Islet Cell Tumors (Endocrine Pancreas) (PDQ®)

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General Information About Islet Cell Tumors (Endocrine Pancreas)

The pancreas is a gland about 6 inches long that is shaped like a thin pear lying on its side. The wider end of the pancreas is called the head, the middle section is called the body, and the narrow end is called the tail. The pancreas lies behind the stomach and in front of the spine. Anatomy of the pancreas. The pancreas has three areas: head, body, and tail. It is found in the abdomen near the stomach, intestines, and other organs.

There are two kinds of cells in the pancreas:

An islet cell tumor may also be called a pancreatic endocrine tumor (PET), pancreatic neuroendocrine tumor, islet cell carcinoma, or pancreatic carcinoid.

This summary discusses islet cell tumors of the endocrine pancreas. See the PDQ summary on Pancreatic Cancer Treatment for information on exocrine pancreatic cancer.

Islet cells make and release hormones into the blood. Islet cell tumors may be functional (the hormones that are released cause symptoms) or nonfunctional (the hormones that are released do not cause symptoms) tumors:

  • Functional tumors make one or more hormones, such as gastrin, insulin, and glucagon, that cause symptoms. Most functional tumors are benign (not cancer).
  • Nonfunctional tumors make hormones that do not cause symptoms. Symptoms are caused by the tumor as it spreads and grows. Most nonfunctional tumors are malignant (cancer).

Islet cells make different kinds of hormones such as gastrin, insulin, and glucagon. Types of functional islet cell tumors include the following:

  • Gastrinoma: A tumor that forms in cells that make gastrin. Gastrin is a hormone that causes the stomach to release an acid that helps digest food. Both gastrin and stomach acid are increased by gastrinomas. When increased stomach acid, stomach ulcers, and diarrhea are caused by a tumor that makes gastrin, it is called Zollinger-Ellison syndrome. A gastrinoma usually forms in the head of the pancreas and sometimes forms in the small intestine. Most gastrinomas are malignant (cancer).
  • Insulinoma: A tumor that forms in cells that make insulin. Insulin is a hormone that controls the amount of glucose (sugar) in the blood. It moves glucose into the cells, where it can be used by the body for energy. Insulinomas are usually slow-growing tumors that rarely spread. An insulinoma forms in the head, body, or tail of the pancreas. Insulinomas are usually benign (not cancer).
  • Glucagonoma: A tumor that forms in cells that make glucagon. Glucagon is a hormone that increases the amount of glucose in the blood. It causes the liver to break down glycogen. Too much glucagon causes hyperglycemia (high blood sugar). Glucagonomas are often malignant. A glucagonoma usually forms in the tail of the pancreas. Most glucagonomas are malignant (cancer).
  • Other types of tumors: There are other rare types of functional islet cell tumors that make hormones, including hormones that control the balance of sugar, salt, and water in the body. These tumors include:
    • VIPomas, which make vasoactive intestinal peptide. VIPoma may also be called Verner-Morrison syndrome.
    • Somatostatinomas, which make somatostatin.
    These other types of tumors are grouped together because they are treated in much the same way.

Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor.

Multiple endocrine neoplasia type 1 (MEN1) syndrome is a risk factor for islet cell tumors.

Symptoms can be caused by the growth of the tumor and/or by hormones the tumor makes. Some tumors may not cause symptoms. Conditions other than islet cell tumors can cause the symptoms listed below. A doctor should be consulted if any of these problems occur.

Signs and symptoms of a non-functioning islet cell tumor

A non-functioning islet cell tumor may grow for a long time without causing symptoms. It may grow large or spread to other parts of the body before it causes symptoms, such as:

  • Diarrhea.
  • Indigestion.
  • A lump in the abdomen.
  • Pain in the abdomen or back.
  • Yellowing of the skin and whites of the eyes.

A tumor that makes pancreatic peptides (PPoma) often has no symptoms.

Signs and symptoms of a functioning islet cell tumor

The symptoms of a functioning islet tumor depend on the type of hormone being made.

