Neuroendocrine tumors (NETs) are rare and heterogenous malignancies originating from neuroendocrine cells dispersed throughout the body. In the United States, approximately 12,000 new cases of NETs are diagnosed each year, with an estimated 170,000 living patients currently. NETs account for 2% of all malignancies in the United States.
NETs can be categorized based on their anatomical location, such as gastrointestinal, pancreatic, and pulmonary sites, as well as their functional status, distinguishing between functioning and non-functioning tumors. Tumor sites include head and neck, thymus and thyroid, breast, lungs, gastrointestinal, pancreas, genitourinary tract, and skin. Clinical presentation varies significantly, with common symptoms including flushing, diarrhea, abdominal pain, weight loss, and endocrine imbalances due to increased hormone secretions impacting quality of life and prognosis.
Diagnosis typically employs a multi-modal approach, involving imaging techniques (CT, MRI, PET scans), serum biomarker assessments, and biopsy for histological confirmation. Specialized imaging, such as octreotide scans, is instrumental in identifying certain NET types.
Treatment strategies are tailored to tumor characteristics, with surgical resection being the primary intervention for localized tumors. For advanced disease, therapeutic options include somatostatin analogs, targeted therapies, and chemotherapy, while radiation therapy may be applied in select cases to alleviate symptoms.
Prognosis is highly variable, with a 5-year overall survival rate ranging from 60% to 90% depending on tumor grade and stage at diagnosis. Well-differentiated NETs generally demonstrate a more favorable outcome compared to poorly differentiated variants.