The treatment of a NET cancer depends on the size and location of the tumour, whether the cancer has spread, and your overall health.
These are a complex group of cancers to manage, and ideally, a MDT will work with you to determine the best treatment plan. The MDT will always have several goals in mind as they formulate your treatment plan.
Not all of the treatments described here are suitable for all people with NETs. Treatment plans should always be tailored to the individual.
The main treatment goals are listed below:
- Remove the tumour by surgery; however, if the tumour has spread, this may not be possible
- Alleviate symptoms
- Control the tumour growth
- Maintain a good quality of life for you
Some of the treatments that are used to reduce or stabilise tumour size and alleviate symptoms are discussed below.
If the tumour is contained in one area (localised), or if there has been only limited spread, surgery is usually the first choice of treatment. If it is possible to remove the tumour completely no other treatment may be necessary.
If the tumour has spread (metastasised), surgery may still be possible to remove the part of the tumour that is producing too many hormones. This is often referred to as tumour debulking.
If a GEP or NET is blocking an organ, such as the bowel, surgery may be helpful to relieve the blockage (obstruction). If the tumour has spread to the liver, surgery can be used to remove the parts of the liver containing the tumour. Very occasionally, a liver transplant may be considered.
Surgery may be used throughout a patient’s treatment plan for many reasons, including in combination with other therapies.
Somatostatin is a substance produced naturally in many parts of the body. It can stop the over-production of hormones that cause symptoms such as diarrhoea, flushing and wheezing. Lanreotide and octreotide are somatostatin analogues i.e. drugs that copy or mimic the action of somatostatin.
Some NETs produce hormones that can cause other symptoms, for example, patients with a carcinoid tumour may have diarrhoea, flushing, and wheezing. You may have different symptoms depending on the type of tumour that you have. These symptoms can be distressing and often affect your quality of life.
The aim of this treatment is to block the release of the extra hormones your body is producing and therefore improve your symptoms.
Lanreotide can be given as an injection every 7-14 days or as a long-acting injection every 28 days. The long-acting injection can be administered by a nurse, either in hospital or by a practice nurse. For some patients who are stabilised on their treatment with lanreotide, it may be possible for the patient, or a relative or friend, to be taught how to give the injection themselves. The injection is given in the upper, outer quadrant of the buttock or, if you are self-injecting, into the upper, outer thigh. If you are using lanreotide at home it should be kept in the refrigerator, in its original package, at a temperature between 2C and 8C; it should not be frozen.
Octreotide can be given as a short-acting injection two to three times a day, or as a long-acting injection administered by a healthcare professional every 28 days. The short-acting form is injected into the tissue under the skin, either in the upper arm, thigh or stomach. The long-acting form is injected in the large muscle in the buttock. Octreotide should be stored between 2C and 8C; it should not be frozen.
There may be some side effects, but it is important to remember that the following are only possible side effects and do not affect all patients:
- Loss of appetite and problems in the gastrointestinal tract (gut) such as nausea, vomiting, abdominal pain and bloating, wind, and upset bowels
- Occasional discomfort at the site of the injection
- After a period of time some patients may develop gallstones as a result of the treatment but your centre monitors this when you have your regular scans
- Short and longer-acting injections can affect blood sugar levels
Interferon is a naturally occurring substance that is produced by the body’s immune system during an illness such as a viral infection e.g. flu. It is sometimes referred to as biological therapy or immunotherapy and is used to treat some patients with NETs. Sometimes interferon is given on its own, but quite often it is given as a combination therapy with somatostatin analogues. It may not be a suitable therapy for all NET patients.
Some people may be given chemotherapy e.g. to treat pancreatic and bronchial NETs, and also for some NET tumours which are growing a little quicker than they might normally do.
The histology of your tumour will help determine whether chemotherapy will be appropriate for you or not. If you have chemotherapy the oncology team, who are specialists in this field, will look after you.
Researchers are constantly looking at various chemotherapy regimens for NET patients and this may be discussed with you at your hospital appointment.
Chemotherapy drugs are normally administered through a cannula inserted in your arm but there are also tablet forms. You can normally receive your treatment as an outpatient, although if it is your first time, you may be asked to stay in overnight just to check that you tolerate the treatment.
The drugs used, and any possible side effects, will be discussed in-depth prior to commencing any treatments and written information will also be given. You will be given many opportunities to ask questions.
You may be given an information and record book from the chemotherapy team. It might be helpful to note down the specific contact numbers for them.
If the tumour has spread to the liver, you may be offered hepatic artery embolisation (HAE). In this procedure, a catheter is placed in the groin, and then threaded up to the hepatic artery that supplies blood to the tumors in the liver. Tiny particles called embospheres (or microspheres) are injected through the catheter into the artery. These particles swell and block the blood supply to the tumour, which can cause the tumour to shrink or even die.
This treatment can also be combined with systemic treatments for people with liver metastases and metastases outside of the liver. It is a procedure that would be done by a specialist called an interventional radiologist. You will be sedated for the treatment.
Sometimes this embolisation process is combined with chemotherapy and called Hepatic Artery Chemoembolisation (HACE), or Transcatheter Arterial Chemoembolisation (TACE), or radiotherapy (Radioactive Microsphere Therapy [RMT] or Selective Internal Radiation Therapy [SIRT]).
Radiofrequency Ablation (RFA) is used if there are relatively few secondary tumours. A needle is inserted into the centre of the tumour and a current is applied to generate heat, which kills the tumour cells.
Radionuclide therapy is also called peptide receptor radionuclide therapy (PRRT) or hormone-delivered radiotherapy. It is sometimes referred to as the ‘magic bullet’. This treatment involves a similar strategy as that applied in an octreotide scan, but the dose of radiation is high enough to prevent further tumour growth or even kill the tumour.
This treatment is not available in Ireland but is offered by some very specialist centres around Europe. One such centre is the university hospital in Uppsalla, Sweden which has close links with several Irish hospitals. This treatment is accessible to Irish NET patients through the EU’s E112 system as part of their overall healthcare strategy.
Radioactive substances are chemically combined with hormones that are known to accumulate in a NET. This combination is injected, the hormones enter the tumour and the attached radiation will kill the tumour cells.
There are a number of different radioactive agents available:
- 90-Yttrium DOTATOC
You will be admitted to hospital for these treatments, but usually you will only need to stay in overnight. You will remain in a lead-lined room for 12-24 hours afterwards and have a scan the following day so the doctor can see if the active agent has been taken up correctly.
The therapy is commonly delivered intravenously through a cannula in the arm. In certain centres it can also be delivered transarterially if the doctor wants to particularly target tumours in the liver. This involves administering the treatment under sedation via an artery (see embolisation).