About Gastrointestinal Neuroendocrine Tumors
Gastrointestinal neuroendocrine tumors (GI NETs) are caused by a change (mutation) in neuroendocrine cells in the gastrointestinal tract. The change enables the cells to survive longer than typical cells and eventually form a mass. The exact cause of the change in neuroendocrine cells that leads to GI NETs are not well understood. Several factors have been identified as potential contributors:
Non-modifiable risk factors (factors a person cannot change or control) for GI NETs include:
- Age: Older adults are more likely to develop GI NETs than younger adults or children. It is most often diagnosed in people between 55 to 65 years old.
- Sex assigned at birth: Females are slightly more likely to develop GI NETs than males.
- Family history: Having a family history of multiple endocrine neoplasia type 1 (MEN1) syndrome or neurofibromatosis type 1 (NF1) syndrome can increase the risk of developing GI NETs. These syndromes are caused by genetic mutations.
Modifiable risk factors (factors a person can potentially change or control) for GI NETs include:
- Stomach conditions: Certain conditions that affect the stomach's ability to make stomach acid, such as atrophic gastritis, pernicious anemia, or Zollinger-Ellison syndrome, can increase the risk of GI NETs, specifically in the stomach.
It's important to note that while these risk factors may increase the likelihood of developing GI NETs, they do not guarantee the development of the condition. Regular screenings and early detection can help in managing and treating GI NETs effectively. Consult with your healthcare professional to understand your individual risk factors and appropriate preventive measures.
Many people with GI NETs do not experience symptoms. When symptoms of GI NETs occur, they may not be specific and can vary depending on the location of the tumor. Some common symptoms include:
- Stomach or abdominal pain
- Diarrhea
- Change in stool color
- Nausea and vomiting
- Constipation
- Heartburn
- Signs of intestinal bleeding, like bright red blood in stool or dark-colored, tarry stool
- Fatigue (feeling exhausted)
As GI NETs progress, additional symptoms may include:
- Weight loss for no known reason
- Feeling bloated
- Jaundice (yellowing of the skin and eyes)
- Hemorrhage from multiple and recurrent peptic ulcers
- Gastroesophageal reflux caused by excess acid production
It's important to note that these symptoms can also be caused by other conditions, so it's essential to consult with a healthcare professional for an accurate diagnosis. They can evaluate your symptoms, perform tests, and recommend appropriate treatment options.
To diagnose GI NETs, the following examinations, tests, and procedures are commonly performed:
- Health history: Your doctor will ask about your symptoms and personal and family health history to gather relevant information.
- Physical exam: A comprehensive assessment of your body to check for any signs of disease or abnormalities.
- Blood chemistry studies: This involves analyzing a blood sample to measure the levels of certain substances, such as hormones, which can indicate the presence of neuroendocrine tumors.
- Tumor marker test: A sample of blood, urine, or tissue is checked to measure the levels of specific substances, such as chromogranin A, which is associated with neuroendocrine tumors.
- 24-hour urine test: Collection of urine over a 24-hour period to measure the levels of substances like 5-HIAA or serotonin, which can be indicators of neuroendocrine tumors.
- Imaging studies: Techniques such as CT scans (computed tomography) and MRI (magnetic resonance imaging) can create detailed images of organs and bones inside the body to look for GI NETs. A positron emission tomography (PET) scan is another imaging test that can specifically detect cancer cells, including neuroendocrine tumor cells. There are additional specialized radionuclide scans (scans that use small amounts of radioactivity) that may be used.
- Endoscopy: A thin tube with a camera and light is inserted through the mouth to view the upper digestive system to look for GI NET or other abnormalities that may be causing symptoms. The doctor can take a tissue sample (biopsy) during this procedure for testing.
- Colonoscopy: A thin tube with a camera and light is inserted through the rectum to view the lower part of the digestive system (the colon or large intestine) to look for GI NET or other abnormalities. The doctor can take a tissue sample (biopsy) during this procedure for testing.
Additional specialized tests and procedures may be performed based upon initial findings, individual factors, and location of the GI NET.
After diagnosis, the healthcare team will determine the stage of the GI NET. The stage is an important consideration for determining treatment options. The stage definitions differ based upon the part of the gastrointestinal tract with GI NET. Generally, staging includes consideration of:
- Tumor size
- Spread to other parts of the body outside of the gastrointestinal tract, such as to the liver or lymph nodes
- Symptoms of more advanced disease, such as carcinoid syndrome or carcinoid heart syndrome
Remember that these are general procedures and may vary depending on individual cases. It's important to consult with your healthcare professional for personalized advice.
The goals of treatment for GI NETs depend on the stage and location of the tumor.
In some cases of slow growing tumors that aren’t causing symptoms, the healthcare provider may recommend not starting treatment and performing active surveillance (“watchful waiting”). Active surveillance means the healthcare team will carefully monitor your condition through regular physical check-ups, blood tests, and imaging tests. Treatment may be started if symptoms arise, or the GI NET is growing more rapidly.
For treatment, overall goals and treatment options include:
- Remove the tumor: Surgery, known as resection, is often performed to remove the tumor and any nearby lymph nodes or organs affected by the cancer. This helps to eliminate or reduce the size of the tumor.
- Slow disease progression: In cases where complete removal of the tumor is not possible, treatments may include:
- Chemotherapy: Use of drugs to kill cancer cells
- Targeted therapy: Use of drugs or other substances to attack cancer cells and disrupt their function without affecting healthy cells
- Immunotherapy: Use of drugs or other substances to boost the body’s immune system to recognize and attack cancer cells
- Radiation therapy: Use of beams of energy to kill cancer cells or slow their growth
- Somatostatin analogs: This is a type of hormone therapy to help reduce the number of hormones produced by the body, including by GI NET tumors.
- For GI NET that has spread to the liver, liver-directed therapies to slow down growth or further spread of cancer may include:
- Embolization
- Cryosurgery
- Radiofrequency ablation
- Liver transplan.
- Relieve symptoms: For advanced or metastatic GI NETs, treatment focuses on palliative care to alleviate symptoms and improve quality of life. This may involve hormone therapy, radiopharmaceutical therapy, external radiation therapy for bone, brain, or spinal cord metastases, or participation in clinical trials for new treatments.
- Manage associated conditions: For patients with GI NETs in specific locations (such as stomach tumors in patients with MEN1 syndrome), additional surgeries may be recommended to remove tumors in other parts of the digestive system.
It's important to note this is general information about treatment of GI NETs. Specific procedures, therapies, and medications will depend on the location of GI NET, cancer stage, and individual factors. Always consult with a healthcare professional experienced in the management of GI NET for personalized treatment recommendations.
Medication dosing may be affected by many factors. Check with your health care professional about dosing for your individual situation.Side effects can occur. Check with your health care professional or read the information provided with your medication for additional side effect information.