Descriptive epidemiology of gallbladder cancer (GBC): Real-world clinical characteristics and outcomes of patients in the US community oncology setting.

e16248 Background: GBC is a rare malignancy, marked by significant heterogeneity in presentation and outcomes between locally advanced (LA) and advanced (ADV) stages. This natural history study evaluated clinical characteristics and outcomes of patients with GBC treated in community oncology clinics to provide insights into this understudied disease. Findings aim to inform prognostication and treatment decisions while assessing how real-world outcomes align with published data. Methods: This retrospective cohort study included adults diagnosed with GBC in the U.S. Oncology Network from 2014 to 2022, with follow-up through 2023. Structured data from the iKnowMed electronic health record (EHR) system was used to assess patient characteristics, while chart abstraction was conducted on a random subset (n = 200) to evaluate treatment characteristics and outcomes, including overall survival (OS) and real-world progression-free survival (rwPFS). Multivariable Cox proportional hazard models evaluated factors associated with these outcomes. Results were stratified by stage (LA vs. ADV). Results: Among 2019 patients with GBC (mean age: 69.4 years, SD: 11.4), majority were female (67.6%) and White (59.7%) consistent with SEER data and known epidemiology of GBC. In the subset of 200 patients, 96.5% had disease stage assignment and of those, 56.0% (N = 108) had LA disease (Stage 0–III, IVA) and 44.0% (N = 85) had ADV disease (stage IVB). Median follow-up was 24.9 months (IQR: 15.1-45.7) for LA and 8.8 months (IQR: 5.6-13.2) for ADV. Comorbidities were more frequent in ADV patients (34.1% vs 29.6%), with diabetes being the most common (20.0% vs 18.6%). Chronic cholecystitis was more prevalent in LA patients (41.0%) compared to ADV (2.9%). Disease progression occurred in 33.3% of LA and 65.9% of ADV patients, with liver metastases being most common (21.3% for LA and 68.2% for ADV). Surgery was performed in 90.7% of LA patients, predominantly laparoscopic cholecystectomy. Among LA patients, 58.3% received adjuvant therapy, primarily capecitabine (33.3%), cisplatin+gemcitabine (25.4%), and gemcitabine monotherapy (17.5%), consistent with current literature. Among ADV patients, 89.4% initiated first-line therapy, most commonly cisplatin+gemcitabine (57.9%). Stage was significantly associated with outcomes. ADV patients had a greater risk of death (median OS 10.4 months, HR = 4.4, CI: 2.6–7.4) and progression (HR = 1.8, CI: 1.1–3.0) compared to LA patients (median OS 47.8 months, p < 0.0001). Conclusions: This analysis of real-world data from a large community cohort substantiates the unfavorable outcomes associated with GBC, despite the use of current standard of care regimens. These findings highlight the need for research focused on improving early detection and developing more effective treatment strategies for this challenging malignancy.