Neuroendocrine tumors (NETs) are a group of neoplasms that develop from specialized cells called neuroendocrine cells. These cells are distributed throughout the body and play a crucial role in hormone production and in the regulation of various bodily functions. When these cells undergo neoplastic transformation, they can give rise to tumors with very diverse characteristics and behaviors. NETs are characterized by their potential to secrete hormones and other substances, which can lead to a wide variety of clinical syndromes. Unlike other types of cancer, NETs usually grow more slowly (although in some subtypes growth is rapid), which can make early detection difficult.
Symptoms of neuroendocrine tumors
The symptoms of neuroendocrine tumors (NETs) vary considerably depending on the location of the tumor, its size, and the hormones it produces. Due to this variability, diagnosis can be a challenge. However, being aware of the most common symptoms can facilitate early detection and the start of treatment. Some of the most common symptoms include:
Skin redness (flushing).
Persistent diarrhea.
Abdominal pain.
Unexplained weight loss.
Fatigue and weakness.
Excessive sweating.
Changes in blood sugar levels.
It is important to note that these symptoms can be caused by other conditions, so it is essential to consult a doctor to obtain an accurate diagnosis.
Classification of neuroendocrine tumors
The classification of NETs is a complex process that helps doctors determine the best treatment approach. NETs are classified based on several factors, including:
Location: NETs can originate in different parts of the body, the most common being those of the gastrointestinal tract (stomach, small intestine, colon) and the pancreas. Within the gastrointestinal tract, they can be found in the small intestine (jejunum and ileum), appendix, colon, and rectum. They can also originate in the lung, thymus, stomach, first portion of the duodenum, thyroid gland, parathyroid gland, adrenal gland, pituitary gland, and neural crest.
Grade: the grade is based on the appearance of the tumor cells under a microscope and how quickly they are dividing. NETs are classified as low grade (grade 1 and 2) and high grade (grade 3).
Functionality: NETs can be functioning (they produce hormones that cause symptoms) or non-functioning (they do not produce hormones, or they produce hormones without causing symptoms). Functioning NETs can secrete various hormones, such as insulin (insulinoma), gastrin (gastrinoma), glucagon (glucagonoma), vasoactive intestinal peptide (VIPoma), and somatostatin (somatostatinoma).
Causes and risk factors of neuroendocrine tumors
Despite advances in research, the exact causes of NETs are still not fully understood. It is believed that a combination of genetic, hormonal, and environmental factors contributes to the development of the disease.
Although most neuroendocrine tumors (NETs) are sporadic, some risk factors can increase the likelihood of developing these tumors. Identifying these factors can help to better understand the individual risk and take preventive measures. Some of these include:
Hereditary syndromes: some NETs are associated with hereditary syndromes, such as multiple endocrine neoplasia type 1 (MEN1), caused by mutations in the MEN1 gene, which encodes menin, a tumor suppressor protein. Other syndromes include Von Hippel-Lindau disease (VHL), neurofibromatosis type 1 (NF1), and tuberous sclerosis complex (TSC).
Hormonal factors: prolonged exposure to certain hormones, such as insulin-like growth factor 1 (IGF-1), may increase the risk of developing NETs.
Genetic factors: mutations in genes such as DAXX and ATRX have been identified in pancreatic neuroendocrine tumors (NETs), which may influence tumor aggressiveness.
Environmental factors: smoking and exposure to certain chemicals have been associated with an increased risk of NETs.
If left untreated, NETs can lead to various complications that affect the health and quality of life of patients. It is crucial to be aware of these complications in order to seek timely medical attention. Some of the most common complications include:
Carcinoid syndrome: a set of symptoms caused by the release of hormones, including flushing, diarrhea, and difficulty breathing.
Intestinal obstruction: tumors can grow and block the intestine.
Metastasis: NETs can spread to other parts of the body, such as the liver, lungs, and bones.
Diagnosis of neuroendocrine tumors
An accurate and early diagnosis is essential for effective treatment. The diagnostic process of NETs generally involves a combination of tests and procedures. The diagnostic process generally includes:
Medical history review and physical examination: the doctor will ask about symptoms and perform a physical exam to look for signs of the disease.
Blood and urine tests: these tests can measure the levels of hormones and other substances produced by NETs.
Imaging tests: various techniques are used to visualize the tumor and determine its extent. Computed tomography (CT) is used to obtain detailed images of the inside of the body and detect the presence of tumors and metastases. In turn, magnetic resonance imaging (MRI) provides even more detailed images and can be useful for assessing the extent of the tumor. Octreotide scintigraphy (OctreoScan) uses a radioactive substance to detect neuroendocrine tumor cells in the body. 18F-FDG positron emission tomography (PET) can be useful for detecting high-grade tumors and for evaluating the response to treatment, while 68Ga-DOTATATE positron emission tomography (PET) is highly sensitive for characterizing low-grade tumors.
Biopsy: a tissue sample is extracted for examination under a microscope to confirm the diagnosis.
Treatment of neuroendocrine tumors
The treatment of NETs is individualized based on the stage of the cancer, the grade, the patient’s age, overall health, and personal preferences. Treatment options include:
Surgery: surgical removal of the tumor is the main treatment for localized NETs. The type of surgery depends on the location and size of the tumor, as well as the presence of metastases. Local resections, segmental resections, or more extensive procedures such as pancreaticoduodenectomy (PD) can be performed. At HM Hospitales, we have surgeons with expertise in various surgical techniques, including minimally invasive surgery and robotic surgery using the Da Vinci system.
Somatostatin analogue therapy: these drugs help control symptoms caused by hormone production and can slow tumor growth. Long-acting analogues such as octreotide LAR and lanreotide autogel are used.
Targeted therapy: these drugs block tumor growth by targeting specific molecules involved in tumor development. mTOR inhibitors such as everolimus and tyrosine kinase inhibitors such as sunitinib are used.
Radionuclide therapy: it uses radioactive substances to destroy tumor cells. Lutetium-177 DOTATATE is used, which binds to somatostatin receptors on tumor cells.
Chemotherapy: it is used to treat high-grade NETs and to reduce the size of tumors and control their growth. Regimens such as cisplatin and etoposide, or temozolomide and capecitabine are used.
Liver transplant: in selected cases of liver metastases, liver transplantation may be an option.
A multidisciplinary approach, involving surgeons, oncologists, endocrinologists, and other specialists is essential for comprehensive and personalized treatment.
Remember that this article is for informational purposes only and does not replace professional medical advice. If you suspect you have a neuroendocrine tumor, consult a specialist to obtain an accurate diagnosis and an appropriate treatment plan tailored to your needs. s un tumor neuroendocrino, consulta con un especialista para obtener un diagnóstico preciso y un plan de tratamiento adecuado a tus necesidades.
Our doctors
Contact and make an appointment with the professionals in this area
