Malignant nonfunctioning endocrine tumors of the pancreas: Predictive factors for survival after surgical treatment

Background: There are scant studies that have analyzed the prognostic factors for malignant nonfunctioning endocrine tumors of the pancreas. We identified the predictive factors associated with long-term survival after surgical resection for malignant nonfunctioning endocrine tumors. Methods: Among the 25 patients seen at our hospital with a diagnosis of malignant nonfunctioning endocrine tumor, a review was performed on 22 of these patients who were surgically treated at our institution over the last 10 years. The following factors were evaluated for disease-specific mortality: age, gender, tumor location, tumor size, histological differentiation, status of the resection margin, and status of lymph node involvement. Results: Tumor recurrence was noted in 9 cases (40.9%) among the 22 operated patients. Of the 9 recurrent cases, 7 patients (77.8%) had liver metastases. The median follow-up period was 24.8 (range: 3.7-121.4) months. The overall actuarial 1-, 2- and 5-year survival rates were 84.1%, 72.5%, and 52.8%, respectively. The factor shown to have a favorable independent prognostic significance was a negative resection margin (odds ratio = 19.44, 95% confidence interval = 1.22-310.54, P = 0.036). Conclusions: Definitive surgical resection of the primary tumor was a predictor of long-term survival after surgical resection for malignant nonfunctioning endocrine tumor.