S3055 Trends in Endoscopic Therapy and Survival Outcomes in Patients With Early-stage Duodenal Neuroendocrine Tumors: A Surveillance Epidemiology and End Results (SEER) Analysis From 2004 to 2022

Introduction: Duodenal neuroendocrine tumors (D-NETs) are rare, yet are the most common type of small bowel neoplasms. Despite growth in endoscopic therapy (ET), current European guidelines recommend surgical resection (SR) over ET for high-risk D-NETs (i.e. tumor size >10 mm or invasion beyond the submucosa) due to risk of lymph node metastasis (LNM). We aim to investigate the trend and survival outcomes of patients with early-stage D-NETs treated with ET vs SR. Methods: The National Cancer Institute SEER program, the SEER17 registry, was used to extract data on adult patients (age ≥18 yr) with histologically confirmed D-NET with T1-2 staging, diagnosed in 2004-2022. We compared characteristics and trends in use of ET. Multivariate logistic regression was used to identify factors associated with ET. Cancer-specific survival (CSS) and overall survival (OS) were calculated using Kaplan-Meier’s (KM) estimate and the log-rank test. A Cox proportional hazards model was performed after controlling for other covariates. Results: 3,406 patients with T1-2 D-NET were identified (median age 65; 49.8% male; 53.1% White). Overall, 2,543 patients underwent tumor resection (1,761 ET vs 782 SR). Baseline characteristics were compared. There was an increase in ET over time (65.5% in 2012 to 82.0% in 2022). In multivariate logistic regression, ET was more likely in female patients (OR 1.22, 95% CI 1.00-1.49, P = 0.05), 2018-2022 (OR 2.88, 95% CI 1.39-5.98, P < 0.01), T1 stage (OR 2.38, 95% CI 1.57-3.60, P < 0.01), well-differentiated tumor (OR 1.38, 95% CI 1.00-1.89, P = 0.04), and no LNM (OR 21.8, 95% CI 12.80-36.96, P < 0.01). Median follow-up time was 43 months. The 5-year OS in ET was similar to SR (5-yr OS ET 82.0% vs 80.2%, P = 0.52). The 5-year CSS was significantly higher in ET group (5-yr CSS ET 98.1% vs 95.8%, P = 0.04). In subgroup analysis of tumor size 11–20 mm, 5-year CSS was similar in ET and SR (5-yr CSS ET 96.7% vs 95.5%, P = 0.57). In a Cox proportional hazards model, there was no significant difference in either overall mortality (hazard ratio (HR) 1.01, 95% CI 0.82-1.24, P = 0.90) or cancer-specific mortality (HR 0.69, 95% CI 0.38-1.25, P = 0.23) between ET and SR. Conclusion: We found a rising trend in the use of ET for D-NETs in the past decade. Five-year CSS was higher in the ET group, however, OS remained similar. In larger D-NETs (11-20 mm), patients who received ET and SR exhibited comparable long-term survival outcomes, indicating that ET is a viable treatment option.