Somatostatin Analogue Therapy in Functioning Neuroendocrine Gut Tumors

The purpose of the workshop was to critically evaluate the use of octreotide in the management of important sugical and gastroenterological conditions. The topics covered included: (1) management of functioning gut neuroendocrine tumors, (2) new approaches to localize these tumors, (3) the place of octreotide in the treatment of variceal bleedings, and (4) the use of octreotide in postoperative conditions. Octreotide therapy has been shown to be effective in the carcinoid syndrome, in which symptom control is achieved in 85% of patients, and reduction in 5-HIAA in 60%. Although tumor regression is rarely seen, prolongation of survival probably occurs. Control of diarrhea has been achieved in 84% of patients with VIPoma treated with octreotide. Similarly, octreotide has been found to provide effective control of the necrolytic, migratory dermatitis seen in glucagonoma. By contrast, insulinomas are more resistant to somatostatin agonist therapy. In the Zollinger-Ellison syndrome, octreotide is effective in alleviating symptoms and in reducing serum gastrin levels. However, its use in this syndrome has been superceded by omepra-zole. Radioiodine-labelled octreotide has been very effective in in vivo imaging of neuroendocrine tumors in the abdomen, and is now considered the best available technique for localizing these tumors preoperatively. Intraoperative localization with a hand-held gamma camera is being developed. There is an exciting future possibility to use the technique to deliver therapy to tumors. Octreotide therapy has been shown to be at least as effective as and without the adverse hemodynamic effects of Pitressin in control of variceal hemorrhage. It should be regarded as one of several modalities of therapy in the condition. It may be used to greater advantage when combined with sclerotherapy. Octreotide has also been used to treat a variety of postoperative complications. The anecdotal reports of its use in enterocutaneous fistulas show that fistula output is dramatically reduced and fistula closure is hastened. Octreotide is even more effective in the treatment of pancreatic fistulas. Several double-blind, prospective clinical trials have established the efficacy of octreotide in controlling the symptoms of the dumping syndrome. Octreotide therapy is also highly effective in the treatment of postobstructive diarrhea, but the results are mixed in diarrhea associated with intestinal stomas. Experimental studies in animals suggest that octreotide may be useful as adjunct therapy in bowel obstruction, but studies in humans have not been performed.