What Are GEP NE Tumors?

Gastroenteropancreatic Neuroendocrine (GEP NE) tumors are rare, generally slow-growing tumors that occur in the pancreas and the gastrointestinal tract, which includes the stomach, small intestine and large intestine. GEP NE tumors include carcinoid tumors and pancreatic endocrine tumors (also called pancreatic islet cell tumors).

Normally, neuroendocrine cells in the pancreas and the gastrointestinal system produce hormones and other potent chemicals that help regulate various functions that keep the body in working order. GEP NE tumors are thought to arise from neuroendocrine cells. When they occur, the tumors sometimes have the ability to overproduce proteins and other substances, causing a variety of symptoms throughout the body.

Statistics

Carcinoid tumors are more common than pancreatic endocrine tumors. They are found in about 1 or 2 out of 100,000 people in the United States. They occur most frequently in the appendix, small intestine, and rectum. These tumors tend to grow slowly; in fact, many people are believed to have tiny carcinoids that never cause any health problems. Nevertheless, because it is not possible to distinguish such noncancerous (benign) carcinoids from potentially cancerous (malignant) ones, all discovered carcinoid tumors should be treated as having malignant potential.

Pancreatic endocrine tumors are found in about 4 out of every 1 million people. A number of different pancreatic endocrine tumors have been described. The most commonly occurring types include:

• Insulinomas: These tumors are found most often in people between 30 and 60 years of age. They occur slightly more frequently in women. Patients with an insulinoma commonly come to medical attention because of symptoms of hypoglycemia.
• Gastrinomas: These tumors are found most frequently in people between the ages of 45 and 50. They are somewhat more common in men than in women. Gastrinomas may be found either within the pancreas itself or in an area immediately adjacent to the pancreas. Patients with gastrinoma typically have symptoms of acid hypersecretion.
• VIPomas: These tumors secrete a substance called vasoactive intestinal peptide that can cause profound diarrhea.
• PPomas: These tumors are also called nonfunctioning pancreatic endocrine tumors. They do not secrete specific hormones but can be detected through their production of a protein called pancreatic polypeptide.
• Glucagonomas: These tumors are less common than other pancreatic endocrine tumors. Patients with glucagonomas often have higher than normal blood sugars and are often diagnosed with diabetes. A rash is another common symptom of glucagonomas.

Risk Factors

Certain conditions that run in families can increase a person's risk of developing a GEP NE tumor. One genetic condition associated with pancreatic endocrine tumors is Multiple Endocrine Neoplasia type I (MEN1), a rare genetic inherited disorder linked to tumors in the pancreas and the parathyroid and pituitary glands. About 20% of gastrinomas and 7% to 8% of insulinomas are associated with MEN1. Genetic tests are available to detect mutations in the gene, MEN1, which are implicated in this disease.

Conditions that affect the production of stomach acid, such as Zollinger-Ellison syndrome, gastritis and pernicious anemia, can also increase the risk of developing gastric carcinoid tumors.

Screening

Unfortunately there is no general screening test to check for GEP NE tumors. However, the earlier a tumor is discovered, the better is a person's chance of survival. For this reason, people who notice symptoms of GEP NE tumors should discuss them with their doctor right away.

 

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