P-0172 - Surgical Treatment of Malignant Nonfunctioning Neuroendocrine Tumors of the Pancreas

Abstract

Background: Surgical technique of treatment of these tumors may be similar to the treatment of adenocarcinoma or organ preserving technique is preferable in case when diagnosis of neuroendocrine tumors was confirmed in preoperative period. Neuroendocrine tumors of the pancreas have a more favorable course and prognosis comparing to pancreatic adenocarcinoma and occupy approximately 1-2% of all oncologic pathology of the pancreas. Aims: Assessment of the efficacy, safety and long-term outcome of treatment of patients with non-functioning malignant neuroendocrine tumors (MNET) of pancreas. Methods: From 2004 to 2012 we had treated 87 patients with nonfunctioning neuroendocrine tumors of the pancreas, in 65 (74.7%) patients had malignant tumors, neuroendocrine tumor G2 - 43 (66.2%) patients and neuroendocrine carcinoma G3 - 22 (33.8%) (WHO classification, 2010). Localization of MNET were head of the pancreas in 27 (41.5%) patients, in the body - 15 (23.1%), in the tail - 19 (29.2%), in the uncinate pancreas - 4 (6.2%). Before to surgery, the diagnosis of neuroendocrine tumor of the pancreas was verified in 12 (18.4%) patients, intraoperatively in 8 (12.3%) patients. In all cases, the diagnosis was confirmed by histological and imunohistochemical researches. It should also be noted that, in further study on neuroendocrine tumors were re-analyzed by histological specimens of patients with 3-year disease-free survival in patients with intraductal adenocarcinoma, for 4 patients a diagnosis was changed retrospectively on malignant neuroendocrine tumor of the pancreas (3 patients - G2 and 1 patient - G3 MNET). Results: Pancreaticoduodenectomy (PDE) (Whiple procedure) had performed for 19 (29.2%) patients, 6 (9.2%) patients pylorus preserving PDE, in 2 (3.1%) cases - PDE and liver resection, total pancreatectomy in 1 (1.5%) cases, left side pancreatectomy with splenectomy - 16 (24.6%), spleen-preserving left side pancreatectomy - 7 (10.8%), laparoscopic left side pancreatectomy with splenectomy - 4 (6.2%), central pancreatectomy - 3 (4,6%), palliative operation - 3 (4,6%), explorative laparotomy 1 (1.5%). Postoperative complications were happened with 24.6% of patients, 3 patients (4.6%) had postoperative acute pancreatitis, 12 patients (18.5%) had pancreatic fistula (grade A - 8 patients, Grade B - 3 patients, Grade C - 1 patient), and 1 (1.5%) patient had intra-abdominal bleeding. The overall 5-years survival without metastasis was 67.4%, in case of the metastasis presence only into the regional lymph nodes - 52.7%, when metastases were detected in the liver 5-years survival was 14.2%. The disease-free survival in patients with the absence of distant metastases was 42.6 months and 11.2 with distant metastases. Conclusion: Laparoscopic surgery and organ-preserving surgery are safe and effective operations for local malignant nonfuctioning neuroendocrine tumors. The presence of distant metastases of malignant neuroendocrine tumors of the pancreas decrease the long-term outcome. But are not contraindications for multivisceral resection surgery and give a better long-term outcome compared to palliative surgery. The presence of metastases in regional lymph nodes were not significantly impair long-term outcome.