Antitumour activity of somatostatin analogues in progressive metastatic neuroendocrine tumours

A few studies have suggested an antitumour activity of somatostatin analogu es in neuroendocrine tumours (NET). The aim of this study was to evaluate t he antitumour efficacy of somatostatin analogues in patients with documente d progressive tumours. 35 consecutive patients with documented tumour progr ession were treated with somatostatin analogues. Patients were classified i nto two groups. In Group 1, tumours were progressing rapidly (an increase o f 50% or more in the lesion surface area in 3 months) and in Group 2, tumou rs were progressing more slowly (an increase of less than 50% in the lesion surface area in 3 months but greater than 25% in 6 months). Treatment cons isted of subcutaneous (s.c.) octreotide, 100 mug thrice daily for 17 patien ts, intramuscular lanreotide, 30 mg/every 14 days for 11 patients and for 7 patients both somatostatin analogues were used successively during the fol low-up. Primary tumour sites were the small intestine (n = 12), pancreas (n = 13). lungs (n = 5). and other sites (n = 5). 18 patients had the carcino id syndrome with flushing and/or diarrhoea. The median duration of treatmen t was 7 months. Treatment was discontinued in 3 patients due to side-effect s. One patient (3%) achieved a partial response and the disease was stabili sed in 20 patients (57%) for a median duration of 11 months (6-48 months). Stabilisation of patients in Group 1 was significantly less frequent at 6 m onths than that of patients in Group 2 (4/12 and 13/17 respectively, P <0.0 2). Somatostatin analogue treatment resulted in one partial response (3%) a nd 20 cases of stabilisation (57%) in 35 patients with progressive NET. A s low tumour growth rate before treatment is predictive of a good response to somatostatin analogues which could be considered an option for first-line treatment. (C) 2001 Elsevier Science Ltd. All rights reserved.