Endocrine Abstracts

Neuroendocrine tumours, or NETs, are a heterogeneous group of tumours which may arise from many sites, but primarily from the gastro-entero-pancreatic (GEP) system, and the respiratory system as bronchial and occasionally thymic NETs. Many small NETs are diagnosed incidentally as appendiceal or gastric NETs, and generally act in a totally benign manner. Diagnosis is contingent on positive histopathology (positive chromogranin immunostaining, grading 1-3 based on the Ki-67 index), CT and MRI scanning, and especially functional imaging with ⁶⁸Ga-dotatate PET scanning for somatostatin receptors and ¹⁸FDG-PET scanning for proliferative activity. However, there is no clear distinction between benign NETs and those which become metastatic, and all should be assessed in specialist centre with a multidisciplinary team. In many cases, such as most gastric NETs on a background of atrophic gastritis, or small pancreatic NETs, these may simply be observed with periodic surveillance. For more advanced NETs, the only curative option is surgery; however, this may be also offered even when the tumour is metastatic, with residual disease treated with a somatostatin analogue such as monthly octreotide LAR or lanreotide autogel, both of which have been shown to retard tumour progression. For more extensive or progressive disease, peptide receptor radionuclide therapy (PRRT) is a well-tolerated and highly effective treatment. In the face of more aggressive disease, various chemotherapy regimes are available, especially capecitabine/temozolomide for well-differentiated tumours and etoposide-platinum for poorly differentiated tumours. Molecular targeted therapy can also be used, such as sunitinib for pancreatic NETs, or everolimus for GEP/bronchial NETs. Currently, the outlook for patients treated at major centres is relatively good, with prolonged survival and a good quality of life even even metastatic. Increasing studies into new targeted therapies should further improve these outcomes in the near future.