The use of somatostatin analog in gastroenteropancreatic tumors other than carcinoid.

We have used the gastrinoma syndrome to examine the effects of SMS. Acutely, SMS decreased acid secretion and restored the BAO/MAO to normal in eight of eight patients. Basal and secretin-stimulated gastrin responses were suppressed but not normalized. Treatment for up to 2 years with SMS controlled symptoms, suppressed serum gastrin, and suppressed acid secretion. Treatment for 1 year or longer decreased tumor secretion of gastrin and diminished basal acid secretion, an effect that persisted for 48 hours after withdrawal of SMS. SMS treatment arrested progression of tumor growth only in patients in whom there was a reduction in gastrin and gastric acid secretion. In patients with metastatic disease who had high levels of gastrin, SMS treatment for 5 to 24 months did not inhibit tumor growth or decrease gastrin levels. In those patients in whom a reduction in the blood flow to liver tumors was shown angiographically, there was a progressive improvement in hormone secretion and in tumor size in the ensuing year of treatment, suggesting that a major target of SMS is that vascular supply of the tumors. Tumors shown to produce peptides other than gastrin, for example ACTH, were found to be markedly resistant to the action of SMS and continued to grow in an unbridled manner.