Insulinomas versus non-functioning neuroendocrine pancreatic tumors: aspects of diagnosis and outcome after pancreatic resection

Abstract

Background: Pancreatic neuroendocrine tumors (PNET) are rare neoplasms with various subtypes. Nonfunctioning tumors are usually incidental with increased incidence in the last decades. Insulinomas are the most frequent functional tumors that present benign behavior in up to 90% of cases. We aimed to evaluate aspects of diagnosis and results of pancreatic resection of nonfunctioning (NF) tumors compared to insulinomas. Methods: We retrospectively evaluated the medical records and electronic data from 103 patients submitted to pancreatic resection at our Institutuion. Patients with small liver metastasis resected during the same surgery were included. Results: Thirty-four patients had NF pancreatic tumors and 69 insulinomas, 56% were women with 44.51 AE 17.27 years. Age was decreased and BMI increased in Insulinoma group compared to NF (p < 0.05). Enucleation was performed in 44.93% of insulinomas and pancreatoduodenectomy in 50.0% of NF tumors (p < 0.001). Tumor diameter was greater in NF group (p < 0.0001) with a trend to present positive lymphnodes (p = 0.0843). Insulinoma group showed higher number of patients with postoperative complications (p = 0.0025). Follow-up time was 7.71 AE 6.39 years in NF and 14.0 AE 10.52 years in Insulinoma (p = 0.0038). The 10-year actuarial survival was 94.95% in Insulinoma and 83.32% in NF group, without significance. Conclusions: Nonfunctioning tumors are diagnosed later than insulinomas showing greater size at surgery, however there was no significant difference in survival between these two groups of patients. Interestingly resection of insulinomas was associated with more complications, probably related to high incidence of pancreatic fistulae after tumor enucleation.