Neuroendocrine Cancer
Neuroendocrine cancers, also called NEN or NET, can be found in several organs along the GI tract. These are tumors that form in neuroendocrine cells. Many neuroendocrine cancers are slow-growing and very rare, although incidence has been increasing over the last few decades. It’s estimated that 1-2 per 100,000 people are diagnosed with NET in the GI tract each year. Oftentimes, neuroendocrine cancer is found while patients are undergoing tests or procedures for other conditions.
What is neuroendocrine cancer?
There are thousands of neuroendocrine cells in your body, and many of them line the organs of the GI tract and release hormones into your digestive system. These cells turn messages from the brain into signals that tell other organs in the body what to do. Cancer can form inside of these cells. While these cancers can form in many places throughout the body, many neuroendocrine cancers begin in the GI organs.
NET tumors in the stomach, small intestine, colon, rectum, and appendix are referred to as GI NET.
NET tumors in the pancreas are referred to as pNET or PanNET.
Carcinoid syndrome
NETs can cause carcinoid syndrome. When hormones from a NET cancer flood the liver and cannot be broken down, a patient may experience severe diarrhea, GI cramping, a flushed face and neck, wheezing, rapid heartbeat, jaundice, and swollen feet and legs. Sometimes the symptoms of carcinoid syndrome are what lead to a discovery of NET.
Staging NET cancer
Neuroendocrine tumors need to be graded and staged. The grade will determine whether the cancer is well-differentiated or poorly differentiated. This is determined by how the cells look under a microscope.
Well-differentiated
Well-differentiated cancer cells look like normal, healthy cells, and they tend to be less aggressive and slower growing. For well-differentiated cancers found in GI organs, for example the pancreas or appendix, there is a unique staging system based on the organ it was found. These staging systems will range from stage 1-4, with 4 being the most aggressive and spread to other parts of the body. These cancers are also referred to as carcinoids in the GI tract or pancreatic neuroendocrine tumors (pNETs) in the pancreas.
Poorly differentiated
Poorly differentiated cancer cells look abnormal, and they tend to be more aggressive and quicker growing. For these cancers, staging will be based on the 0-4 staging system typically used for other cancer types in that organ. These cancers are also called neuroendocrine carcinomas (NECs).
What causes neuroendocrine cancer?
Risk factors put you at a higher risk of getting cancer. Some risk factors can be controlled with lifestyle changes, and others cannot. Older age, smoking, and obesity increase your risk of many cancers.
Just because you have a risk factor, that doesn’t mean you will get cancer.
These are scenarios researchers have found that can increase your risk of getting a NET cancer.
- Hereditary syndromes like multiple endocrine neoplasia type 1 (MEN1) or type 4 (MEN4), neurofibromatosis type 1 (NF1), tuberous sclerosis complex (TSC1 or TSC2), or Von Hippel-Lindau (VHL) syndrome.
- Certain conditions like atrophic gastritis, pernicious anemia, or Zollinger-Ellison syndrome.
Preventing NET cancers
It is difficult to prevent neuroendocrine cancer, because researchers are still learning about what causes this rare cancer to form. However, patients are encouraged to follow healthy lifestyle actions to prevent cancer in general. For those at high risk, talk to a doctor about tests to stay on top of so you can detect any cancers at its earliest stages.
Learn more about cancer prevention from the American Institute for Cancer Research.
How common is neuroendocrine cancer?
Neuroendocrine cancer is classified as a rare disease, however many experts estimate approximately 8,000 cases of GI NET each year in the United States, or 1-2 in every 100,000 people.
Patients are typically between 55-65 when diagnosed. It’s found in both men and women, but women are more likely to develop NET.
What are my odds of surviving it?
Because there are so few cases, and neuroendocrine tumors can form in many areas of the body, survival rates vary. Patients with tumors in the appendix and rectum tend to do better than patients with NET in the pancreas. Smaller, well-differentiated tumors are also easier to treat than large, poorly differentiated tumors.
One study looked at the location of tumors and the extent to which they had spread to provide approximate survival rates:
Localized
The cancer hasn’t spread, usually stage 1 or 2
- 90% alive five years after diagnosis
Regional
The cancer spread to lymph nodes, usually stage 3
- 85% alive five years after diagnosis
Distant
The cancer has spread to other organs, usually stage 4
- 57% alive five years after diagnosis
What types of tests should I expect to undergo?
Neuroendocrine cancer is challenging to find, and it often has few symptoms.
Doctors may use these tests to find and diagnose NET:
- Physical exam
- Blood tests
- Urine tests
- MIBG scan
- Imaging (CT, MRI, ultrasound, PET scan)
- Endoscopy (upper and lower)
- Biopsy
Ask your doctor about these additional tests—ideally before you begin treatment.
- Biomarker testing
- Genetic testing
I’m facing a diagnosis: What are my next steps?
If you’re facing a neuroendocrine cancer diagnosis, the GI Cancers Alliance is here for you.
If you’re newly diagnosed, work with your doctor to create a treatment plan.
The grade of your NET will come into play. Cancer grades are based on a scale of 1-3, and it helps identify how slow or fast-growing the cancer is. This will help your doctors choose a treatment plan for your unique situation.
Whether the tumor is “functional” or "non-functional" will also play a role in treatment. Functional tumors secrete hormones.
Treatment plans may include:
- Surgery
- Radiation
- Chemotherapy
- Immunotherapy
- Targeted therapy
- Medicines to control hormones
We strongly encourage you to get a second opinion from another trusted doctor so you can feel confident moving forward.
