Should interferon-α and somatostatin analogs be combined in gastroenteropancreatic neuroendocrine tumor therapy?

Gastroenteropancreatic are the most common of the neuroendocrine tumors. They are usually well differentiated and slow growing, and express subtype 2 and 5 somatostatin receptors in most cases. Both somatostatin anologs and interferon-α were used as single agent, showing symptomatic, biochemical, and in a minority of cases, even antiproliferative activity. In vitro and in vivo evidence exists supporting the combined use of these drugs, but the only two randomized trials published to date did not show a statistically significant advantage for the combination compared with single-agent use. However, several reports exist from nonrandomized trials that would justify the sequential use of the two drugs or the combination after progression on single-agent therapy. Therefore, larger, international, prospective, randomized and multicentric clinical trials studying homogeneous populations are necessary in order to give a final answer.