The antiproliferative effect of somatostatin analogs: clinical relevance in patients with neuroendocrine gastro-entero-pancreatic tumours.

Somatostatin analogs (SSAs) have an important role in the management of patients with neuroendocrine tumours of the gastrointestinal tract and pancreas (GEP NETs). These compounds can control the symptoms induced by the production of hormones and peptides. The antiproliferative effects of SSAs and especially tumour shrinkage are less obvious in patients with GEP NETs than in those with acromegaly. However, based upon phase II experience there is a strong suggestion of a disease stabilizing effect of SSAs in selected patients. Those patients with a progressive, non-functional GEP NET, positive octreotide scintigraphy, a low proliferation index and in the absence of surgical options may benefit from a first-line medical therapy with SSAs. The exploration of the mechanisms of this effect are unclear and hampered by the lack of suitable preclinical models. The better understanding of the tumour biology of GEP NETs, together with the development of new SSAs with better affinity on all somatostatin receptors, represent an unmet medical need.