Pancreatic neuroendocrine tumors are a rare type of cancer that starts as a growth of cells in the pancreas. The pancreas is a long, flat gland that sits behind the stomach. It makes enzymes and hormones that help digest food.

Pancreatic neuroendocrine tumors start from the hormone-producing cells in the pancreas. These cells are called islet cells. Another term for pancreatic neuroendocrine tumor is islet cell cancer.

Some pancreatic neuroendocrine tumor cells keep making hormones. These are known as functional tumors. Functional tumors create too much of the given hormone. Examples of functional tumors include insulinoma, gastrinoma and glucagonoma.

Most pancreatic neuroendocrine tumors do not produce an excess amount of hormones. Tumors that don't produce extra hormones are called nonfunctional tumors.

Pancreatic neuroendocrine tumors sometimes don't cause symptoms. When they do, symptoms can include:

• Heartburn.
• Weakness.
• Fatigue.
• Muscle cramps.
• Indigestion.
• Diarrhea.
• Weight loss.
• Skin rash.
• Constipation.
• Pain in the abdomen or back.
• Yellowing of the skin and the whites of the eyes.
• Dizziness.
• Blurred vision.
• Headaches.
• Increased thirst and hunger.

When to see a doctor

Make an appointment with a health care professional if you have any symptoms that worry you.

Pancreatic neuroendocrine tumors happen when cells in the pancreas develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. The changes, which doctors call mutations, tell the cells to multiply quickly. The changes let the cells continue living when healthy cells would die as part of their natural life cycle. This causes many extra cells. The cells might form a mass called a tumor. Sometimes the cells can break away and spread to other organs, such as the liver. When cancer spreads, it's called metastatic cancer.

In pancreatic neuroendocrine tumors, the DNA changes happen in hormone-producing cells called islet cells. It's not clear what causes the changes that lead to cancer.

Factors that are associated with an increased risk of pancreatic neuroendocrine tumors include:

• A family history of pancreatic neuroendocrine tumors. If a family member was diagnosed with pancreatic neuroendocrine tumor, your risk is increased.
• Syndromes present at birth that increase the risk of tumors. Some syndromes that are passed from parents to children can increase the risk of pancreatic neuroendocrine tumors. Examples of these include multiple endocrine neoplasia, type 1 (MEN 1), von Hippel-Lindau (VHL) disease, neurofibromatosis 1 (NF1) and tuberous sclerosis. These inherited syndromes are caused by changes in the DNA. These changes allow cells to grow and divide more than needed.

There's no way to prevent pancreatic neuroendocrine tumors. If you develop this type of cancer, you didn't do anything to cause it.

Treatment for a pancreatic neuroendocrine tumor depends on the types of cells involved in your cancer, the extent and characteristics of your cancer, your preferences, and your overall health.

Options may include:

• Surgery. If the pancreatic neuroendocrine tumor is only in the pancreas, treatment usually includes surgery. For cancers in the tail of the pancreas, surgery may involve removing the tail of the pancreas, called a distal pancreatectomy. This surgery leaves the head of the pancreas intact.

  Cancers that affect the head of the pancreas may require the Whipple procedure, also called pancreaticoduodenectomy. This surgery involves removing the cancer and part or most of the pancreas.

  If the cancer spreads to other parts of the body, surgery might be an option to remove it from those locations.

• Peptide receptor radionuclide therapy, also called PRRT. PRRT combines a medicine that targets cancer cells with a small amount of a radioactive substance that's injected into a vein. The medicine sticks to the pancreatic neuroendocrine tumor cells wherever they are in the body. Over days to weeks, the medicine delivers radiation directly to the cancer cells, causing them to die.

  One PRRT, lutetium Lu 177 dotatate (Lutathera), is used to treat advanced cancers.

