[PANCREATIC NEUROENDOCRINE TUMORS (PNET): THE DILEMMA OF SURGERY VS. WATCHFUL WAITING APPROACH]

Neuroendocrine tumors (NEN) originate from hormone producing cells located in various organs and tissues. NEN are unique tumors in terms of their diverse and particular clinical presentations, growth pattern, location and relatively good prognosis. NEN can be either secreting or non-secreting tumors. The clinical presentation and symptoms are according to the specific hormone produced by the tumor. A non-secreting tumor will eventually cause symptoms that relate to a mass-effect or a metastatic disease. There are various familial and genetic syndromes that are related to NEN. The most common neuroendocrine genetic syndrome is Multiple Endocrine Neoplasia syndrome type 1 (MEN 1). The clinical approach and treatment of NEN are unlike any other cancer. The gold standard management is surgery but unlike other cancerous diseases, surgical intervention is also indicated in cases of metastatic disease. There are several surgical approaches, and they all depend on tumor size, location, grade, stage, lymph node involvement, remote metastases and patients' age and comorbidities. Besides surgery, some cases are also treated with systemic therapies such as Somatostatin analogues, chemotherapy, immunotherapies, targeted therapies and occasionally radiation therapy is used. In the last decade there is a significant increase in the number of patients diagnosed with small non-secreting pancreatic tumors (PNET) due to advanced imaging techniques and diagnostic tools. This incidental increase is the reason for the emerging dilemma of whether to operate or merely conduct a watchful waiting policy. Small non-secreting tumors are commonly not considered malignant and thus the question is if surgery is always the right approach. The benefits of surgery must be carefully considered against the potential damage that may occur during these complex and radical procedures. Moreover, new and progressive systemic pharmacological therapies are now available to efficiently suppress tumor hormonal secretion. Recent studies have challenged surgery as the only treatment of choice, and in some cases suggest conservative treatment and follow up. The aim of this present literature review is to describe PNET diagnostic tools and evaluation, and to examine the different approaches of PNET treatment.