From the Guidelines
Carcinoid syndrome should be treated with somatostatin analogs like octreotide (Sandostatin) at doses of 100-500 mcg subcutaneously 2-3 times daily, or long-acting formulations like Sandostatin LAR at 20-30 mg intramuscularly every 4 weeks, as recommended by the most recent guidelines 1.
Diagnosis and Treatment
The diagnosis of carcinoid syndrome involves measuring the main metabolite of serotonin, 5-hydroxyindoleacetic acid (5-HIAA), in 24-hour urine collections, with precautions taken for interference by certain foods and medications 1. Serum NET biomarkers, such as neuron-specific enolase and chromogranin A, should also be measured.
- The specificity of the urinary 5-HIAA test is close to 90% 1.
- An elevated serum level of chromogranin A has the highest reliability and accuracy among the biomarkers of NETs 1.
- Radionuclide-labeled octreotide scintigraphy is helpful in detecting tumors that may be missed by other diagnostic studies 1.
Symptom Management
For symptom management, antidiarrheals like loperamide (2-4 mg as needed) can help control bowel movements, while antihistamines such as diphenhydramine (25-50 mg) may reduce flushing episodes 1.
- Patients should avoid triggers that can worsen symptoms, including alcohol, spicy foods, and strenuous exercise.
- Surgery to remove the primary tumor is recommended when possible.
- The condition requires ongoing monitoring of serotonin levels through 5-HIAA urine tests and regular imaging to track tumor progression, as these tumors often grow slowly but can cause significant complications if left untreated.
Recent Guidelines
The most recent guidelines recommend the use of telotristat ethyl as a second-line treatment for refractory diarrhea due to carcinoid syndrome 1.
- Telotristat ethyl is the only EMA- and FDA-approved agent for this indication.
- When second-line treatment is given for controlling carcinoid syndrome, distinct from increased SSA dose or pasireotide, SSA therapy should be maintained until a significant improvement of carcinoid syndrome is observed 1.
From the FDA Drug Label
Octreotide acetate injection is indicated for the symptomatic treatment of patients with metastatic carcinoid tumors where it suppresses or inhibits the severe diarrhea and flushing episodes associated with the disease. The suggested daily dosage of octreotide acetate injection during the first 2 weeks of therapy ranges from 100 to 600 mcg/day in 2 to 4 divided doses (mean daily dosage is 300 mcg) In the clinical studies, the median daily maintenance dosage was approximately 450 mcg, but clinical and biochemical benefits were obtained in some patients with as little as 50 mcg, while others required doses up to 1500 mcg/day.
Carcinoid Syndrome Treatment: Octreotide acetate injection is used to treat the symptoms of carcinoid syndrome, including severe diarrhea and flushing episodes. The dosage ranges from 100 to 600 mcg/day, with a median daily maintenance dosage of approximately 450 mcg 2.
- Key Benefits:
- Suppresses or inhibits severe diarrhea and flushing episodes
- Dosage can be adjusted to achieve a therapeutic response
- Important Considerations:
- Doses above 750 mcg/day have limited experience
- Individual dosage adjustments may be necessary 2.
From the Research
Carcinoid Syndrome Treatment Options
- The somatostatin analogues lanreotide and octreotide have been shown to be effective in controlling flushing and diarrhea in patients with carcinoid syndrome 3, 4, 5, 6.
- Lanreotide and octreotide are equally efficacious in terms of symptom control and reduction in tumor cell markers for patients with carcinoid syndrome 3.
- A study found that 65-72% of patients experienced symptomatic improvement with somatostatin analogs, and 45-46% had a biochemical response 4.
- Increasing the dose or frequency of somatostatin analogs or switching to a different type can lead to a reduction in flushes and/or diarrhea in 72-84% of cases 4.
Patient Preference and Quality of Life
- The majority of patients (68%) preferred lanreotide due to its simplified mode of administration, which requires injection only every 10 days 3.
- No significant differences were found between lanreotide and octreotide in terms of quality of life 3.
- A study found that liver-directed therapy can improve symptoms in 82% of CS patients with a liver-dominant disease 4.
Other Treatment Options
- The serotonin synthesis inhibitor telotristat ethyl reduced bowel movements in 40% of patients with diarrhea refractory to somatostatin analogs 4.
- Interferon-alpha controlled CS symptoms in 45-63% of cases 4, 6.
- Radionuclide therapy has shown favorable response in subgroup analyses of studies not specifically involving CS patients 4.
- Chemotherapy and everolimus did not induce a significant response in the CS 4.