Too much gastrin may cause:

  • Stomach ulcers that keep coming back.
  • Pain in the abdomen, which may spread to the back. The pain may come and go and it may go away after taking an antacid.
  • The flow of stomach contents back into the esophagus (gastroesophageal reflux).
  • Diarrhea.

Too much insulin may cause:

  • Low blood sugar. This can cause blurred vision, headache, and feeling lightheaded, tired, weak, shaky, nervous, irritable, sweaty, confused, or hungry.
  • Feeling a fast heartbeat.

Too much glucagon may cause:

  • Skin rash on the face, stomach, or legs.
  • High blood sugar. This can cause headaches, frequent urination, dry skin and mouth, or feeling hungry, thirsty, tired, or weak.
  • Blood clots in the lung. This can cause shortness of breath, cough or pain in the chest. Blood clots in the arm or leg can cause pain, swelling, warmth, or redness of the arm or leg.
  • Diarrhea.
  • Weight loss for no known reason.
  • Sore tongue or sores at the corners of the mouth.

Too much vasoactive intestinal peptide (VIP) may cause:

  • Very large amounts of watery diarrhea.
  • Dehydration. This can cause feeling thirsty, making less urine, dry skin and mouth, feeling tired, headache, or dizziness.
  • Low potassium level in the blood. This can cause muscle weakness, aching, or cramps, numbness and tingling, frequent urination, and feeling a fast heartbeat, confused, or thirsty.
  • Cramps or pain in the abdomen.
  • Weight loss for no known reason.

Too much somatostatin may cause:

  • High blood sugar. This can cause headaches, frequent urination, dry skin and mouth, or feeling hungry, thirsty, tired, or weak.
  • Diarrhea.
  • Steatorrhea (very foul-smelling stool that floats).
  • Gallstones.
  • Yellowing of the skin and whites of the eyes.
  • Weight loss for no known reason.

The following tests and procedures may be used:

  • Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
  • Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances, such as glucose (sugar), released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.
  • Serum tumor marker test: A procedure in which a sample of blood is checked to measure the amounts of certain substances released into the blood by organs, tissues, or tumor cells in the body. Certain substances are linked to specific types of cancer when found in increased levels in the blood. These are called tumor markers.
  • Immunohistochemistry study: A laboratory test in which a substance such as an antibody, dye, or radioisotope is added to a sample of cancer tissue to test for certain antigens. This type of study is used to tell the difference between different types of cancer.
  • Abdominal CT scan (CAT scan): A procedure that makes a series of detailed pictures of the abdomen, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
  • MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
  • Somatostatin receptor scintigraphy: A type of radionuclide scan that may be used to find small islet cell tumors. A small amount of radioactive octreotide (a hormone that attaches to tumors) is injected into a vein and travels through the blood. The radioactive octreotide attaches to the tumor and a special camera that detects radioactivity is used to show where the tumors are in the body. This procedure is also called octreotide scan and SRS.
  • Abdominal ultrasound: An ultrasound exam used to make pictures of the inside of the abdomen. The ultrasound transducer is pressed against the skin of the abdomen and directs high-energy sound waves (ultrasound) into the abdomen. The sound waves bounce off the internal tissues and organs and make echoes. The transducer receives the echoes and sends them to a computer, which uses the echoes to make pictures called sonograms. The picture can be printed to be looked at later.
  • Endoscopic ultrasound (EUS): A procedure in which an endoscope is inserted into the body, usually through the mouth or rectum. An endoscope is a thin, tube-like instrument with a light and a lens for viewing. A probe at the end of the endoscope is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. This procedure is also called endosonography.
  • Angiogram: A procedure to look at blood vessels and the flow of blood. A contrast dye is injected into the blood vessel. As the contrast dye moves through the blood vessel, x-rays are taken to see if there are any blockages.
  • Laparotomy: A surgical procedure in which an incision (cut) is made in the wall of the abdomen to check the inside of the abdomen for signs of disease. The size of the incision depends on the reason the laparotomy is being done. Sometimes organs are removed or tissue samples are taken and checked under a microscope for signs of disease.
  • Intraoperative ultrasound: A procedure that uses high-energy sound waves (ultrasound) to create images of internal organs or tissues during surgery. A transducer placed directly on the organ or tissue is used to make the sound waves, which create echoes. The transducer receives the echoes and sends them to a computer, which uses the echoes to make pictures called sonograms.
  • Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. There are several ways to do a biopsy for islet cell tumors. Cells may be removed using a fine or wide needle inserted into the pancreas during an x-ray or ultrasound. Tissue may also be removed during a laparoscopy (a surgical incision made in the wall of the abdomen).
  • Bone scan: A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the blood. The radioactive material collects in bones where cancer cells have spread and is detected by a scanner.

