Neoadjuvant therapy for advanced pancreatic neuroendocrine tumors: an emerging treatment modality?

OBJECTIVE: Complete surgical resection is the only potentially curative treatment of localized pancreatic neuroendocrine tumors. Unfortunately, a significant proportion of these patients present with unresectable locally advanced tumors or massive metastatic disease. Recently, a new therapeutic approach for this subset of patients has emerged consisting of neoadjuvant therapy followed by surgical exploration in responders. DESIGN: We searched MEDLINE for the purpose of identifying reports regarding neoadjuvant treatment modalities for advanced pancreatic neuroendocrine tumors. RESULTS: We identified 12 studies, the vast majority of which were either case reports or small case series. Treatment options included chemotherapy, radiotherapy, peptide receptor radionuclide therapy, biological agents or various combinations of them. CONCLUSIONS: Increasing evidence supports the application of neoadjuvant protocols in advanced pancreatic neuroendocrine tumors aiming at tumor downsizing, thus rendering curative resection feasible. Given that prospective and controlled randomized clinical trials from high-volume institutions are not feasible, expert panel consensus is needed to define the optimal treatment algorithm.