Interferon is used both in secreting carcinoid tumours and other neuroendocrine tumors on its own or added to long acting somatostatin analogues if the patient is not responding to the maximum dosage of somatostatin analogues. Interferon-alpha 3–5 MU 3–5 times per week subcutaneously is the usual dose employed. However, there is conflicting evidence as to its efficacy, with only one major group supporting its widespread use and there is some evidence it may have greater effect in tumours with low mitotic rate. There has been biochemical response in 40–60% of patients, symptomatic improvement in 40–70% of patients, and significant tumour shrinkage in a median of 10–15% of patients. In combination with somatostatin analogues, the effect may be enhanced.
Despite questions, there multiple confirmatory studies and several guidelines now mention Intron A as a standard option.
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Kolby L, Persson G, Franzen S, et al. Randomized clinical trial of the effect of interferon alpha on survival in patients with disseminated midgut carcinoid tumours. Br J Surg 2003;90:687–93.
Faiss S, Pape UF, Bohmig M, et al. Prospective, randomized, multicenter trial on the antiproliferative effect of lanreotide, interferon alfa, and their combination for therapy of metastatic neuroendocrine gastroenteropancreatic tumors—the International Lanreotide and Interferon Alfa Study Group. J Clin Oncol 2003;21:2689–96
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