The following tests and procedures may be used:

Gastrinoma

  • Fasting serum gastrin test: A test in which a blood sample is checked to measure the amount of gastrin in the blood. This test is done after the patient has had nothing to eat or drink for at least 8 hours. Conditions other than gastrinoma can cause an increase in the amount of gastrin in the blood.
  • Gastric acid secretion test: A test to measure the amount of acid made by the stomach. A tube is inserted through the nose or throat, into the stomach. Gastrin or insulin is injected into the patient, which causes the stomach to make stomach secretions (gastric acid). Four samples of gastric acid are taken through the tube 15 minutes apart. These four samples are used to find out the lowest and highest amounts of gastric acid made during the test and the pH level of the gastric secretions.
  • Secretin stimulation test: If the gastric acid secretion test result is not normal, a secretin stimulation test may be done. The tube is moved into the small intestine and samples are taken from the small intestine after a drug called secretin is injected. Secretin causes the small intestine to make acid. When there is a gastrinoma, the secretin causes an increase in how much gastric acid is made and the level of gastrin in the blood.
  • Calcium infusion test: A test to measure the amount of gastrin in the blood after a drug called calcium gluconate is infused. Blood samples will be taken to measure the amount of gastrin in the blood at set times.
  • Somatostatin receptor scintigraphy: A type of radionuclide scan that may be used to find small islet cell tumors. A small amount of radioactive octreotide (a hormone that attaches to tumors) is injected into a vein and travels through the blood. The radioactive octreotide attaches to the tumor and a special camera that detects radioactivity is used to show where the tumors are in the body. This procedure is also called octreotide scan and SRS.

Insulinoma

  • Fasting serum glucose and insulin test: A test in which a blood sample is checked to measure the amounts of glucose (sugar) and insulin in the blood. The test is done after the patient has had nothing to eat or drink for at least 8 hours.
  • C-peptide suppression test: A test in which a blood sample is checked to measure the amount of C-peptide in the blood. Insulin is injected into a vein to lower the patient's blood sugar. This should decrease the amount of insulin and C-peptide that the body releases into the blood. In patients who have insulinoma, the insulin and C-peptide levels do not drop because the tumor is also releasing insulin and C-peptide into the blood.
  • Venous sampling after arterial stimulation: A procedure used to help find where a tumor has formed in the pancreas. This is done at the same time as an angiogram. Calcium is injected into an artery that goes to one part of the pancreas (the head, body, and tail are tested one at a time). A blood sample is taken from a vein that comes out of the pancreas and is checked for pancreatic hormones. If there is an islet cell tumor in the area of the pancreas that gets blood from the artery that was injected, there will be an increase in the amount of hormone in the blood sample. If the increase is found after injection into the first artery, the tumor is in the area that gets blood from that artery. If there is no increase, another artery is injected and the test continues.
  • Anti-insulin antibody test: A test in which a blood sample is checked to see if there are antibodies against insulin in it.

Glucagonoma

  • Fasting serum glucagon test: A test in which a blood sample is checked to measure the amount of glucagon in the blood. The test is done after the patient has had nothing to eat or drink for at least 8 hours.

