Review article: somatostatin analogs in the treatment of gastro-entero-pancreatic neuroendocrine (carcinoid) tumors.Modlin IM, Pavel M, Kidd M, Gustafsson BI. Aliment Pharmacol Ther. 2009 Oct 21. [Epub ahead of print] Abstract Background: The discovery of somatostatin (SST) and the synthesis of a variety of analogs constituted a major therapeutic advance in the treatment of gastro-entero-pancreatic neuroendocrine (carcinoid) tumors (GEP-NETs). They currently provide the most efficient treatment to achieve symptomatic relief and have recently been demonstrated to inhibit growth. Methods: We review 35 years of experience regarding the clinical application and efficacy of SST analogs. The PubMed database (1972-2009) was searched using somatostatin as search term with combinations of terms including “treatment”; “neuroendocrine”; “carcinoid”; “tumor”; “octreotide”; “lanreotide” and “pasireotide”. Results: In a review of 15 studies including 481 patients, the slow-release formulations Sandostatin LAR(R) and Somatuline SR(R)/Autogel(R)) achieved symptomatic relief in 74.2% (61.9-92.8%) and 67.5% (40.0-100%), biochemical response in 51.4% (31.5-100%) and 39.0% (17.9-58%), and tumor response in 69.8% (47.0-87.5%) and 64.4% (48.0-87.0%), respectively. Novel SST analogs, like SOM230 (pasireotide) that exhibits pan SST receptor activity and analogs with high affinity to specific somatostatin receptor (sstr) subtypes may further advance the field, but efficacy studies are lacking. Conclusions: As more precise understanding of NET cell biology evolves and molecular biological tools advance more accurate identification of individual tumors sstr profile will probably facilitate more precise delineation of SST analog treatment.