Surgery is only curative if the primary tumour is found before it has metastasised. This is a rare scenario and implies in particular to extraintestinal tumours such as bronchial carcinoids and ovarian carcinoids. In these situations, standard operations to remove them such as pulmonary lobectomy (removal of the affected lobe of the lung) or oophorectomy (removal of the affected ovary) can be curative. Unfortunately, such tumours make up only 11% of all carcinoid tumours, and these must be found before they have spread.
Normally surgery in carcinoid syndrome involves the palliation of symptoms by the control of liver secondary tumours, as opposed to cure. Most surgery is done under general anaesthetic (unless stated below). Anaesthesia in carcinoid syndrome is quite dangerous, with risks of narrowing of the airways, blood pressure changes, blood sugar changes, diarrhoea, flushing and vomiting. More detail can be found on this in the 'Endocrine Anaesthesia' section of this website.
This describes the surgical removal of parts of the liver or localised removal of tumour deposits. It is a major operation, curative only when the tumour is localised to a small area of the liver. Unfortunately, it is usually the case that the tumour diffusely affects many parts of the liver making surgical resection of lobes and enucleation of individual deposits more risky than the potential benefits of the operation.
Hepatic artery ligation
The principle of this is that cutting off the arterial supply to the liver by ligating (tying off) the hepatic artery and its associated collaterals (small blood vessels) reduces oxygen supply to tumour tissue by 90% (as they are very vascular tumours) whilst reducing oxygen supply to healthy tissue by only 50%. This is because the healthy liver receives blood from another source as well (the portal vein). Unfortunately death of normal liver tissue occurs in up to 25% cases and operative mortality is as high as 22%. Of those who do survive 70% show a good response, although it is short lived.
Temporary hepatic artery occlusion
This is where the hepatic artery collaterals are completely ligated. The hepatic artery itself is taken outside the wall of the abdomen on some nylon slings. These slings may be tightened temporarily after the operation to occlude the hepatic artery, and then released again. This lessens the chance of liver necrosis and complications of complete artery ligation. The success rate is approximately the same as for the next technique of embolisation.
This is where the specific small arteries feeding the liver tumours are blocked off (embolised) using a mixture containing:
The emboli are placed through a long catheter (tubes) guided to the hepatic artery from the femoral artery in the leg. This can be done under local anaesthetic, removing the complications of a general anaesthetic. Blocking off the specific blood supply to the tumours therefore damages the healthy liver tissue less.
A number of physiological markers can be used to assess whether embolisation has been successful. These are illustrated below.
Specific embolisation of arteries feeding the tumours can result in the death of tumour tissue quite quickly. This can cause the release of lots of hormones from such tumours which can precipitate the carcinoid syndrome symptoms very quickly (so-called carcinoid crisis). This is avoided by using blocking agents before, during and after the operation.
The success rate is quite good, with the median length of remission of symptoms in one group of 23 patients being 11 months. However, there is about a 1% risk of the liver being damaged so much as to cause death.
Much work needs to be done in this area to provide the best possible chance of alleviation of symptoms in carcinoid syndrome.