Other tumor types

  • VIPoma
    • Serum VIP (vasoactive intestinal peptide) test: A test in which a blood sample is checked to measure the amount of VIP.
    • Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it. In VIPoma, there is a lower than normal amount of potassium.
    • Stool analysis: A stool sample is checked for a higher than normal sodium (salt) and potassium levels.
  • Somatostatinoma
    • Fasting serum somatostatin test: A test in which a blood sample is checked to measure the amount of somatostatin in the blood. The test is done after the patient has had nothing to eat or drink for at least 8 hours.
    • Somatostatin receptor scintigraphy: A type of radionuclide scan that may be used to find small islet cell tumors. A small amount of radioactive octreotide (a hormone that attaches to tumors) is injected into a vein and travels through the blood. The radioactive octreotide attaches to the tumor and a special camera that detects radioactivity is used to show where the tumors are in the body. This procedure is also called octreotide scan and SRS.
  • PPoma
    • Fasting serum polypeptide test: A test in which a blood sample is checked to measure the amount of pancreatic polypeptide in the blood. The test is done after the patient has had nothing to eat or drink for at least 8 hours.
    • Somatostatin receptor scintigraphy: A type of radionuclide scan that may be used to find small islet cell tumors. A small amount of radioactive octreotide (a hormone that attaches to tumors) is injected into a vein and travels through the blood. The radioactive octreotide attaches to the tumor and a special camera that detects radioactivity is used to show where the tumors are in the body. This procedure is also called octreotide scan and SRS.
    • Atropine suppression test: A test used to help find out if the secretion of a polypeptide (protein) by the pancreas is normal or caused by a tumor. A drug called atropine, which can lessen secretions, is injected into a vein. After the injection, pancreatic polypeptide levels in the blood stay the same in patients with tumors, but drop in patients without tumors.
    • Immunohistochemistry study: A laboratory test in which a substance such as an antibody, dye, or radioisotope is added to a sample of cancer tissue to test for certain antigens.

Islet cell tumors can often be cured. The prognosis (chance of recovery) and treatment options depend on the following:

  • The type of cancer cell.
  • Where the tumor is found in the pancreas.
  • Whether the tumor has spread to more than one place in the pancreas or to other parts of the body.
  • Whether the patient has MEN1 syndrome.
  • The patient's age and general health.
  • Whether the cancer has just been diagnosed or has recurred (come back).

Stages of Islet Cell Tumors (Endocrine Pancreas)

The extent or spread of cancer is usually described as stages. There is no standard staging system for islet cell cancer. The tumors are treated based on where the cancer is found:

  • The cancer is found in one place in the pancreas.
  • The cancer is found in several places in the pancreas.
  • The cancer has spread to lymph nodes near the pancreas or to other parts of the body such as the liver, lung, peritoneum, or bone.

The results of the tests and procedures used to diagnose islet cell tumors and determine whether the cancer has spread help decide the type of treatment that will be used. See the General Information section for a description of these tests and procedures.

The three ways that cancer spreads in the body are:

  • Through tissue. Cancer invades the surrounding normal tissue.
  • Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
  • Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

Recurrent Islet Cell Tumors (Endocrine Pancreas)

Recurrent islet cell tumors are tumors that have recurred (come back) after being treated. The tumors may come back in the pancreas or in other parts of the body.

Treatment Option Overview

Different types of treatments are available for patients with islet cell tumors. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

An operation may be done to remove the tumor. One of the following types of surgery may be used:

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). Combination chemotherapy is the use of more than one anticancer drug. The way the chemotherapy is given depends on the type of the cancer being treated.

Hormone therapy is a cancer treatment that removes hormones or blocks their action and stops cancer cells from growing. Hormones are substances made by glands in the body and circulated in the bloodstream. Some hormones can cause certain cancers to grow. If tests show that the cancer cells have places where hormones can attach (receptors), drugs, surgery, or radiation therapy is used to reduce the production of hormones or block them from working.

Hepatic arterial occlusion uses drugs, small particles, or other agents to block or reduce the flow of blood to the liver through the hepatic artery (the major blood vessel that carries blood to the liver). This is done to kill cancer cells growing in the liver. The tumor is prevented from getting the oxygen and nutrients it needs to grow. The liver continues to receive blood from the hepatic portal vein, which carries blood from the stomach and intestine.

