The Diagnosis and Medical Management of Advanced Neuroendocrine Tumors

Abstract

Neuroendocrine tumors (NETs) constitute a heterogeneous group of neoplasms that originate from endocrine glands such as the pituitary, the parathyroids, and the (neuroendocrine) adrenal, as well as endocrine islets within glandular tissue (thyroid or pancreatic) and cells dispersed between exocrine cells, such as endocrine cells of the digestive (gastroenteropancreatic) and respiratory tracts. Conventionally, NETs may present with a wide variety of functional or nonfunctional endocrine syndromes and may be familial and have other associated tumors. Assessment of specific or general tumor markers offers high sensitivity in establishing the diagnosis and can also have prognostic significance. Imaging modalities include endoscopic ultrasonography, computed tomography and magnetic resonance imaging, and particularly, scintigraphy with somatostatin analogs and metaiodobenzylguanidine. Successful treatment of disseminated NETs requires a multimodal approach; radical tumor surgery may be curative but is rarely possible. Well-differentiated and slow-growing gastroenteropancreatic tumors should be treated with somatostatin analogs or alpha-interferon, with chemotherapy being reserved for poorly differentiated and progressive tumors. Therapy with radionuclides may be used for tumors exhibiting uptake to a diagnostic scan, either after surgery to eradicate microscopic residual disease or later if conventional treatment or biotherapy fails. Maintenance of the quality of life should be a priority, particularly because patients with disseminated disease may experience prolonged survival.

Gastroenteropancreatic Neuroendocrine Tumours – An Institutional Experience

“…The NETs occur 6.5-8.4 times more frequently in ileum than in duodenum and jejunum [13]. Even though primary tumour was only 2.5 cm, it had already metastasized to the liver and this is in accordance to studies conducted by Kaltsas et al [14].…”

Expression of cortistatin and MrgX2, a specific cortistatin receptor, in human neuroendocrine tissues and related tumours

“…The possibility that the parathyroid gland could produce peptide hormones other than parathormone, namely calcitonin, has been recently described [27]. The presence of SRIF receptors (particularly subtype 2) correlates with the reported positivity of some parathyroid tumours on octreotide scintigraphy [28], although the absence of any biological effect of octreotide on parathormone secretion has been reported by others [29,30]. In any case, since neither MrgX2 nor GHS-R1a was found in normal and neoplastic parathyroid tissues, the possibility that CST plays a role in regulating parathyroid function via SRIF receptor subtypes (1-3), in either physiological or pathological conditions, should be considered.…”

Pulmonary and extrapulmonary poorly differentiated large cell neuroendocrine carcinomas

“…Hormone secretion, tailored imaging (including functional imaging), and association as part of an inherited syndrome represent major features of NETs. 1 Regarding their prognostic features, pathologic differentiation has emerged as a major parameter. [2][3][4] Indeed, poorly differentiated neuroendocrine carcinomas (NECs), which are subclassified as large cell NEC (LCNEC) or small cell NEC (SCC), are characterized by a much more aggressive course than well-differentiated tumors.…”