Cessation of Somatostatin Analogues After PRRT in Mid, Hind-Gut and Pancreatic Neuroendocrine Tumours

Neuroendocrine tumours (NETs) are slow growing cancers, which commonly present as metastatic incurable disease. Some neuroendocrine tumours, termed functional NETs, overproduce hormones which result in a variety of symptoms. However, approximately 75% of NETs are considered non-functional meaning that they do not result in hormone overproduction. The main treatment for both functional and non-functional NETs is somatostatin analogues (SSA, a type of inhibitory hormone). These drugs slow tumour growth and reduce hormone production. Over time, the majority of patients will experience tumour growth despite treatment with SSA therapy. When this occurs, the addition of Peptide Receptor Radionuclide Therapy (PRRT, a type of targeted radiotherapy) in combination with ongoing SSA therapy is given. However, it is not known if continuing SSA therapy after commencement of PRRT is beneficial or not. The aim of this study is to estimate the outcomes of patients with grade 1 and 2 well differentiated mid, hind-gut or pancreatic neuroendocrine tumours who have progressed on SSA therapy and receive subsequent PRRT with or without concurrent SSA.