Real-world outcomes of FOLFOX with or without bevacizumab in small bowel and ampullary adenocarcinoma: A propensity-matched analysis.

e16488 Background: Small bowel adenocarcinoma (SBA) and ampullary adenocarcinoma (ampullary AC) are rare gastrointestinal (GI) malignancies. Treatment strategies are largely extrapolated from colorectal cancer, where oxaliplatin-based regimens are the most common first-line therapy in advanced disease. Although bevacizumab is considered safe in metastatic SBA, its efficacy remains unproven, and evidence is limited to small retrospective studies. We assessed the association of adding bevacizumab to FOLFOX with survival and toxicity in a large real-world cohort. Methods: We conducted a retrospective cohort study using the TriNetX Global Collaborative Network (January 2000-December 2025), including data from 105 healthcare organizations. Adults (≥18 years) with SBA or ampullary AC treated with FOLFOX with or without bevacizumab were identified. Cohorts were propensity score-matched on age, sex, race, comorbidities, and metastatic sites. Outcomes included overall mortality, GI perforation, bleeding, venous thromboembolism (VTE), hospital admission, and emergency department (ED) visits. Kaplan-Meier and Cox proportional hazards models were used for time-to-event analyses. Results: After matching, 818 patients were included in each cohort. In the FOLFOX + bevacizumab cohort, mean age was 66.1 ± 12.0 years and 53.8% were male; 63.7% were White, 13.8% Black, 5.6% Asian, 12.0% Unknown/Other, and 4.4% Hispanic/Latino. Over a median follow-up of 13 months, FOLFOX + bevacizumab was associated with higher overall mortality compared with FOLFOX alone (55.3% vs 45.2%; HR 1.24 [95% CI 1.1-1.4]; p = 0.002) and shorter median OS (15.1 vs 19.5 months). Rates of GI perforation (15.5% vs 16.7%; HR 0.90 [95% CI 0.71-1.15]; p = 0.39), GI bleeding (13.1% vs 13.6%; HR 0.96 [95% CI 0.73-1.25]; p = 0.74), and VTE (19.1% vs 21.4%; HR 0.88 [95% CI 0.71-1.09]; p = 0.23) were similar between groups. Hospital admissions were higher in the FOLFOX + bevacizumab cohort (2.8% vs 1.3%; HR 2.1 [95% CI 1.0-4.3]; p = 0.04). Findings were consistent at 5-year follow-up. Conclusions: In this real-world cohort, the addition of bevacizumab to FOLFOX was not associated with improved survival and was associated with higher healthcare utilization. Prospective, disease-specific studies are needed to define its role in this population. Outcomes at median 13-month follow-up after propensity matching (FOLFOX + bevacizumab vs FOLFOX). Outcome % vs % HR p Overall mortality 55.3 vs 45.2 1.24 0.002 Hospital admission 2.8 vs 1.3 2.1 0.04 ED visit 45.2 vs 42.4 1.02 0.75 GI perforation 15.5 vs 16.7 0.90 0.39 GI bleeding 13.1 vs 13.6 0.96 0.74 VTE 19.1 vs 21.4 0.88 0.23