Overestimated Oncologic Significance of Lymph Node Metastasis in G1 Nonfunctioning Neuroendocrine Tumor in the Left Side of the Pancreas.

Abstract

Recent studies have expounded on the oncologic significance of lymph node metastasis in nonfunctioning (NF) neuroendocrine tumors (NETs) of the pancreas and suggest regional lymph node dissection for treating pancreatic NET. We tested this recommendation in NF pancreatic NET-G1, as these tumors are generally small and suitable for function-preserving minimally invasive pancreatectomy.From January 2005 to December 2014, medical records of patients who underwent pancreatectomy for pathologically confirmed NF NET-G1 of the left side of the pancreas were retrospectively reviewed. Oncologic outcomes were compared between limited pancreatectomy and distal pancreatosplenectomy.Thirty-five patients (14 males and 21 females) with a mean age of 55.9 ± 11.4 years were enrolled in this study. Six patients (17.1%) underwent distal pancreatosplenectomy. Limited pancreatectomies comprised 15 spleen-preserving distal pancreatectomies (42.8%), 10 enucleations (28.6%), and 4 central pancreatectomies (11.4%). Lymph node metastasis was not found in 6 patients who underwent distal pancreatectomy with a splenectomy; meanwhile, the others were regarded as pNx since no lymph node retrieval was attempted during the limited pancreatectomy. Overall disease-free survival was 36.5 months (95% confidence interval [CI]: 25.9–47.1) and no tumor-related mortality was noted. Minimally invasive pancreatectomy (P = 0.557) and limited pancreatectomy (P = 0.758) showed no adverse impact in treating NF NET-G1 of the left side of the pancreas.The oncologic significance of lymph node metastasis is overestimated in NF NET-G1 of the left side of the pancreas. Routine conventional distal pancreatosplenectomy to retrieve regional lymph nodes may be too excessive in treating NF NET-G1 of the distal pancreas.