Comparison of tumor characteristics and survival between esophageal and other gastroenteropancreatic neuroendocrine neoplasms.

Abstract

e15556 Background: Neuroendocrine neoplasms (NEN) of esophagus are extremely rare. Limited information is available on survival of these tumors. The objective of this study was to define the clinicopathologic predictors of overall survival (OS) in esophageal NEN, and to compare them with the other gastroenteropancreatic NEN (GEP-NEN). Methods: Esophageal NEN were selected from the National Cancer Database (2004–2013). Multivariable analysis and Kaplan–Meier method were performed. The prognostic factors for GEP-NEN were derived from literature including WHO classification and AJCC TNM classification. Results: Of 802 selected patients with esophageal NEN, 97.5% were NEC and only 2.5% typical NET. The median age for NET was 58 vs. 66 for NEC (p = 0.007). NET more commonly presented in females (60%) compared to NEC wherein 68% patients were male. Most of the NEC were grade III/IV and > 4 cm, while most NET were grade I/II and < 4 cm. They most frequently metastasized to the liver. 10.7% of patients with esophageal NEN underwent esophagectomy while 86.5% had no surgery; 68.5% had adjuvant and 6.6% neoadjuvant therapy. Multivariable analysis showed that tumor > 4 cm (hazard ratio (HR) 1.45; P = 0.013), stage III and IV (HR 2.27; p = 0.030, and HR 4.02; P < 0.001, respectively) were associated with significantly worse OS, while esophagectomy (HR 0.30; P = 0.019) and neoadjuvant therapy (HR 0.35; p = 0.006) were predictors of better OS. The 5-year OS rate was 12% for all esophageal NEN (95% CI, 10-15): 89% for NET and 9% for NEC. Pancreatic NET are generally > 2 cm and NEC have an average size of 4 cm. The factors associated with worse prognosis in pancreatic NEN include positive surgical resection margins, lymph node metastases, advanced TNM stage, vascular invasion and distant metastasis. The 5-year OS for patients with pancreatic NET and NEC is 65% and 16%, respectively. NET of ileum are < 2 cm in 47% of cases, and the 5-year OS is about 60%. Tumor stage is the most important predictor of survival. The malignant potential is retained for ileal NET > 1 cm. Only Stage III vs. Stage IV has a better OS. The G3 NEC and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN) have poor OS and variable median survival time reported up to 40 months. Conclusions: Using the largest dataset of esophageal NEN to date, the major independent predictors of OS include tumor size, stage, esophagectomy, and chemotherapy. The majority of esophageal NEN are NEC. Their OS is similar or slightly higher in comparison to ileal NEC but poor in comparison to similar tumors presenting in the pancreas.