Neuroendocrine tumours

Neuroendocrine tumours may be divided into carcinoids, originating from the lung, thymus and gastrointestinal tract, and endocrine pancreatic tumours. A substantial proportion of the tumours are malignant. Neuroendocrine tumours may secrete hormones, giving rise to endocrine syndromes such as the carcinoid syndrome, Zollinger–Ellison syndrome, hypoglycemia, the glucagonoma syndrome, Werner–Morrison's syndrome or Cushing's syndrome. Surgery to remove the primary tumour and lymph node metastases constitute an important part of the treatment. Debulking of liver metastases can be performed by surgery, radiofrequency ablation or liver embolization with particles or cytotoxic drugs. The medical treatment of metastatic midgut carcinoids consists of alpha-interferon and somatostatin analogs, which may lead to tumour stabilization and alleviation of endocrine symptoms. Alpha-interferon combined with somatostatin analogs is also an alternative in patients with endocrine pancreatic tumours, although chemotherapy with streptozotocin + 5-FU or doxorubicin is usually chosen as first-line therapy in these patients. Chemotherapy with various drug combinations is the first choice in patients with lung or thymic carcinoids and in patients with poorly differentiated neuroendocrine carcinomas. Targeted irradiation treatment with octreotide/octreotate labelled with 111In, 90Y or 177Lu may be tried in patients with metastatic tumours with high density of somatostatin receptors. Novel treatments, acting by inhibition of angiogenensis or targeting growth factor receptors, are currently being studied.