Diagnostic Approach and Management of Carcinoid Tumors

Initial Evaluation

The European Society for Medical Oncology recommends a diagnostic approach for carcinoid tumors that includes specific biochemical tests, advanced imaging studies, and histopathological confirmation using appropriate invasive techniques based on tumor location 1
Initial biochemical tests should include serum chromogranin A and 24-hour urine 5-hydroxyindoleacetic acid (5-HIAA), with renal and hepatic function tests, calcium, and glucose levels also evaluated 1
Patient preparation is critical for accurate 5-HIAA measurement, with dietary and medication restrictions that must be strictly followed, as advised by the European Neuroendocrine Tumor Society 2

Computed tomography (CT) with contrast is the gold standard for imaging, with a level of evidence 3 and grade B recommendation, and CT scans of the chest and abdomen are recommended for preoperative staging (strong recommendation) 1
Multifaceted CT with arterial and portal phases is recommended for detecting hepatic metastases, and somatostatin receptor scintigraphy (SRS) with SPECT/CT of the chest can visualize up to 80% of primary tumors, with a level of evidence 4 and grade B recommendation 1
PET with Gallium-68-DOTA is more sensitive and preferred over SRS if available, and PET with FDG is recommended for atypical or poorly differentiated carcinoids 1
The following diagnostic procedures are recommended:

Diagnostic Procedure	Recommended Use
Multiphase CT or MRI	First-line imaging for suspected carcinoid tumors
Chest CT	Assess for lung metastases or primary bronchopulmonary carcinoid
24-hour urine 5-HIAA collection	Biochemical test for suspected carcinoid syndrome
Chromogranin A measurement	General tumor marker for monitoring disease progression
Somatostatin receptor imaging	Initial evaluation for suspected carcinoid tumors

Histological examination with immunohistochemical detection of neuroendocrine markers (chromogranin A, synaptophysin, and neuron-specific enolase) is recommended, and the World Health Organization classification system is used to classify carcinoid tumors into typical, atypical, large cell neuroendocrine carcinoma, and small cell lung carcinoma based on mitotic activity and necrosis 5

Respiratory function tests are recommended to evaluate surgical risk and detect bronchostenosis, and evaluation for carcinoid syndrome is recommended, which is present in approximately 2% of patients with pulmonary and thymic carcinoids 1, 6
Echocardiography is recommended in patients with carcinoid syndrome to evaluate right and left heart valve function, and CT or MRI of the brain is recommended in cases of suspected brain metastases 1
Site-specific evaluations, such as colonoscopy and small bowel imaging for jejunal/ileal/colon carcinoids, endoscopic ultrasound for duodenal and gastric carcinoids, proctoscopic examination for rectal carcinoids, and bronchoscopy for bronchopulmonary carcinoids, are essential for determining the extent of disease, as recommended by the National Comprehensive Cancer Network 7

The National Comprehensive Cancer Network recommends surgical resection as the primary treatment approach with curative intent for most localized carcinoid tumors, with specific surgical approaches based on tumor location 7
Somatostatin analogs, such as octreotide LAR 20-30 mg IM every 4 weeks, are the first-line therapy for controlling symptoms and tumor growth in metastatic disease, with a response rate of 65-72%, as reported by the European Society for Medical Oncology 1
Liver-directed therapies, including surgical resection of liver metastases, transarterial chemoembolization, and radiofrequency ablation, are recommended for liver-dominant disease, according to the European Society for Medical Oncology 1
Peptide receptor radionuclide therapy is an option for patients with tumors showing strong somatostatin receptor expression, as recommended by the European Society for Medical Oncology 1

Regular follow-up with CT scans, chromogranin A measurements, and somatostatin receptor scintigraphy is recommended for monitoring disease recurrence and progression, as advised by the European Society for Medical Oncology 1
Prophylactic octreotide is recommended before invasive procedures to prevent carcinoid crisis, along with avoidance of drugs that release histamine or activate the sympathetic nervous system, as advised by the European Neuroendocrine Tumor Society 2
CgA levels should be measured every 3-6 months during treatment to evaluate response, and response evaluation should include both biochemical markers and imaging, as recommended by the European Society for Medical Oncology 8
Cardiac evaluation should include echocardiography at diagnosis and during follow-up to assess for carcinoid heart disease, with both right and left heart valves evaluated, as recommended by the European Society for Medical Oncology 9, 1, 7, 10
5-year survival rates vary depending on disease stage, with localized disease having a 60-100% survival rate, regional disease having a 40% survival rate, and metastatic disease having a 25-60% survival rate, and prognostic factors include WHO grade, TNM stage, functional status, presence of distant metastases, and completeness of resection, as reported by the European Society for Medical Oncology 4