There are several different types of neuroendocrine tumors which are identified based on their location. They can appear anywhere on the body since they affect neuroendocrine cells which are widely distributed across the body. But then again, there are a few which are more common than others, especially neuroendocrine tumors along the digestive tract including the small intestines, stomach, pancreas, as well as neuroendocrine tumor in the lungs. Neuroendocrine tumors also affect regions involved with hormone production that help control your body in various aspects. Basically, this means that an endocrine tumor can also develop in glands across your body where hormones are produced. Neuroendocrine tumors can either be malignant or benign. In malignant cases, the tumors may spread to other areas of the body and even produce their own chemicals which instigate tumor-specific symptom, also referred to as carcinoid syndromes.
How Common Is Neuroendocrine Tumors Or Is It A Rare Disease?
Some of the common neuroendocrine tumors are pancreatic neuroendocrine tumors which can either be insulinomas, glucagonomas, gastrinomas, and somatostatinomas. Insulinomas are often non-cancerous and are associated with the production of insulin, Glucagonomas, on the other hand, are associated with glucagon which raises blood sugar levels, and half of them are usually cancerous. Moving on, gastrinomas produce the hormone gastrin, which helps with food digestion whereas somatostatinomas produce too much of somatostatin, which affects how the body makes other hormones. There are also VIPomas, which triggers the release of other hormones known as vasoactive internal peptides. Other common types of neuroendocrine tumors are medullary carcinoma – appears in the thyroid gland – and pheochromocytoma, which is found in the adrenal glands that sit above the kidneys.
Majority of neuroendocrine tumors occur sporadically, without a trace of inherited genetic abnormalities. Nevertheless, there are those that arise due to hereditary conditions such as multiple endocrine neoplasia type 1 with an 80-100% incidence for pancreatic neuroendocrine tumors, Von Hippen-Lindau disease with a 10-17% likelihood of pancreatic NET occurrence, tuberous sclerosis, and neurofibromatosis type 1 where up to 10% of patients develop a pancreatic neuroendocrine tumor. Old age is yet another risk factor of neuroendocrine tumors with older adults being more at risk compared to younger individuals and children. Additionally, women are more likely to develop neuroendocrine tumors than men. Females are likely to develop gastric, appendiceal, lung, and cecal-based neuroendocrine tumors and men are likely to develop pancreas, thymic, small bowel and rectal primaries-based neuroendocrine tumors.
Neuroendocrine are considered rare, or otherwise uncommon. However, there are about 3-5 incidences of the disorder in 100,000 people. In the US, 5.25 out of 100,000 people are diagnosed with a neuroendocrine tumor each year. Neuroendocrine tumors constitute the second most predominant type of gastrointestinal cancers with about 35 cases in a population of 100,000. Over the years, the incidences of neuroendocrine tumors have been on the rise, which has been attributed to greater awareness, better screening and reporting advancements associated with the condition. In cases of well-differentiated NETs, about two-thirds arise from the distal small bowel and proximal large intestines whereas one-fourth arises from the bronchopulmonary region. Additionally, a quarter of those with neuroendocrine tumors has the metastatic form of the disease.
The Prognosis Of Neuroendocrine Tumors
The prognosis of neuroendocrine tumors is dependent on the type of tumor, the location, its growth, and spread, as well as the effect it has on the body. For midgut neuroendocrine tumors such as jejunal, cecal, appendiceal and proximal colonic tumors, they are more likely to be low-grade, meaning they don’t grow fast. As a result, they are diagnosed at a late stage, which can reduce the outlook of the condition. Hindgut NETs including distal colon and rectum tumors are rarely hormonally active, meaning they don’t cause a lot of problems. Thymic form of NET is either intermediate or high-grade thus is highly lethal. In general, the 5-year survival rate for localized and metastatic midgut well-differentiated neuroendocrine tumors is 52-77% whereas the 5-year survival rate for non-metastatic midgut well-differentiated NETs is 90%.
Neuroendocrine tumors are rare and overall are complex and difficult to diagnose. This is because neuroendocrine tumors tend to grow slowly and for the longest time, patients exhibit no or very vague symptoms of the disease. Therefore, by the time the tumor is being diagnosed, it has advanced in stage and has spread to other parts of the body. The best way to manage neuroendocrine tumors is through multidisciplinary treatment plans depending on the type and location of the primary tumor.
- What Is A Low-Grade Neuroendocrine Tumor & Are Neuroendocrine Tumors Always Cancerous?
- Where Do Neuroendocrine Tumors Originate & Where Are Neuroendocrine Cells Found?