Ampullary Neuroendocrine Tumors: Insight into a Rare Histology

Background: Ampullary neuroendocrine tumors (NETs) make up < 1% of all gastroenteropancreatic NETs, and information is limited to case series. This study compares patients with ampullary, duodenal, and pancreatic head NETs.

Methods: The National Cancer Database (2004-2016) was queried for patients with ampullary, duodenal, and pancreatic head NETs. Survival was evaluated using Kaplan-Meier analysis and Cox regression.

Results: Overall, 872, 9692, and 6561 patients were identified with ampullary, duodenal, and pancreatic head NETs, respectively. Patients with ampullary NETs had more grade 3 tumors (n = 149, 17%) than patients with duodenal (n = 197, 2%) or pancreatic head (n = 740, 11%) NETs. Patients with ampullary NETs had more positive lymph nodes (n = 297, 34%) than patients with duodenal (n = 950, 10%) or pancreatic head (n = 1513, 23%) NETs. On multivariable analysis for patients with ampullary NETs, age (hazard ratio [HR] 1.03, p < 0.0001), Charlson-Deyo score of 2 (HR 2.3, p = 0.001) or ≥3 (HR 2.9, p = 0.013), grade 2 (HR 1.9, p = 0.007) or grade 3 tumors (HR 4.0, p < 0.0001), and metastatic disease (HR 2.0, p = 0.001) were associated with decreased survival. At 5 years, the overall survival (OS) for patients with ampullary, duodenal, and pancreatic head NETs was 59%, 71%, and 50%, respectively (p < 0.0001), whereas the 5-year OS for patients with ampullary, duodenal, and pancreatic head NETs who underwent surgery was 62%, 78%, and 76%, respectively (p < 0.0001).

Conclusions: Ampullary NETs were more likely to present with high-grade tumors and lymph node metastases. Based on the clinicopathologic and survival data, ampullary NETs have a unique underlying biology compared with duodenal and pancreatic head NETs.