• Targeted therapy. Targeted therapy uses medicines that attack specific chemicals in the cancer cells. By blocking these chemicals, targeted treatments can cause cancer cells to die. Targeted therapy is used to treat certain advanced or recurrent pancreatic neuroendocrine tumors.
• Radiofrequency ablation. Radiofrequency ablation involves applying energy waves to cancer cells using a special probe with tiny electrodes. Radiofrequency ablation causes the cancer cells to heat up and die. The probe may be inserted directly in the skin or through a cut in the abdomen.
• Radiation therapy. Radiation therapy uses powerful energy beams to kill cancer cells. The energy comes from X-rays, protons or other sources. During radiation therapy, you lie on a table while a machine moves around you. The machine directs radiation to precise points on your body.
• Chemotherapy. Chemotherapy uses strong medicines to kill cancer cells. It's used in certain situations to treat pancreatic neuroendocrine tumors.

Treatment for cancer that spreads to the liver

Pancreatic neuroendocrine tumors most often spread to the liver. Several treatments exist for this, including:

• Removing part of the liver. A surgeon might remove the part of the liver that has cancer. The rest of the liver can take over for the part that's removed. In certain situations, it might be possible to remove the entire liver and replace it with a liver from a donor. This procedure is called a liver transplant.
• Slowing blood flow to the liver. Slowing blood flow through the liver's main artery, called the hepatic artery, can slow or stop cancer growth. Other blood vessels in the liver provide enough blood for the rest of the liver to keep working. Often, chemotherapy medicines or radioactive beads are used to block the artery. These methods slow the blood flow and deliver treatment directly to the cancer cells in the liver.
• Destroying cancer cells with heat. Radiofrequency ablation is a procedure that uses energy waves to heat up cancer cells and cause them to die. It's done using a special probe with tiny electrodes that's inserted through the skin and into the liver. Energy waves pass through the probe and cause the tissue around it to heat up.

With time, you'll find what helps you cope with the uncertainty and distress of a cancer diagnosis. Until then, you may find that it helps to:

• Learn enough about your cancer to make decisions about your care. Ask your health care team about your cancer, including your test results, treatment options and, if you like, your prognosis. As you learn more about cancer, you may become more confident in making treatment decisions.
• Keep friends and family close. Keeping your close relationships strong will help you deal with your cancer. Friends and family can provide the practical support you'll need, such as helping take care of your home if you're in the hospital. And they can serve as emotional support when you feel overwhelmed by cancer.

• Find someone to talk with. Find a good listener who is willing to hear you talk about your hopes and fears. This may be a friend or family member. The concern and understanding of a counselor, medical social worker, clergy member or cancer support group also may be helpful.

  Ask your health care team about support groups in your area. Other sources of information include the National Cancer Institute, the American Cancer Society, the North American Neuroendocrine Tumor Society and the Neuroendocrine Tumor Research Foundation.

Make an appointment with a health care professional if you have any symptoms that worry you. If you're diagnosed with cancer, you'll likely be referred to a specialist. Often this is a doctor who specializes in treating cancer, called an oncologist.

Here's some information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if there's anything you need to do in advance, such as fasting before having a specific test.

Gather the medical records that relate to your condition and bring them to your appointment. If you're seeing a new health care team, ask that any files and other information, such as glass slides that contain tissue samples, are sent to your new team.

Make a list of:

• Your symptoms, including any that might not seem related to the reason for your appointment.
• Key personal information, including major stresses, recent life changes and family medical history.
• All medicines, vitamins or other supplements you take, including the doses.
• Questions to ask your health care team.

Consider bringing a family member or friend to help you remember the information you're given.

For pancreatic neuroendocrine tumor, some basic questions to ask include:

• What's likely causing my symptoms?
• Other than the most likely cause, what are other possible causes for my symptoms?
• What tests do I need?
• What's the best course of action?
• What are the alternatives to the primary approach you're suggesting?
• What will happen if I don't have surgery or other medical treatments for my condition?
• I have other health conditions. How can I best manage them together?
• Are there restrictions I need to follow?
• Should I see a specialist?
• Are there brochures or other printed material I can have? What websites do you recommend?

Don't hesitate to ask other questions.

What to expect from your doctor

Be prepared to answer common questions, such as:

• When did your symptoms begin?
• Have your symptoms been continuous or occasional?
• How severe are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?
• What else should I know about you that will help me make the right recommendations about your care?