Risk of metastasis and survival in patients with T1-2 non-ampullary duodenal neuroendocrine tumors undergoing different treatment strategies

BACKGROUND: Optimal management of T1-2 non-ampullary duodenal neuroendocrine tumors (NAD-NETs) remains controversial, particularly for intermediate-sized tumors (11-20 mm), due to limited evidence. This study aimed to quantify real-world metastasis risk and compare long-term survival after endoscopic therapy (ET) or surgical therapy (ST) for T1-2N0M0 NAD-NETs. METHODS: Patients were identified from the Surveillance, Epidemiology, and End Results (SEER) database and divided into two cohorts: Cohort A (n = 2101), including T1-2 NAD-NETs for metastasis risk-factor analysis; and Cohort B (n = 1496), including T1-2N0M0 NAD-NETs treated with ET or ST for survival comparison. Multivariable logistic regression was performed to assess factors associated with metastasis risk in Cohort (A) Propensity score matching was performed to balance covariates in Cohort (B) Cancer-specific survival (CSS) and overall survival (OS) were calculated and compared between the ET and ST groups. RESULTS: Overall metastasis incidence at diagnosis was 9.42% (198/2101). Independent metastasis predictors included tumor size 11-20 mm (OR = 4.30, 95% CI:3.00-6.16) and > 20 mm (OR = 14.65, 95% CI:9.38-22.94), and muscularis propria (MP) invasion (OR = 4.94, 95% CI:2.41-10.74). Of the 1496 patients with T1-2N0M0 NAD-NETs, the long-term prognosis was comparable between ET and ST (after matching, 5-year CSS: 99.0% vs. 97.1%, P = 0.031; 5-year OS: 84.6% vs. 87.4%, P = 0.37). Subgroup analyses confirmed equivalent survival for ET versus ST across those measuring 11-20 mm (CSS 97.4% vs. 98.1%, P = 0.694) and those measuring > 20 mm (CSS 100% both). CONCLUSION: ET provides comparable long-term survival versus surgery for T1-2N0M0 NAD-NETs and ET could be a viable strategy for well- to moderately differentiated NAD-NETs of 11-20 mm without MP invasion.