Chemotherapy delivered during hepatic arterial occlusion is called chemoembolization. The anticancer drug is injected into the hepatic artery through a catheter (thin tube). The drug is mixed with the substance that blocks the artery and cuts off blood flow to the tumor. Most of the anticancer drug is trapped near the tumor and only a small amount of the drug reaches other parts of the body.

The blockage may be temporary or permanent, depending on the substance used to block the artery.

Supportive care is given to lessen the problems caused by the disease or its treatment. Supportive care for islet cell cancer may include treatment for the following:

  • Stomach ulcers may be treated with drug therapy such as:
    • Proton-pump inhibitor drugs such as omeprazole, lansoprazole, or pantoprazole.
    • Histamine blocking drugs such as cimetidine, ranitidine, or famotidine.
    • Somatostatin-type drugs such as octreotide.
  • Diarrhea may be treated with:
  • Low blood sugar may be treated by having small, frequent meals or with drug therapy to maintain a normal blood sugar level.
  • High blood sugar may be treated with drugs taken by mouth or insulin by injection.

Information about clinical trials is available from the NCI Web site.

For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.

Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.

Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.

Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.

Clinical trials are taking place in many parts of the country. See the Treatment Options section that follows for links to current treatment clinical trials. These have been retrieved from NCI's listing of clinical trials.

Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests. This is sometimes called re-staging.

Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.

Treatment Options for Islet Cell Tumors (Endocrine Pancreas)

A link to a list of current clinical trials is included for each treatment section. For some types or stages of cancer, there may not be any trials listed. Check with your doctor for clinical trials that are not listed here but may be right for you.

Gastrinoma

Treatment of gastrinoma may include supportive care and the following:

  • For symptoms caused by stomach acid, treatment may be a drug that decreases the amount of acid made by the stomach.
  • For a single tumor in the head of the pancreas:
    • Surgery to remove the tumor.
    • Surgery to cut the nerve that causes stomach cells to make acid and treatment with a drug that decreases stomach acid.
    • Surgery to remove the whole stomach.
  • For a single tumor in the body or tail of the pancreas, treatment is usually surgery to remove the body and tail of the pancreas.
  • For several tumors in the pancreas, treatment is usually surgery to remove the body and tail of the pancreas. If tumor remains after surgery, treatment may include either:
    • Surgery to cut the nerve that causes stomach cells to make acid and treatment with a drug that decreases stomach acid; or
    • Surgery to remove the whole stomach.
  • For one or more tumors in the duodenum (the part of the small intestine that connects to the stomach), treatment is usually the Whipple procedure.
  • If no tumor is found, treatment may include the following:
    • Surgery to cut the nerve that causes stomach cells to make acid and treatment with a drug that decreases stomach acid.
    • Surgery to remove the whole stomach.
  • If the cancer has spread to the liver, treatment may include:
  • If cancer has spread to other parts of the body or does not get better with surgery or drugs to decrease stomach acid, treatment may include:
  • If the cancer mostly affects the liver and the patient has severe symptoms from hormones or from the size of tumor, treatment may include:

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with gastrinoma. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

Insulinoma

Pea, peanut, walnut, and lime show tumor sizes.

Treatment of insulinoma may include the following:

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with insulinoma. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

Glucagonoma

Treatment may include the following:

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with glucagonoma. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

Other Islet Cell Tumors

Treatment of other types of islet cell tumors may include the following:

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with islet cell tumor. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

Recurrent Islet Cell Tumors

Treatment of recurrent islet cell tumors may include the following:

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with recurrent islet cell carcinoma. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

To Learn More About Islet Cell Tumors (Endocrine Pancreas)

For more information from the National Cancer Institute about islet cell tumors (endocrine pancreas), see the Islet Cell Tumors (Endocrine Pancreas) Home Page.

For general cancer information and other resources from the National Cancer Institute, see the following:



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