Interferon-alpha (IFN-alpha) has a direct anti-tumour effect and is
an immunomodulator. Somatostatin analogues, by contrast, when
used to treat neuroendocrine tumours, control the secretion
and peripheral effects of hormones, although at high doses
they induce apoptosis. We have used IFN-alpha to treat > 350
patients with neuroendocrine tumours, and combining our and
published data gives a median 44% biochemical response rate
and 11% tumour response rate. Side-effects are mainly
flu-like symptoms, then low-grade chronic fatigue syndrome.
15% may develop autoimmune reactions. The side-effects
profile of somatostatin analogues is better but patients must
take frequent injections and may have bile problems. We
combined IFN-alpha and octreotide treatment in 24 patients
with malignant carcinoid tumours who did not respond
biochemically to high-dose (300 micrograms/day) octreotide
alone. Biochemical response occurred in 77% but no
significant anti-tumour effect was noted besides disease
stabilisation in 4 cases. The combination therapy had an
effect on clinical symptoms rather than tumour mass.
Interferon was better tolerated when in the combination.