Octreotide is the most effective drug to ease the symptoms of carcinoid syndrome and there is some evidence to suggest that as well as easing symptoms octreotide can also sometimes cause an actual reduction in size of the tumours.

Even so, however, the benefit is usually temporary, lasting on average between 6 to 12 months (although sometimes much longer responses are seen).

There are a number of other options for treatment. These include surgery, radioactive chemicals, such as MIBG and octreotide, interferon, hepatic artery embolisation, and chemotherapy.

Carcinoid tumours are often slow growing and may benefit from a partial removal of the tumour which may sometimes help to prolong life. This is one of the few situations where surgeons will consider partial removal of liver secondaries and it is not uncommon for people to live for several years despite having cancer remaining after surgery.

If surgery is not possible and there are only a few liver secondaries, then other treatment to destroy individual liver secondaries such as laser therapy and radiofrequency ablation (the use of radiowaves to destroy cancer cells) may often be helpful. About a third of carcinoid tumours take up large amounts of particular chemicals such as MIBG or octreotide. If this is the case then it may be possible to give the chemical together with radioactivity attached. Because the cancer takes the chemical into itself in relatively large quantities it also takes in the radioactivity and therefore receives much larger doses of radioactivity than the normal tissues and the treatment causes few side effects. This treatment is only possible if the cancer takes up large quantities of these chemicals so the doctor will first do a scan using a tiny amount of radioactivity and will only give the full treatment if the scan shows that there is good uptake.

Interferon is a natural part of the body's defences against infections and cancers and has now been produced as a drug which can often be helpful in controlling carcinoid tumours. Relief of symptoms from carcinoid syndrome occur in about two thirds to three quarters of patients and actual shrinkage in the amount of tumour occurs in about one third. Interferon treatment does involve regular injections of the drug under the skin, usually three times a week. Side effects include a mild flu-like illness for the first few days of treatment but after this there are usually few problems.

Hepatic artery emoblisation involves blocking the blood supply to the tumours in the liver. These are usually responsible for the chemicals which cause the carcinoid syndrome. This is done by putting a tube into the artery that provides the blood supply to the tumour and injecting a substance that blocks the artery. This is done under a general anaesthetic and so means a short stay in hospital. Sometimes the procedure causes quite a lot of pain in the liver for a day or two and so painkillers are often necessary to ease this. Although the effects are only temporary, lasting about six months on average, embolisation can be repeated and may give a further benefit.

There is some evidence to suggest that combining embolisation and interferon therapy may give better results than either treatment alone. This is not certain because one of the problems in this condition is that carcinoid syndrome is so uncommon it is difficult to do clinical trials to fully assess the different types of treatment.

Chemotherapy may also help to control symptoms of the carcinoid syndrome and the underlying carcinoid tumour in some people. The type of chemotherapy used and its effectiveness is dependent to some extent on what the cells look like under the microscope. Those that are well differentiated (look more like normal cells) grow more slowly and also respond less well to chemotherapy. Those that are poorly differentiated (look less like normal cells) grow more rapidly and often respond much better to chemotherapy.