What Are Neuroendocrine Tumors?

Neuroendocrine tumors are potentially cancerous growths that originate in neuroendocrine cells. The latter are specialized cells that support both the nervous and hormone-producing endocrine systems. Because neuroendocrine cells are distributed among organs throughout the body, neuroendocrine tumors can appear in a wide range of locations. The most common sites include the lungs, the digestive tract, the pancreas, and the adrenal gland. Neuroendocrine tumors can be malignant or benign. Those that metastasize (spread) to other sites in the body pose the greatest health risk.

There multiple types of neuroendocrine tumors but most can be assigned to one of three categories:

• Carcinoid tumors: Carcinoid tumors are slow-growing cancers that usually develop in the lungs or the digestive system.
• Pancreatic or islet cell tumors: These are neuroendocrine tumors that occur on or inside the pancreas.
• Pheochromocytomas: A rare type of neuroendocrine tumor that forms on the adrenal gland. These tumors are often benign. 

If you are concerned about the possibility of a neuroendocrine tumor, arrange to see your Baptist Health family physician or oncologist.

What Are the Symptoms of a Neuroendocrine Tumor?

Neuroendocrine tumors can be difficult to detect. They don’t always present symptoms and, when they do, they vary to some degree based on the size and location of the tumor, whether or not it’s spread, the individual patient’s overall health, and other factors.

Below are indicators of a possible neuroendocrine tumor. Some of these result from abnormally high levels of hormone production, which is characteristic of this type of cancer:

• Unusual lumps, swollen glands, or thickened skin
• Coughing, wheezing, or shortness of breath
• Nausea and vomiting
• Dizziness or “the shakes”
• Excessive thirst
• Diarrhea
• Unexpected fluctuations in weight
• Persistent pain in one or more areas of the body
• High or low blood sugar
• Changes in bowel or bladder habits
• Unusual bleeding or discharge
• Headaches, fevers, or night sweats
• Anxiety
• Fatigue or weakness
• Changes in skin color (jaundice, flushing, or streaking).

What Causes a Neuroendocrine Tumor?

Like other cancers, neuroendocrine tumors result from DNA mutations that drive changes in cell behavior. Cancer cells live longer and reproduce more rapidly than healthy cells, leading to the buildup of cancerous masses or tumors that interrupt normal bodily functions. Cancer cells also metastasize or spread, extending the range and degree of disease. Medical researchers have yet to determine the exact cause or causes of the mutations.

There is evidence that genes plays a role in some neuroendocrine tumors. There are several heritable disorders that increase the likelihood of developing this type of cancer:

• Multiple endocrine neoplasia 1 (MEN1)
• Multiple endocrine neoplasia 2 (MEN2)
• Neurofibromatosis
• Tuberous sclerosis
• Von Hippel-Lindau disease.

How Is a Neuroendocrine Tumor Diagnosed?

The diagnosis of a neuroendocrine tumor typically requires a number of tests and procedures:

• Physical exam: Your doctor will examine you for evidence of cancer. He or she will document your symptoms and ask questions about your medical history and possible risk factors.
• Urine test: A urine test will provide evidence of a neuroendocrine tumor by identifying the chemical remnants of excessive hormone production.
• Blood test: If the bloodstream contains unusually high levels of certain hormones, they can be detected in blood-sample analyses. 
• Medical imaging: X-rays, CT scans, magnetic resonance imaging (MRI), and positron emission tomography (PET) scans can help your physician locate a neuroendocrine tumor. 
• Endoscopy: Endoscopes are long, slender tubes with optical elements and cameras that physicians use for close inspection of possible tumor sites, including the lungs, the digestive tract, and others. 
• Biopsy: To confirm the presence of cancer, your physician will collect a tissue sample for analysis. This sample is called a biopsy. The sample will be removed either before or during surgery, and sent to a medical laboratory for analysis.

How Is a Neuroendocrine Tumor Treated?

How a neuroendocrine tumor is treated depends on a number of variables, including its size and location, whether it has spread to other parts of the body, and the role it’s playing in hormone production. The primary methods of treatment include:

• Surgery: The surgical removal of a neuroendocrine tumor can be effective in the early stages of the disease. Surgery may be combined with other forms of cancer treatment, including radiation, chemo, targeted, and immune-system therapies.
• Targeted-radiation medications: More serious cases might call for peptide receptor radionuclide therapy (PRRT), an anticancer medication that pairs a radioactive agent with a chemical that targets cancer cells. Neuroendocrine tumors have responded to a PRRT drug called lutetium Lu 177 dotatate.