Gastroenteropancreatic endocrine tumors: effect of Sandostatin on tumor growth. The German Sandostatin Study Group.

One hundred fifteen gastroenteropancreatic (GEP) patients with malignant endocrine tumors entered a prospective multicenter trial (12 patients with gastrinoma, 53 with carcinoid syndrome, 45 with nonfunctioning tumors, and five with other endocrine GEP tumors) to determine the efficacy of 200 micrograms Sandostatin three times a day in the control of tumor growth. This interim report describes the results in 85 patients. Thirty-four patients died, 14 before and 20 after the first follow-up investigation, indicating a "negative" selection of patients included in the trial and suggesting that Sandostatin cannot prevent disease progress when it is far advanced. In the evaluation of 68 patients monitored for at least 3 months, partial regression was observed in 4.4%, stable disease in 50%, and tumor progression in 45%. However, an initially favorable response frequently occurred with a decrease in response later: 54.4% at 3 months to 38% at 12 months for the whole group of patients. Proven inhibition of tumor growth was mirrored by suppression of serum and urine hormone parameters. It is concluded that Sandostatin exerts a beneficial effect on tumor growth in patients with metastatic endocrine GEP tumors. This beneficial effect decreases with time and is as yet unpredictable in the individual patient.