BACKGROUND: Neuroendocrine neoplasms (NENs) are relatively rare, accounting for 1-2% of all gastrointestinal (GI) tumors. The liver is the most common site of secondary NEN metastases; however, hepatic neuroendocrine neoplasm (PHNEN) arising as a primary tumor is very rare. In the literature, fewer than 150 cases have been reported. We sought a populationbased registry to identify and describe the incidence, management, and survival of PHNEN.
METHODS: Patients were identified from the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2017 using SEER*Stat software. A chi-squared test was used to compare the clinicopathological characteristics. Kaplan–Meier analysis and log-rank tests were used for survival comparisons. A Cox proportional model was implemented for multivariate analyses of the patient population and hazard ratios (HR) and corresponding confidence intervals (CI) were generated.
RESULTS: Among 71,893 GI NEN patients identified, 416 patients (0.6%) were diagnosed with PHNEN. Most of them were older than 60 years of age (63%), female (52.3%), and non-Hispanic whites (65.4%). About one-third of patients had localized disease at presentation and 56.4% had histology consistent with neuroendocrine carcinoma (NEC). In a multivariate analysis, patients with grade III (poorly differentiated) or IV (undifferentiated/anaplastic) disease, vs. grade I (well differentiated), were associated with decreased cause specific survival (CSS) and overall survival (OS). Patients with neuroendocrine tumor histology were associated with a better CSS (HR 0.36, CI 0.21-0.65) and OS (HR 0.46, CI 0.28-0.75) than NEC histology. Patients who underwent surgical resection were also associated with better CSS (HR 0.19, CI 0.11-0.36) and OS (HR 0.19, CI 0.11-0.33) when compared to those that did not undergo surgery.
CONCLUSIONS: We describe a large series of cases with PHNEN, identified from the US population-based registry, that helps better characterize this uncommon disease. We found tumor grade, not SEER historical stage (local, regional, or distant), is an independent prognostic factor. Despite its rarity, PHNENs that are well-differentiated NETs can still have improved survival when surgical resection is considered.