapy use.