Among the different neuroendocrine tumors of the pancreas, there are some varieties that can be treated and even cured successfully.
The tumors that appear in the islets can be functional (they produce one or more hormones) or non-functional.
Most of functional tumors that produce hormones are benign; however, 90% of non-functional tumors are malignant. Many of the islet cancer are non-functional and produce symptoms due to the tumor mass or metastatic dissemination. Due to the presence of several cell types in the pancreatic islets (alpha, beta, delta, A, B, C, D, E), the term “tumor” in this context can refer to at least five different types of cancer. In case they are functional, these have very specific clinic and metabolic characteristics. Clinic manifestations in functional tumors can be caused by the metabolic effects of the polypeptides segregated rather than the tumor mass or the metastatic disease. Because of this, each type of tumor must be considered separately in terms of diagnose and therapy. Sometimes, the functional tumors can be so small that the conventional imaging techniques cannot detect them. In such cases, high definition radiological scans, both isotopic and eco-endoscopic, are very helpful in the location of the injury.
The neuroendocrine pancreatic tumors are: glucagonoma, insulinoma, somatostatinoma, gastrinoma, vasoactive intestinal polypeptide and carcinoid.
The long delays between the first symptoms and the diagnose are frequent, and the variety of effects of the segregated polypeptides require the participation of different surgical and medical specialties in their treatment and diagnose. Surgery can be the only curing modality, with different techniques (enucleation, corporocaudal or central cephalic pancreatectomy) depending on the number, location, and tumor type. Even in cases not resectable for curation, an effective palliation can be obtained due to the slow-growing nature of these tumors and the possibility of antihormone pharmacologic therapies. Combination chemotherapy can provide an effective palliation as well as a higher level of survival in certain patients.
The best therapy for patients with secondary tumors in the islets of an indolent and slow-growing type can be chemotherapy and an ablative treatment of the dominant metastatic injuries in the liver (radiofrequency, radiosurgery and/or chemoembolization)..
In very specific cases, the liver transplant after resection of the primary injury can be a good therapeutic option, especially if there is a dominant liver disease and important symptoms caused by the tumor size or by the hormone secretion syndrome.
Patients with multiple endocrine neoplasia type 1 syndrome (an autosomal dominant condition in which 85% of patients have pancreatic tumors in the islets, 90% have hyperparathyroidism, and 65% have pituitary tumors) have less possibilities of recovery with pancreatectomy than those patients with sporadic tumors in islet cells. Radiotherapy does not play an important role in this case, except for the relief from pain caused by bone metastasis.