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.