Selective internal radiation therapy for neuroendocrine tumours that have metastasised to the liver

Neuroendocrine tumours grow in many organs of the body. The tumours start in cells that release hormones into the bloodstream (neuroendocrine cells). The tumours commonly spread (metastasise) from other organs to the liver, where it may not be possible to remove them with surgery. Some metastatic neuroendocrine tumours produce hormones that can cause carcinoid syndrome. The main symptoms of carcinoid syndrome are flushing of the skin, diarrhoea, fast heart rate and breathlessness. Some people with uncontrolled carcinoid syndrome may develop carcinoid heart disease and mesenteric fibrosis. This can reduce quality of life and prognosis, and limit what treatments can be offered.

Current treatment options depend on the history, and the clinical and histological presentation of the metastatic neuroendocrine tumours. They include:

• surgical resection

• percutaneous ablation

• systemic chemotherapy

• systemic somatostatin analogues

• peptide receptor radiation therapy

• other intra-arterial therapies such as:

  • transarterial bland embolisation

  • transarterial chemoembolisation

  • drug-eluting-bead transarterial chemoembolisation.

In selective internal radiation therapy (SIRT), microspheres containing sources of beta radiation (either the radioactive isotope Yttrium-90 or Holmium-166) are infused through the hepatic artery and carried by blood flow to the vessels that supply the tumour. Infusion through this route minimises damage to healthy liver tissues because they are mainly supplied by the portal vein, whereas the tumours are mainly supplied by hepatic arteries.

The procedure is done in 2 stages. First, the work-up is done to assess blood supply to the tumour, assess lung shunt, exclude extrahepatic uptake and plan personalised dosimetry. Then during SIRT, the microspheres containing the radionuclide are infused through a catheter placed in the hepatic artery. Catheterisation is done under local anaesthetic.