Carcinoid syndrome medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Parminder Dhingra, M.D. [2] Anum Gull M.B.B.S.[3]
Overview
The predominant therapy for carcinoid syndrome is surgical resection. Supportive therapy for carcinoid syndrome includes somatostatin analogs,Telotristat,interferons, and radionuclides.
Medical Therapy
Standard treatments for patients with gastrointestinal carcinoid tumors include the following:[1]
- Somatostatin analogue
- Telotristat
- Interferons
- Treatment of hepatic metastases
- Radionuclides
- Management of carcinoid-related fibrosis
- Surgery
Somatostatin Analogs
- Somatostatin analogs includes octreotide and lanreotide.
- Somatostatin acts by binding to somatostatin receptors expressed on the majority of carcinoid tumors.
- Flushing and diarrhea are significantly improved in over 80 percent of patients with the carcinoid syndrome with somatostatin therapy.[2]
- Experimentally, somatostatin has been shown to have a cytostatic effect on tumor cells. This effect involves hyperphosphorylation of the retinoblastoma gene product and G1 cell cycle arrest.[3]
- Lanreotide, a long-acting somatostatin analog administered every 10 to 14 days, has an efficacy similar to that of octreotide and an agreeable formulation for patient use. The effects of lanreotide on symptom relief are comparable to those of octreotide, with 75% to 80% of patients reporting decreased diarrhea and flushing. However, there appears to be little improvement in tumor responses over shorter-acting octreotide.
- Depot formulations include long-acting repeatable (LAR) octreotide and a slow-release depot preparation of lanreotide.
- The typical duration of treatment with somatostatin analogs is approximately 12 months because of the development of tachyphylaxis.
Adverse effects of somatostatin analog administration include:
- Nausea
- Cramping
- Loose stools
- Steatorrhea
- Cardiac conduction abnormalities and arrhythmias
- Endocrine disturbances (e.g., hypothyroidism, hypoglycemia, or hyperglycemia
- Gastric atony
Telotristat
- Telotristat is an oral inhibitor of tryptophan hydroxylase which catalyzes the conversion of l-tryptophan into serotonin..[4]
- Tryptophan hydroxylase is an aromatic amino acid hydroxylase and is the rate-limiting enzyme in serotonin synthesis.
- Somatostatin analogs (SSAs) are the mainstay of treatment, but are unable to ameliorate symptoms in all patients due to dose-limiting side effects and tachyphylaxis.
- Telotristat represents a significant advance in the treatment of carcinoid syndrome diarrhea in patients who have inadequate control on long-acting somatostatin analogues and should be considered for patients with >4 bowel motions per day on somatostatin analogues.
Interferons
- The most researched interferon in the treatment of carcinoid disease is interferon-alpha.
- Interferon-alpha (IFNα) is a cytokine that mediates anti-viral, anti-proliferative and anti-tumour activities.
- Side-effects includes
Treatment of Hepatic Metastases
The management of hepatic metastases may include:
- Surgical resection
- Hepatic artery embolization especially when complemented by the addition of regional chemotherapy (trans-arterial chemoembolization or TACE)[5]
- Cryoablation and Radiofrequency ablation (RFA)
- liver transplantation[6]
Radionuclides
- The use of somatostatin analogue radiolabeled peptide therapy (PRRT) provides radiation directed to the cells that express somatostatin receptors.[7]
- The four radionuclide conjugates most commonly used in the treatment of carcinoid disease are:
- It is mandatory to quantify cells with somatostatin receptors using imaging prior to PRRT therapy.
Management of Carcinoid-Related Fibrosis
- Currently, there is no effective pharmacologic therapy for bowel obstruction and heart failure secondary to peritoneal fibrosis and right-sided valvular fibrosis respectively.
- In the instance of bowel obstruction, surgical lysis of the adhesions often is technically demanding because of the cocoon-like effects of extensive fibrosis stimulated by the various tumor-derived growth factors.
- Valvular replacement usually is required to manage carcinoid heart disease.[8]
Symptomatic Therapy
- Nonspecific supportive care of patients is to avoid factors that induce flushing or bronchospastic episodes includes the following:
- Diarrhea may be treated with conventional anti-diarrheal agents such as loperamide or diphenoxylate
- Severe diarrhea may be treated with the 5-HT receptor subtype 2 antagonist cyproheptadine, which is effective in as many as 50% of patients and may also help alleviate anorexia or cachexia in patients with a malignant carcinoid syndrome.
- Treatment of skin rashes, particularly in histamine-secreting gastric carcinoid tumors can be done with histamine 1 receptor blockade with fexofenadine and loratadine
- Bronchospasm can be managed with theophylline or beta-2 adrenergic receptor agonists such as albuterol.
References
- ↑ Treatment Option Overview for GI Carcinoid Tumors . NATIONAL CANCER INSTITUTE . http://www.cancer.gov/types/gi-carcinoid-tumors/hp/gi-carcinoid-treatment-pdq#link/_97_toc Accessed on September 22, 2015
- ↑ Vinik AI, Wolin EM, Liyanage N, Gomez-Panzani E, Fisher GA (September 2016). "EVALUATION OF LANREOTIDE DEPOT/AUTOGEL EFFICACY AND SAFETY AS A CARCINOID SYNDROME TREATMENT (ELECT): A RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED TRIAL". Endocr Pract. 22 (9): 1068–80. doi:10.4158/EP151172.OR. PMID 27214300.
- ↑ Ducreux M, Ruszniewski P, Chayvialle JA, Blumberg J, Cloarec D, Michel H, Raymond JM, Dupas JL, Gouerou H, Jian R, Genestin E, Hammel P, Rougier P (November 2000). "The antitumoral effect of the long-acting somatostatin analog lanreotide in neuroendocrine tumors". Am. J. Gastroenterol. 95 (11): 3276–81. doi:10.1111/j.1572-0241.2000.03210.x. PMID 11095353.
- ↑ Chan DL, Singh S (2018). "Developments in the treatment of carcinoid syndrome - impact of telotristat". Ther Clin Risk Manag. 14: 323–329. doi:10.2147/TCRM.S126143. PMC 5824756. PMID 29503551.
- ↑ Strosberg JR, Choi J, Cantor AB, Kvols LK (January 2006). "Selective hepatic artery embolization for treatment of patients with metastatic carcinoid and pancreatic endocrine tumors". Cancer Control. 13 (1): 72–8. doi:10.1177/107327480601300110. PMID 16508629.
- ↑ Blonski, Wojciech C (2005). "Liver transplantation for metastatic neuroendocrine tumor: A case report and review of the literature". World Journal of Gastroenterology. 11 (48): 7676. doi:10.3748/wjg.v11.i48.7676. ISSN 1007-9327.
- ↑ Hörsch D, Ezziddin S, Haug A, Gratz KF, Dunkelmann S, Miederer M, Schreckenberger M, Krause BJ, Bengel FM, Bartenstein P, Biersack HJ, Pöpperl G, Baum RP (May 2016). "Effectiveness and side-effects of peptide receptor radionuclide therapy for neuroendocrine neoplasms in Germany: A multi-institutional registry study with prospective follow-up". Eur. J. Cancer. 58: 41–51. doi:10.1016/j.ejca.2016.01.009. PMID 26943056.
- ↑ Modlin IM, Shapiro MD, Kidd M (December 2004). "Carcinoid tumors and fibrosis: an association with no explanation". Am. J. Gastroenterol. 99 (12): 2466–78. doi:10.1111/j.1572-0241.2004.40507.x. PMID 15571597.