Pancreatic neuroendocrine tumors.

PURPOSE OF REVIEW: Pancreatic neuroendocrine tumors (pNETs) are a rare, heterogeneous group of pancreatic neoplasms with a wide range of malignant potential. They may manifest as noninfiltrative, slow-growing tumors, locally invasive masses, or even swiftly metastasizing cancers.

RECENT FINDINGS: In recent years, because of the increasing amount of scientific literature available for pNETs, the classification, prognostic stratification criteria, and available consensus guidelines for diagnosis and therapy have been revised and updated.

SUMMARY: The vast majority of new pNET diagnoses consist of incidentally discovered lesions on cross-sectional imaging. The biologic behavior of pNETs is defined by the grade and stage of the tumor. Surgery is the only curative treatment and it, therefore, represents the first therapeutic choice for any localized pNET; however, recent evidence suggests that patients with small (<2 cm), nonfunctioning G1 tumors can be safely observed.An aggressive surgical approach towards liver metastases is recommended in selected cases, as well as liver-directed therapies for disease control. In the presence of unresectable progressive disease, somatostatin analogs, targeted therapies such as everolimus, peptide receptor radionuclide therapy, and systemic chemotherapy are all useful tools for prolonging survival.