Clinicopathologic characters and outcomes of pancreatic neuroendocrine tumors: comparison of functioning versus non-functioning tumors

Abstract

Purpose: Pancreatic neuroendocrine tumors (PNETs) are rare neoplasms with reported incidence of < 1 per 100,000 persons per year. PNETs are classified as functional or nonfunctional depending on their production of specific pancreatic endocrine hormones. This study presents the clinicopathologic characteristics and outcomes of PNETs experienced in a single institution. Methods: Between 1995 and 2011, clinicopathological data of 116 patients with PNETs proven by surgical pathology were reviewed retrospectively. Results: Of the 116 patients, mean age was 58.0-year-old. Median follow up was 60.1 months. Curative resection was achieved in 110 patients, and 24 patients (20.7%) had recurrence, which was most common in liver. The overall 5-year survival rate was 96.8%. Both the American Joint Committee on Cancer (AJCC) seventh staging (P=0.031) and World Health Organization (WHO) classification (2010) (P=0.011) correlated with prognosis. Functioning PNETs patients were younger than non-functioning PNETs patients at the time of diagnosis (P=0.008). Functioning PNETs had earlier T stage (P=0.001), AJCC seventh staging (P=0.001), and WHO classification (2010) (P=0.015) then non-functioning PNETs. By multivariate analysis, perineural invasion (odds ratio [OR], 10.151; 95% confidence interval [CI], 1.582— 65.147, P=0.015) and lymphovascular invasion (OR, 5.119; 95% CI, 1.642—15.956; P=0.005) were poor prognostic factors. Conclusion: Non-functioning PNETs have more advanced tumor than functioning PNETs at the time of diagnosis. AJCC seventh stage and WHO classification correlate with prognosis. Perineural invasion and lymphovascular invasion are poor prognostic factors.

Keywords

• neuroendocrine tumors
• pancreas
• prognosis
• survival rate