Interferon treatment in patients with malignant carcinoids.

Thirteen patients with ileal carcinoids complicated by liver metastases were treated with human leukocyte interferon (IFN) subcutaneously (s.c.) at doses of 3-6 x 10(6) IU/day 5 days weekly during 12 months. Objective tumour response was obtained in 2 patients, based on reduction in tumour size in one patient and on reduction in tumour markers in the other. Stable disease was noted during the 12-month treatment period in 10 patients. Progressive disease was seen in one patient. This patient exhibited tumour growth, new metastases and increases in tumour markers. Among patients with daily flushing prior to treatment, 50% were free of flush after 12 months of IFN. Adverse effects, including a mild influenza-like syndrome, joint and muscle pains, tiredness and reduction of blood cells were observed but did not necessitate long-term dose reductions. Thus, IFN therapy to midgut carcinoid patients resulted in tumour response or stable disease in 12 out of 13 patients without causing severe side effects.