Objective To analyze the clinicopathological characteristics,diagnosis,treatment outcomes and prognosis of patients with pancreatic neuroendocrine tumors (PanNETs).Methods The clinicopathological characteristcs and prognostic factors of 88 patients who were diagnosed with pancreatic neuroendocrine tumors by postoperative pathology were analyzed retrospectively.The data included age,sex,symptoms,tumor size,pathological grades,TNM staging,treatment and follow up.Results There were 28 males and 60 females.The ratio of male to female was 1 ∶ 2.1,with a mean age of 42 (range 8～75) years.Of the 88 PanNETs,74(84.1％) were nonfunctional tumors.Using the WHO 2000 pathological classification system,there were 35 well differentiated endocrine tumors (WDET),29 well differentiated endocrine carcinomas (WDEC),and 24 poorly differentiated endocrine carcinomas (PDEC).Using the 7th AJCC TNM staging system,23(26.1％),46(52.3％),13(14.8％) and 6 patients (6.8％) were diagnosed to have stage Ⅰ,Ⅱ,Ⅲ and Ⅳ,respectively.The overall 5-year survival rate was 72.0 ％.Univariable analysis revealed tumor size,histopathological grades,TNM staging and radical surgery were associated with prognosis.Multivariate analysis showed histopathological grades,TNM staging and radical surgery were independent risk factors of survival.Conclusions PanNETs are rare pancreatic neoplasms with high heterogeneity and low malignant potential.PanNETs have various clinical manifestations and the preoperative misdiagnosis rate is high.A definitive diagnosis depends on pathological examination.The new TNM and pathological classification systems have good predictive abilities on survival.The majority of patients who received radical surgery or surgical comprehensive therapy have good prognosis.

Objective To analyze the prognostic importance of lymph node metastasis and the significance of regional lymphadenectomy in surgical treatment of nonfunctional pancreatic neuroendocrine tumors(NF-PanNET).Methods The clinical and pathological data of patients who underwent resection of NF-PanNET in Tianjin Medical University Cancer Institute and Hospital from January 2000 to December 2013 were retrospectively studied.The data included age,sex,tumor location,tumor size,lymph node metastasis,surgical resection margins,pathological grades and followed-up visits.Results Of 75 patients in this study,16 (21.3％) had lymph node metastases.Patients with larger tumors (＞3 cm) and higher tumor gradings (G3) had higher rates of lymph nodal metastasis.The overall 3-and 5-year disease-free survival (DFS) were 92.0％ and 89.2％ respectively.The 5-year DFS for patients with and without nodal metastasis were 75.0％ and 93.0％ (P＜0.05) respectively.Significantly lower 5-year DFS rates were found in patients with lymph nodal metastases,large tumor sizes (＞3 cm),high pathological gradings (G3) and positive surgical resection margins (all P＜0.05).Multivariable analysis showed that lymph nodal metastasis and surgical resection margin were independent factors associated with DFS (all P＜0.05).Conclusions Patients with NF-PanNET with lymph node metastasis had significantly higher risks of recurrence and metastasis.Patients with large tumor sizes (＞3 cm) had a higher rate of lymph node metastasis,and radical surgery with lymph node dissection is recommended for these patients.