Significance of lymph node metastasis in pancreatic neuroendocrine tumors.

Abstract

210 Background: Pancreatic neuroendocrine tumor (PNET) is uncommon, and its prognosis is generally better than that of pancreatic cancer. Although some PNET patients have lymph node metastasis, its effect on their prognosis is unclear, lymph node dissection for PNET is controversial. Our study aimed to clarify the significance of lymph node metastasis in PNET. Methods: We retrospectively examined 83 PNET patients who underwent pancreatic resections at Kumamoto University Hospital, Saiseikai Kumamoto Hospital and Kumamoto Regional Medical Center from April 2001 to December 2014. We excluded NET G3 from them. Their clinicopathological parameters were analyzed by the absence or presence of lymph node metastasis, and with regard to disease-free survival (DFS) and overall survival (OS). Results: Although 5-year DFS was lymph node metastasis group: 73.3%, and no lymph node metastasis group: 85.0% (P = 0.474); and 5-year OS was lymph node metastasis: 91.7% and no lymph node metastasis: 96.2% (P = 0.055), lymph node metastasis was not an independent risk factor for DFS or OS in multivariate analysis. However, tumors larger than 1.8 cm were found to be an independent prognostic factor. Conclusions: Although lymph node metastasis was not an independent prognostic factor, tumors larger than 1.8 cm were an independent prognostic factor, and warrant lymph node dissection for PNET patients with tumors of this size.