Somatostatin analog Sandostatin and inhibition of tumor growth in patients with metastatic endocrine gastroenteropancreatic tumors

Abstract

A prospective study was performed to determine the efficacy of octreotide (Sandostatin; SMS 201-995) 200 micrograms tid in controlling tumor growth. The study included 21 patients with metastasized endocrine GEP tumors: 6 gastrinomas, 8 carcinoid syndromes, 7 nonfunctioning tumors. Treatment was performed for 3 to 59 months (median 15 months). Evaluation of the response to octreotide was facilitated in 12 patients by a pretreatment observation period of 3 to 47 months (median 17 months) during which the natural growth behavior was determined. Based on the presence or absence of a control period prior to treatment, 5 patients were considered to be responders, 7 as questionable responders (no pretreatment phase available), and 9 as nonresponders. None of the 21 patients had documented shrinkage of the tumor mass. The most favorable response was tumor standstill. In all but one responder an escape to an initially favorable response occurred after 6 to 28 months (median 14 months). Proved inhibition of growth was paralleled by a reduction of serum and urine hormone parameters, whereas unaltered progression of tumor growth was observed also in the presence of hormone suppression. Tumor growth and hormone release was inhibited in the absence and presence of somatostatin receptors on the tumor. It is concluded that octreotide exerts a limited effect on metastatic GEP tumor growth. The evaluation of a response to octreotide is facilitated by an observation period prior to the drug that provides information on growth characteristics of the tumor. The presence of octreotide receptors does not predict the success of therapy.

Treatment of Neuroendocrine GEP Tumours with Somatostatin Analogues

“…This is important since tumour growth in patients with metastatic neuroendocrine carcinoma is not uniform. Neuroendocrine malignancies can exhibit long phases of spontaneous tumour standstill or reveal exploding growth [49](fig. 2).…”

Interferon-α versus Somatostatin or the Combination of Both in Metastatic Neuroendocrine Gut and Pancreatic Tumours

“…Several studies describe tumour regression upon treat ment with low doses of somatostatin analogues in individ ual cases [6][7][8]. Since a dose-dependent anti-proliferative…”

Established Clinical Use of Octreotide and Lanreotide in Oncology

“…In a German multicenter trial, 52 patients with different forms of neuroendocrine malignancies and CT-documented tumor progression were treated with octreotide 200 Ìg t.i.d. [51]. Stabilization of tumor growth was achieved in 19 of 52 patients (36%) for a median duration of 18 months.…”