Abstract:

Objective To investigate the clinical features, pathological characteristics, surgical strategies, and prognostic factors of malignant non-functioning pancreatic neuroendocrine tumors (PNETs). Methods The clinical records of 37 patients with malignant non-functioning PNETs who underwent curative surgery were retrospectively analyzed. The data included sex, age, symptoms, pathological characteristics, surgical strategies, and prognosis. Based on the extent of resection, patients were divided into two groups, i.e. the non-extended resection group (n=25) and extended resection group (n=12). T test was adopted to compare continuous variables. Fisher's exact test was used to compare categorical variables. Kaplan-Meier method was used for survival analysis and univariate analysis. Log-rank test was adopted to evaluate the differences of survival rates of two groups. Multivariate analysis was performed by the Cox regression model. Results Among 37 patients, 20 of them were males (54%) and 17 of them were females (46%). Their age ranged from 28 to 72 years old and the median age was 48 years old. Twenty-one tumors (57%) were located in the head of the pancreas and 16 tumors (43%) were located in body or tail of the pancreas. According to the 2000 WHO classification, there were 30 cases of well-differentiated neuroendocrine carcinomas (81%), 3 cases of poorly differentiated neuroendocrine carcinomas (8%), and 4 cases of mixed exocrine-neuroendocrine carcinomas (11%). The differences of the rate of postoperative complications and hospital stay of two groups were not statistically significant (P>0.05). The cumulative survival and disease-free survival of the extended resection group were not significantly lower than those of the non-extended resection group (P>0.05). The multivariate analysis showed that liver metastases and Ki67 were independent factors that influenced the prognosis of this disease. Conclusion For malignant advanced non-functioning PNETs with peripancreatic invasion or liver metastases, active extended surgery is a reasonable and feasible choice. Liver metastases and Ki67 are independent risk factors that influence the prognosis.

Key words: pancreatic neuroendocrine tumor, malignant tumor, surgical treatment, survival