What Is Neuroendocrine tumor ( NET )
The neuroendocrine tumor (NET) begins in the specialized cells of
neuroendocrine system. These cells have traits of both the hormone-producing
endocrine cells and nerve cells. They are found throughout the body’s organs
and help to control many of the body’s functions.
All NETs are malignant tumors mostly they grow slowly whereas some NETs are
fast growing
Neuroendocrine tumor can be found in any parts
including
Lungs
GIT
Pancreas
Classification Of NETs
NETs may be classified in
various ways, including
1) by where they are located,
2) what the tumor cells look like under a microscope, and
3) how fast the cells are growing and dividing.
Classification as “functional” or “non-functional.”
- In Functional NETs there is a production and release of hormones and different substances that cause symptoms.
Carcinoid syndrome is one sign of a “functional” NET in which a substance called serotonin is released that can cause diarrhea and facial flushing.
- Non-functional NETs either does not release any substances or don’t release enough substances to cause symptoms.
About 60% of NETs are non-functional. Because of a lack of symptoms
Diagnosis
During an x-rays or a medical procedure most NETs are found unexpectedly In addition,
the Following tests may be used to diagnose a NET:
Biopsy
Blood /Urine test
Molecular testing of tumor
Endoscopy
Ultrasound
Xray
CTscan
MRI
Nuclear medicine imaging
Octreoscan
PET Scan
GRADES
Grade or degree of differentiation is how fast the tumor cells are growing and dividing.
There are mainly 3 Grades to diagnose
Grade 1 (Low Grade Tumor): Here cells divide at a slow rate and therefore grow slowly.
Grade 2 (Intermediate Grade Tumor): Here cells divide at an intermediate rate.
Grade 3 (High Grade Tumor): Here cells divide at a fast rate and therefore grow quickly.
Degree Of Differentiation.
Grade also describes how much cancer cells look like healthy cells when visualize under a microscope called degree of differentiation.
- Well differentiated: Well differentiated cells looks more like healthy cells.
- Poorly differentiated: Poorly differentiated cells looks less like healthy cells.
Grading is the measurements of how fast mitosis is happening and mitosis is the main division of tumor cells and make it grow and spread.
To measure mitosis division, doctors counts the number of dividing cells seen in 10 high-power fields under a microscope This is called the mitotic count.
Treatment
Surgery
Surgery is the removal of the tumor and some surrounding healthy tissue during an operation. A surgical oncologist is a doctor who specializes in cancer surgery.
A complete removal of the tumor is not possible, Debulking surgery is sometimes recommended.
Debulking surgery removes as much of the tumor as possible and it may
provide some relief from symptoms but it does not cure a NET.
Therapy using medicine
Systemic therapy is the use of medication to destroy cancer cells. Common ways to give systemic therapies include
- An intravenous (IV) tube placed into a vein using a needle
- A pill or capsule that is swallowed (orally),
- And intramuscular (IM) injections.
Depending on the various type of NET, therapies that may be used include:
- Somatostatin analogs
- Chemotherapy
- Targeted therapy
- Immunotherapy
- Peptide receptor radionuclide therapy (PRRT)
Somatostatin analogs
Somatostatin is a hormone that controls the release of several other hormones, such as insulin and glucagon. Somatostatin analogs are drugs that are similar to somatostatin so they are used to control the symptoms caused by the hormones-like substances released by a NET. It may also slow the growth of a NET but they do not generally shrink the tumors.
There are 2 somatostatin analogs used to treat NETs,
- octreotide (Sandostatin) and
- lanreotide (Somatuline Depot)
Octreotide
Octreotide is available in 2 forms
- short-acting is given under the skin (subcutaneously) and
- long-acting is given as an intramuscular (IM) injection.
Lanreotide
It is given as a long-acting subcutaneous injection. The most common side effects are
- high blood sugars,
- the development of gallstones,
- and mild digestive system upset, such as bloating and nausea.
Chemotherapy
Chemotherapy is the use of drugs to destroy cancer cells, usually by preventing the cancer cells from dividing, growing, and making more cells.
For NET Chemotherapy may be used when the tumor has spread from where it started to other organs, if the tumor is causing severe symptoms, or if hormonal or targeted therapies are no longer working. Chemotherapy may be used alone or in combination with other treatments.
Immunotherapy
Immunotherapy is also called biologic therapy and it is designed to boost the body’s natural defenses to fight the tumor. It uses materials made either by the body or in a laboratory to improve, target, or restore immune system function.
Interferon alfa-2b (Intron A) is a type of
immunotherapy that is used to treat NETs. Interferon helps the body’s immune
system to work better and can lessen diarrhea and flushing. It may also shrink
tumors.
Radiation therapy
It is the use of high-energy x-rays or other particles to destroy tumor cells. The radiation therapy regimen, or schedule, usually consists of a specific number of treatments given over a set period of time. A doctor who specializes in giving radiation therapy to treat cancer is called a radiation oncologist.
The most common type of radiation treatment for a NET is called External-beam radiation therapy, which is radiation given from a machine outside the body. It is most often used as part of supportive care to relieve symptoms, such as pain, caused by cancer that has spread to the bone and other areas of the body.
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