Diagnosis and management of neuroendocrine tumours

Abstract

Neuroendocrine tumours (NETs) represent a heterogenous group of tumours, with diversity in their primary tumour sites, functional status (ie hormone secreting or non-functional) and degrees of aggressiveness (ranging from well-differentiated, grade 1 neuroendocrine tumours to poorly differentiated grade 3, neuroendocrine carcinomas). The most common sites are the lung, small bowel, pancreas and appendix. Clinical presentation is variable, ranging from incidental lesions detected on cross-sectional imaging, small bowel obstruction, carcinoid syndrome or other syndromic presentations (eg hypoglycaemia resulting from insulinoma) through to florid carcinoid heart disease. Diagnosis relies on biochemical markers, computed tomography (CT), magnetic resonance imaging (MRI) and somatostatin-receptor based functional imaging. Treatment comprises surgery where curative resection is possible through to approaches where disease stabilisation is the key, involving somatostatin analogues, peptide receptor radionuclide therapy (PRRT), everolimus, sunitinib, liver-directed therapies and sometimes chemotherapy. Although local and systemic complications can occur, they are associated with reasonable 5- and 10-year survival rates, respectively.

Keywords: Neuroendocrine tumour; carcinoid syndrome; neuroendocrine carcinoma; peptide receptor radionuclide therapy; somatostatin analogues.

Fig 1

Cross-sectional (computed tomography (CT) scan, axial section, arterial phase) (a) and functional imaging (Ga⁶⁸ positron emission tomography (PET)/CT scan, axial section) scan (b) showing multiple liver metastases in a patient with a metastatic neuroendocrine tumour.

Fig 2

Molecular markers: Ki-67 staining of neuroendocrine neoplasms (neuroendocrine tumours (NETs)/neuroendocrine carcinomas (NECs)) from different sites: (a) grade 1 NET (ileum), (b) grade 2 NET (lung, atypical carcinoid), (c) grade 3 NET (pancreas) and (d) NEC (small cell lung cancer).

Fig 3

Large mesenteric mass associated with a small bowel neuroendocrine tumour (NET) (a) and a multifocal small bowel NET that was surgically resected (b).