Neuroendocrine and Carcinoid Tumors

Neuroendocrine tumors (or NETs) start in neuroendocrine cells, which are nerve-like cells that also make hormones. These cells are found all over the body.

For adults, these tumors often grow in the digestive tract, mostly in the small intestine or rectum. In children and young adults, neuroendocrine tumors typically start in the appendix.

Types & Stages

There are many different types of neuroendocrine tumors. They are separated based on where the tumors are growing, how fast they are growing, and whether the tumor cells make hormones.

For example, gastrointestinal NETs grow in the digestive tract while lung NETs grow in the lungs. NETs can also grow in the pancreas, skin and thyroid.

Indolent NETs, also called carcinoid tumors, are slow growing. Carcinoid tumors don’t often spread to other parts of the body. Aggressive NETs are fast growing.

Functional NETs make hormones and release them into the bloodstream, whereas nonfunctional NETs do not.

If you are diagnosed with neuroendocrine tumors, your doctor will run tests to find out what stage it is. The stage means how big the tumor or tumors are and whether they have spread. Knowing the stage will help your doctor figure out the best treatment for you.

Signs & Symptoms

Symptoms of neuroendocrine tumors depend on where the tumor is growing and if it is making hormones.

Neuroendocrine tumors in the digestive tract can cause symptoms such as:

• abdominal pain
• diarrhea
• constipation
• blood in your stool
• redness and warmth in your face (flushing)
• fast heartbeat

Causes & Risk Factors

There are only a few things that are known to raise your risk of developing gastrointestinal neuroendocrine tumors. If MEN1 syndrome or NF1 syndrome runs in your family, your risk of developing a neuroendocrine tumor is higher. These are genetic disorders that are passed down in families.

If you have a condition that changes how much stomach acid your body makes, your risk of developing a neuroendocrine tumor is higher. Such conditions include atrophic gastritis, pernicious anemia and Zollinger-Ellison syndrome.

Not everyone with these risk factors will develop gastrointestinal neuroendocrine tumors. Sometimes people with no risk factors develop gastrointestinal neuroendocrine tumors.

Screening

There is no screening test for neuroendocrine tumors. NETs are sometimes found by accident while a doctor is testing you for another condition or issue.

Diagnosis

At Stony Brook Cancer Center, our doctors use a combination of tests to diagnose gastrointestinal neuroendocrine tumors, such as:

• Blood tests or urine tests to look for hormones that neuroendocrine tumors may release.
• Endoscopy, to look in your digestive tract. For this test, a thin, flexible tube with a small video camera on the end (an endoscope) is inserted down your throat and into your intestines.
• Colonoscopy, to look inside your large intestine (colon). For this test, a thin, flexible tube with a light and surgical tools on the end (a colonoscope) is inserted through your rectum and into your intestines.
• Imaging tests, like MRI and CT, to look inside your digestive tract.
• Biopsy, to take a sample of cells from your body and look at them under a microscope.

Treatment

Treatment for neuroendocrine tumors depends on many factors including where your tumors are growing, how fast they are growing, and whether they are making hormones.

Your treatment may include:

• Surgery to remove NETs in the digestive tract. Depending on where and how big your tumors are, surgery may be done using a thin, flexible tube with a light and surgical tool on the end (an endoscope).
• Radiation therapy. At Stony Brook Medicine, most of our radiation treatments are given with x-rays and electron beams generated by machines called linear accelerators.
• Radioactive drugs, also called radiopharmaceuticals or peptide receptor radionuclide therapy, which are drugs that deliver radiation directly to cancer cells. A radioactive drug called Lutathera slips into neuroendocrine tumors and releases a radioactive substance that kills the cancer cells. Lutathera treatment requires significant training and a high level of expertise and coordination by a multidisciplinary team. The Stony Brook Cancer Center team is proud to be able to offer this in-demand treatment to patients since 2019.
• Hormone therapy, a type of drug that stops your tumors from making extra hormones.
• Chemotherapy, a type of drug that stops the growth of cancer cells.
• Targeted therapy, which is therapy that is targeted to the genetic or molecular changes in your tumors.

At Stony Brook Medicine, our Palliative Care Service is available to everyone, no matter the stage of your cancer. This specialized team helps patients and their families cope with the physical, emotional, and spiritual distress of cancer. They can provide relief from symptoms of neuroendocrine tumors and/or their treatment, such as diarrhea, trouble breathing, and redness and warmth in your face (flushing).