Cancers or tumors with an interface between the nervous system and the endocrinal system are referred to as Neuroendocrine cancers. They are also referred to as gastro-entero-pancreatic cancers.
The nervous system regulates the physiological functions of various organs through electrical impulses transmitted from the brain or the spinal cord, via the various nerves. On the other hand endocrine system comprises of glands, which release tiny dosage of hormones into the blood stream, which also act as biochemical messengers, and perform functions similar to the nervous system. A hormone is a chemical protein which carries specific information for a particular organ and is often acts on an organ remote from the organ of its origin. E.g. insulin is secreted by the pancreas, but affects the uptake by glucose by body cells, located all over the body. Similarly, thyroid gland releases thyroxin, which controls the basal metabolic rate of all the cells of the body.
The physiological functions controlled by nervous and endocrine system include metabolism, motor functions of various muscles, sensory functions, reflex functions, etc.
Neuro-endocrine system refers to a combination of both these systems and is often referred to as the GEP-NET (Gastro-Entero- Pancreatic-Neuro-Endocrinal Tumors).
Neuroendocrine cancers are typically classified into two basic categories, based on the rate at which they spread and grow. The first category comprises of carcinoid, which implies that these cancers are fairly slow growing. Carcinoids are manifested in a form of special group of symptoms often referred to as �Carcinoid Syndrome�. Estimates suggest that most of the carcinoids are detected coincidentally during an abdominal surgery and hence referred to as coincidental carcinoids.
The second category comprises of pancreatic endocrine tumors which is presumed to originate in the islet of langerhans. Pancreatic Endocrine cancers need to be differentiated from adenopancreatic cancers, as they affect the pancreas and responsible for 95% of all pancreatic cancers. On the other hand Pancreatic Endocrine cancers are responsible for just one to two percent of pancreatic tumors.
Pancreatic Endocrine cancers can be further classified into non-secretory or nonfunctional tumors or secretory or functional tumors. The non functional tumors don�t cause any major systemic damage, however the secretory or functional tumors can release excessive volumes of a hormone and cause severe systemic damage. Some examples of secretory tumors include insulinomia (i.e. excessive production of the hormone insulin), gastrinoma (i.e. excessive production of the hormone gastrin) or Glucagonoma (i.e. increased production of the hormone glucagons)