What is neuroendocrine cancer? 1
Neuroendocrine cancer is a rare type of cancer that begins in the neuroendocrine system, the part of the body where the nervous system and the endocrine system work together.
The nervous system, which consists of the brain, spinal cord, nerves, and other key receptors, regulates, and coordinates the activities of the body. The endocrine system helps regulate and maintain various bodily functions by producing and releasing hormones into the bloodstream.
The neuroendocrine system in the human body is a diffuse and complex system of cells with different hormones. These cells can transform from normal to malignant in many different places throughout the body. Because of this, tumors are sometimes difficult to diagnose. Like other cancers, they can metastasize (spread) to other parts of the body and are life-threatening. Neuroendocrine cancer is rarely genetically inherited, and the reason for its occurrence is not understood in most cases.
Many neuroendocrine tumors secrete excessive amounts of different hormones, which can cause a variety of symptoms. While some of the tumors are unique and start at a particular site in the body, others are not.
Because the types of tumors and symptoms vary widely, treatment is based on the type of cancer that our specialists identify after a comprehensive diagnostic test.
Bloodstream markers can be used to monitor response to treatment or progression in many neuroendocrine cancers. Markers commonly followed by our clinic include chromogranin A, serotonin, catecholamine, gastrin, glucagon, insulin, growth hormone, neuron-specific enolase, VIP, C-peptide, and pancreatic polypeptide.
Types of neuroendocrine cancers
The following are the main types of neuroendocrine tumors:
- Carcinoid tumors
- Merkel cell tumors
- Neuroendocrine carcinoma
Neuroendocrine Cancer symptoms and signs2
Neuroendocrine Tumors (NET) can be discovered for many different reasons because there is no single set of common symptoms. In its early stages, NET often causes no symptoms and can only be detected during x-ray or unrelated surgery for another condition. If a person with NET has symptoms, those symptoms may be associated with the size and/or location of the tumor or with the release of hormones, such as carcinoid syndrome.
Depending on the type of NET, a person may experience the following symptoms or signs related to the tumor: General symptoms of cancer include following
- Loss of appetite
- Unexplained weight loss
- Symptoms related to the size and / or location of the tumor:
- Persistent pain in a specific area.
- Thickening or a lump anywhere on the body
- Nausea or vomiting
- Cough or hoarseness that does not go away.
- Changes in bowel or bladder habits.
- Jaundice, which is the yellowish color of the skin and the whites of the eyes.
- Unusual bleeding or discharge
- Symptoms related to the release of hormones:
- Facial redness, usually without sweating
- Hyperglycemia, which is a high level of glucose in the blood. Glucose is a sugar that the body converts into energy. Hyperglycemia causes frequent urination, increased thirst, and increased hunger.
- Hypoglycemia, which is a low level of glucose in the blood. It causes fatigue, nervousness and tremors, dizziness or light-headedness, sweating, seizures, and fainting.
- Gastric ulcerative disease
Some people also experience nutritional deficiencies before a diagnosis, such as protein and niacin deficiency. Others develop this symptom later.
Prognosis and survival for Neuroendocrine Tumors (NET) 3
If someone has a neuroendocrine tumor (NET), he/she may have questions about prognosis. A prognosis is the doctor’s best estimate of how cancer will affect someone and how they will respond to treatment. Prognosis and survival depend on many factors. Only a doctor familiar with the patient’s medical history, the type, stage, and characteristics of cancer, chosen treatments, and response to treatment can gather all of this information along with survival statistics to arrive at a prognosis.
A prognostic factor is an aspect of cancer or a personal characteristic (such as age) that the doctor will consider when making a prognosis. A predictive factor influences how cancer will respond to a certain treatment. Prognostic and predictive factors are often discussed together. Both play a role in deciding a treatment plan and prognosis.
The following are prognostic and predictive factors for NETs.
The stage of the NET is an important factor in determining the outcome. The stage includes the size of the tumor and the location of cancer in the body. Tumors found in the early stages when found have the most favorable prognosis. Tumors that are in later stages (have spread to nearby lymph nodes or other organs) have a less favorable prognosis.
The difference between tumor cells and normal cells is described as differentiation. The level of differentiation is an important prognostic factor for NETs. Well-differentiated NETs have a better prognosis than poorly differentiated neuroendocrine carcinomas.
The grade is a description of how fast NET cells grow. The degree can be determined by counting the cells that are dividing (called the mitotic count). But more often a test called the Ki-67 labeling index is used. It measures the number of cells with Ki-67 antigen in the nucleus. This is a marker that shows the increase in the number of cells due to cell growth and division. NETs with a low Ki-67 index have a more favorable prognosis and longer survival than those with a high Ki-67 index.
CgA and hormone levels
CgA (chromogranin A) and hormones are substances that can be measured to help diagnose NETs and monitor the response to treatment. People with high levels of CgA in the blood or 5-HIAA in the urine have a poorer prognosis compared to people with normal levels.
Even when any symptoms of NET are controlled, the increase in hormone levels means that cancer continues to grow (progress). For example, high levels of 5-HIAA in the urine mean there is too much serotonin and this can cause heart problems (called carcinoid heart disease). People with carcinoid heart disease have a less favorable prognosis.
People with Cushing’s syndrome also tend to have a less favorable prognosis. Cushing’s syndrome is a group of symptoms caused by too much cortisol hormone in the body.
Causes of Neuroendocrine Cancer4
The exact cause of neuroendocrine tumors is not known. These cancers start in neuroendocrine cells that have features similar to those of nerve cells and hormone-producing cells. Neuroendocrine cells are found throughout the body.
Neuroendocrine tumors start when neuroendocrine cells develop changes (mutations) in their DNA. The DNA inside a cell contains instructions that tell the cell what to do. The changes tell neuroendocrine cells to rapidly multiply and form a tumor.
Some neuroendocrine tumors grow very slowly. Others are aggressive cancers that invade and destroy normal body tissue or spread (metastasize) to other parts of the body.
The risk of neuroendocrine tumors is higher in people who inherit genetic syndromes that increase the risk of cancer. Examples include:
Multiple endocrine neoplasia, type 1 (MEN 1)
Multiple endocrine neoplasia, type 2 (MEN 2)
Von Hippel-Lindau disease