Somatostatin Analogs and Interferon in the Treatment of Neuroendocrine Tumors

The somatostatin analogs (SSAs) octreotide and lanreotide represent an important treatment for patients with metastatic well-differentiated neuroendocrine tumors (NETs). Both drugs have been shown to substantially delay disease progression in midgut NETs (PROMID trial) and enteropancreatic NETs (CLARINET trial). Moreover, both drugs can decrease the secretion of hormones associated with malignant NETs such as serotonin glucagon and gastrin, thereby palliating symptoms such as flushing and diarrhea. Due to their benign side effect profile, either long-acting octreotide or lanreotide are typically prescribed in the first-line setting to treat metastatic, unresectable, and somatostatin-receptor positive gastroenteropancreatic NETs. The role of interferon-α (IFN-α) is more controversial. Small studies suggest that this drug can palliate the carcinoid syndrome, particularly in patients with suboptimal symptom control on somatostatin analog therapy. Small randomized studies, primarily from the 1980s and 1990s, have indicated that the drug may delay progression and even prolong survival: however, these studies were generally underpowered. Due to inconclusive data and side effects associated with the drug, interferon-α is rarely used these days.