From the Guidelines
A neuroendocrine tumor is a rare type of cancer that develops in specialized cells called neuroendocrine cells, which have traits of both nerve cells and hormone-producing cells, and can occur throughout the body but most commonly form in the digestive tract, pancreas, and lungs 1. These tumors can be either functioning or non-functioning in nature, with functioning tumors associated with clinical syndromes such as the carcinoid syndrome, and non-functioning tumors typically causing symptoms by growing and pressing on nearby organs. Some key characteristics of neuroendocrine tumors include:
- They can occur in various parts of the body, with the majority arising in gastrointestinal structures, and a smaller percentage in the bronchopulmonary system or other sites 1
- They may be functioning, producing excess hormones, or non-functioning, causing symptoms through local growth and pressure on surrounding tissues
- Treatment options vary based on the tumor's location, size, and spread, and may include surgery, medications like somatostatin analogs, targeted therapies, or peptide receptor radionuclide therapy 1
- Early detection is crucial for improving outcomes, but diagnosis can be challenging due to non-specific symptoms that may mimic other conditions 1 The behavior of neuroendocrine tumors can vary widely, from very slow-growing to aggressive, and their management often requires a multidisciplinary approach, taking into account factors such as anatomical location, tumor functionality, and histological grading 1.
From the Research
Definition of Neuroendocrine Tumors
- Neuroendocrine tumors (NETs) are a heterogeneous group of malignancies that arise from neuroendocrine cells throughout the body, most commonly originating from the lungs and gastrointestinal tract 2.
- NETs are a diverse group of neoplasms that originate from neuroendocrine cells throughout the body, with a wide range of morphologic, functional, and behavioral characteristics 3, 4.
- They can be grouped into epithelial and neural subtypes on the basis of the presence of cytokeratins or neurofilaments, respectively 4.
Characteristics of Neuroendocrine Tumors
- NETs can manifest as noninfiltrative, slow-growing tumors, locally invasive masses, or even swiftly metastasizing cancers 5.
- The biologic behavior of NETs is defined by the grade and stage of the tumor 5.
- NETs have a wide range of malignant potential, and their diagnosis depends on the recognition of characteristic morphologic features and on the presence of markers indicative of neuroendocrine differentiation 4.
Classification and Diagnosis of Neuroendocrine Tumors
- The nomenclature of NETs, particularly those of the epithelial type, remains controversial 4.
- Diagnostic terms using neuroendocrine or endocrine together with information on grading and hormonal activity provide an optimal approach for the classification of these tumors 4.
- The classification and diagnosis of NETs are complicated by several factors, including a variable natural history and nonspecific symptoms 2.
- A multidisciplinary approach to management of NETs is required to ensure a consistent and optimal level of care 2, 3.