What are indolamine (serotonin) tumors?

From the Guidelines

Indolamine tumors, also known as carcinoid tumors or neuroendocrine tumors (NETs), should be managed with a multidisciplinary approach, prioritizing surgical removal for localized disease and somatostatin analogs for metastatic disease, to improve quality of life and reduce morbidity and mortality. These tumors are rare growths that develop from cells producing serotonin and other indolamine compounds, most frequently occurring in the gastrointestinal tract, lungs, pancreas, and other organs. Diagnosis involves blood and urine tests for serotonin metabolites like 5-HIAA, along with imaging studies such as CT scans, MRIs, or specialized nuclear medicine scans like octreotide scans 1. Key considerations in management include:

• Tumor location, size, and spread
• Surgical removal as the primary approach for localized disease
• Somatostatin analogs like octreotide or lanreotide for metastatic disease to control symptoms and slow tumor growth
• Potential for carcinoid syndrome, characterized by flushing, diarrhea, wheezing, and heart valve damage, which can be prevented, aborted, or treated with IV octreotide acetate 1. The specificity of the urinary 5-HIAA test is close to 90% 1, and serum NET biomarkers like chromogranin A should be measured, as an elevated level occurs in 75% of carcinoid tumors and 60% of SCLCs 1. Radionuclide-labeled octreotide scintigraphy is helpful in detecting tumors that may be missed by other diagnostic studies, especially since up to 80% of bronchopulmonary NETs express somatostatin receptors 1. Other treatments may include targeted therapies, chemotherapy, or peptide receptor radionuclide therapy, with the goal of improving quality of life and reducing morbidity and mortality in patients with these indolamine-producing tumors.

From the Research

Indolamines Tumor

• Indolamines are a type of biogenic amine that can be secreted by carcinoid tumors, a type of neuroendocrine tumor 2, 3, 4, 5, 6
• Carcinoid tumors can produce various substances, including serotonin, which can cause symptoms such as flushing, diarrhea, and wheezing 2, 3, 4, 5
• Somatostatin analogs, such as octreotide and lanreotide, are commonly used to treat carcinoid syndrome and can effectively control symptoms in up to 93% of patients 2, 3, 4, 5, 6
• The use of somatostatin analogs can also slow or arrest tumor growth in some cases, although tumors may continue to grow in general 4, 6

Treatment Options

• Octreotide and lanreotide are the most commonly used somatostatin analogs for the treatment of carcinoid syndrome 2, 3, 4, 5, 6
• Other treatment options, such as interferon-alpha, telotristat ethyl, and radionuclide therapy, may also be effective in controlling symptoms and slowing tumor growth 3, 6
• Liver-directed therapy can improve symptoms in patients with liver-dominant disease 3
• Chemotherapy and everolimus have not been shown to be effective in treating carcinoid syndrome 3

Diagnosis and Localization

• New diagnostic techniques, such as echocardiography, can help identify and localize carcinoid tumors with greater accuracy 5
• Carcinoid heart disease, which develops in the majority of patients with carcinoid syndrome, can be diagnosed using echocardiography 5