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Neuroendocrine Tumor (NET)

What is neuroendocrine tumor (NET)? 

Neuroendocrine tumor grows from neuroendocrine cells. Neuroendocrine cells receive and send messages through hormones to help the body function. Neuroendocrine cells are found in organs throughout the body. Neuroendocrine tumor used to be called carcinoid tumor. 

Neuroendocrine tumors often grow very slowly. In children and young adults, neuroendocrine tumors are most often found in the appendix, called appendiceal neuroendocrine tumors, or in the lungs, called bronchial tumors. In adults, neuroendocrine tumors are most often found in the digestive tract, called GI NET. This tumor may spread to other parts of the body but does so more often in adults than children. 

How common is NET?

Neuroendocrine tumor is rare in children and more common in adults. Experts think that carcinoid tumor affects 4 in 100,000 adults. Neuroendocrine tumor in children and young adults is so rare that there is little data on how many young people have it.

How is NET diagnosed?

Some people with NETs have symptoms, but others don’t. The symptoms of NETs depend on where the tumor is inside the body. 

Patients with appendiceal neuroendocrine tumors usually have symptoms of appendicitis, such as pain in the abdomen. They may be diagnosed later with carcinoid tumor if the doctor removes the appendix and finds a tumor. Patients with carcinoid tumor in other parts of the digestive tract may have symptoms such as:

  • Pain in the abdomen
  • Nausea or vomiting
  • Diarrhea

Patients with neuroendocrine tumor in the lungs may have symptoms such as:

  • Trouble breathing
  • Chest pain
  • Wheezing 
  • Coughing up blood

Sometimes these symptoms are diagnosed as pneumonia by mistake. 

In rare cases, patients with NETs may develop carcinoid syndrome. Carcinoid syndrome is a problem that develops from the tumors making hormones.  Symptoms include:

  • Feeling flushed
  • Nausea and vomiting
  • Diarrhea 

Lab Tests: If you have symptoms of neuroendocrine tumor, your doctor will order lab tests of your urine or blood to check your hormone levels.

Imaging: Your doctor will use scans such as CT and MRI to see where the tumor is and how big it is. Different types of PET scans can also help find more fast-growing neuroendocrine cancer cells. 

Biopsy: To check if the tumor is neuroendocrine tumor your doctor will do a biopsy, taking a small sample from the tumor with a needle. An expert, called a pathologist, will study cells from the sample under the microscope and run other tests to see what kind of tumor it is. 

How is NET treated?

Treatment for each person will be unique. You should go to an expert in neuroendocrine tumor treatment to decide the best approach for your tumor. You can contact MyPART for help finding experts near you.

Surgery: If you have a carcinoid tumor, you may have surgery to remove the tumor and some surrounding tissue. Surgery is the best option for treating neuroendocrine tumor and preventing it from spreading.

When the neuroendocrine tumor is large or the cancer cells have spread to other parts of the body other treatments may include:

Somatostatin analogs: Somatostatin analogs are a type of treatment that may stop your body from making too many hormones.  This may slow down the growth of the tumor when cancer cells have spread to other part of the body

Targeted therapy: Targeted therapy is a type of treatment that uses drugs that target certain genes or proteins to kill cancer cells. Neuroendocrine tumor cells have receptors on the surface of the cells called somatostatin. A type of targeted therapy called peptide receptor radionuclide therapy (PRRT) can target these cells.

Chemotherapy: is a type of treatment that uses stronger drugs to kill fasting growing cells. 

Does NET run in families?

NET does not seem to run in families. But people with a genetic condition that can run in families called multiple endocrine neoplasia type 1 (MEN1) do have a higher risk of getting neuroendocrine tumor.

How does NET form?

We do not know what causes NET to form. Scientists are always working to understand how cancer starts, but it can be hard to prove. We know that patients with a condition called multiple endocrine neoplasia type 1 (MEN1) with changes in the gene called MEN1 have a higher chance of developing bronchial and intestinal carcinoid tumor. So this gene may play a role in NETs of the lung and digestive tract. 

What is the prognosis for someone with carcinoid tumor?

The estimate of how a disease will affect you long-term is called prognosis. Each person is different and prognosis will depend on many factors, such as: 

  • Where the tumor is in your body
  • If the cancer has spread to other parts of your body
  • How much of the tumor was taken out during surgery 

If you want information on your prognosis, it is important to talk to your doctor. Also, NCI has resources to help you understand cancer prognosis

Doctors estimate NET survival rates by how groups of people with NET have done in the past. In children, because there are so few cases of NET, these rates may not be very accurate. 

The prognosis for children and young adults who have surgery to remove the tumor have a very good prognosis. Some studies show the 5-year survival rate for children and young adults with bronchial NET that has been removed is over 90%. Prognosis for people whose NET has spread to other parts of the body may be lower.