Treatment
The treatment of carcinoid syndrome requires peripheral treatments that address its various symptoms: diuretics for heart disease, bronchodilators for wheezing, as well as targeted treatments - such as somatostatin analogues — that work at the site of carcinoid tumors to inhibit hormone secretion and relieve diarrhea and flushing (1, 2, 3).
Treatment of Carcinoid Tumor and Syndrome
A two-sided approach to the treatment of carcinoid tumors focuses first on treatment of the tumor, and second on treatment of the syndrome (3). Tumor management involves surgical resection when possible and subsequent chemotherapy or interferon treatment, or hepatic embolization when hepatic metastases are prevalent. Surgical resection of local disease (and regional nodal or hepatic metastases) can result in cure or symptom relief. Radiation therapy and chemotherapy are not generally beneficial and are used primarily for symptom relief (1, 2).
According to National Comprehensive Cancer Network (NCCN) guidelines for neuroendocrine tumors, carcinoid syndrome from recurrent or unresected disease can be managed by immediate release Sandostatin® Injection (octreotide acetate) 150 mcg subcutaneous TID. If tolerated, Sandostatin LAR® Depot (octreotide acetate) 20 mg intramuscular may be considered for monthly maintenance therapy. The dose can be gradually increased as needed. In addition, "rescue" injections of immediate release Sandostatin® Injection may be used to help with breakthrough carcinoid syndrome symptoms (4).
Treatment of VIPomas
Most VIPomas are malignant, but patients can live for many years with metastatic disease if the symptoms can be controlled (3).
First-line therapy for VIPoma consists of replenishing fluids and electrolytes to correct the profound hypokalemia, dehydration, and metabolic acidosis _ up to 5 L/day of fluid and more than 350 mEq/day of potassium (3). When possible, surgery is used to eliminate the tumor responsible for VIP secretions. For patients with no metastases, surgery may result in a cure. On the other hand, for patients with metastases, surgical debulking may temporarily relieve symptoms.
Although numerous drugs such as prednisone, clonidine, and loperamide have been used to treat the diarrhea, immediate release Sandostatin® Injection and Sandostatin LAR® Depot (octreotide acetate for injectable suspension) provide short- and long-term control of diarrhea in a majority of patients. It is effective in VIPoma/watery diarrhea syndrome for a majority of patients in whom diarrhea and hypokalemia are resistant to other modes of therapy (3).
For patients with symptomatic metastatic disease, chemotherapy may be provided. Chemotherapy alone has been relatively ineffective, but may be more useful in combination with surgical resection (3).
Since the numbers of patients with VIPomas are so small, conclusive data are not available for evaluating the efficacies of the different treatment protocols. However, all of the treatment options discussed in the following section for carcinoid tumors have been used successfully in small numbers of patients (3).
References
- Creutzfeldt W, Stockmann F, Carcinoids and carcinoid syndrome. Am J Med. 1987;82(5B):4-16.
- Diaco DS, Hajarizadeh H, Mueller CR, et al, Treatment of metastatic carcinoid tumors using multimodality therapy of octreotide acetate, intra-arterial chemotherapy, and hepatic arterial chemoembolization. Am J Surg. 1995;169(5):523-8.
- Norton JA, Levin B, Jensen RT, Cancer of the endocrine system, in Cancer: Principles & Practice of Oncology. 4th ed, V.T. DeVita, S. Hellman, and S.A. Rosenberg, Editors. 1993, JB Lippincott: Philadelphia, PA. p. 1333-1435.
- National Comprehensive Cancer Network. Neuroendocrine tumors: carcinoid tumors. Management of recurrent or unresected disease, in Practice Guidelines in Oncology - v.2.2005 June 13, 2005. P. CARC 4, MS-12-MS-14.
