Drug therapy for neuroendocrine tumours (NETs)

Drug therapy is commonly used to treat and manage neuroendocrine tumours (NETs). Drugs are given for different reasons. You may have drug therapy to:

• control symptoms caused by too much of certain hormones being made and released by a tumour (functional tumour)
• slow down and control the growth of the cancer
• destroy neuroendocrine cancer cells
• relieve or control the symptoms of neuroendocrine cancer (palliative therapy)

Your healthcare team will consider your personal needs to plan the drugs, doses and schedules of drug therapy. You may receive a combination of different drugs or other treatments with drug therapy.

Somatostatin analogues are drugs that lower the amount of hormones made and released by NETs. They are mainly used to control symptoms of carcinoid syndrome. Even if you don’t have any symptoms (you are asymptomatic), somatostatin analogues may be used when there are increased levels of 5-HIAA to help reduce the risk of heart problems or control heart problems (carcinoid heart disease).

Somatostatin analogues are also used to slow down and control the growth of advanced or metastatic cancer when surgery can’t be done. The tumour may be functional or non-functional. Functional tumours make hormones that cause symptoms. Non-functional tumours may make hormones but don’t cause symptoms.

The most common somatostatin analogue used is octreotide (Sandostatin). It is available in a long-acting form (octreotide LAR) or a fast-acting form (octreotide IR). Another somatostatin analogue that may be used is lanreotide (Somatuline Autogel). It works like octreotide LAR. These somatostatin analogues are given as injections into the muscle or under the skin.

Octreotide LAR or lanreotide is standard treatment for the long-term control of symptoms and tumour growth. The drug is given once a month. It is usually taken for as long as it works. It may be taken for the rest of your life.

The fast-acting form of octreotide (octreotide IR) is given several times a day. It is often used for a short time when the drug is first started to check that you can cope with it. It is also used before surgery or other treatments to prevent and manage carcinoid crisis. Carcinoid crisis is a severe and life-threatening problem that causes flushing of the skin, low blood pressure, difficulty breathing and an irregular heartbeat.

Chemotherapy uses anticancer (cytotoxic) drugs to destroy cancer cells. It is usually only used to treat poorly differentiated neuroendocrine carcinomas when other treatments don’t work or can’t be used.

Chemotherapy may be a systemic therapy, which means that the drugs travel through the blood to reach and destroy cancer cells all over the body. Chemotherapy may also be a regional therapy. Regional therapy is given to a specific area of the body. Chemoembolization can be used to deliver chemotherapy directly to metastatic liver tumours.

The type of chemotherapy drug or combination of drugs used depends mainly on where the cancer started. Chemotherapy drugs used alone or in combination to treat NETs include:

• capecitabine (Xeloda)
• temozolomide (Temodal)
• streptozotocin (Zanosar)
• 5-fluorouracil (Adrucil, 5-FU)
• cisplatin
• carboplatin (Paraplatin, Paraplatin AQ)
• etoposide (Vepesid, VP-16)
• doxorubicin (Adriamycin)

Find out more about chemotherapy.

Targeted therapy uses drugs to target specific molecules (such as proteins) on cancer cells or inside them. These molecules help send signals that tell cells to grow or divide. By targeting these molecules, the drugs stop the growth and spread of cancer cells and limit harm to normal cells.

Targeted therapy may be used to treat advanced well-differentiated pancreatic NETs (pNETs) when surgery can’t be done and the cancer continues to grow and spread (progressive). The targeted therapy drugs used are sunitinib (Sutent) and everolimus (Afinitor). They are taken daily as a pill by mouth (orally).

Sunitinib is a targeted therapy drug called a tyrosine kinase inhibitor. Tyrosine kinases are proteins on the surface of cells that send signals to help cells grow and divide. Sunitinib blocks the action of different tyrosine kinases, which helps slow or stop cancer cells from growing and spreading. Sunitinib also works as an anti-angiogenesis drug, which means it prevents tumours from developing new blood vessels. It is usually given until the disease gets worse or you can’t cope with the side effects of the treatment.

Everolimus is a drug called an mTOR inhibitor. Mammalian target of rapamycin (mTOR) is a protein that controls cell growth and reproduction. It is abnormally activated in some types of cancer. Everolimus blocks the action of mTOR, which can stop the growth of the cancer.

Find out more about targeted therapy.

Supportive drugs may be used to manage or prevent problems caused by NETs. Some examples of supportive drugs that may be used include:

• proton pump inhibitors to decrease the amount of stomach acid
• loperamide (Immodium) to control diarrhea
• octreotide to prevent and manage carcinoid heart disease
• alpha blockers and beta blockers to lower blood pressure and control heart rate
• telotristat ethyl (Xermelo) to treat carcinoid syndrome diarrhea, along with a somatostatin analogue, in people whose diarrhea is not controlled by somatostatin analogues alone

Side effects can happen with any type of treatment for NETs, but everyone’s experience is different. Some people have many side effects. Other people have few or none at all.

If you develop side effects, they can happen any time during, immediately after or a few days or weeks after drug therapy. Sometimes late side effects develop months or years after drug therapy. Most side effects go away on their own or can be treated, but some side effects may last a long time or become permanent.

Side effects of drug therapy will depend mainly on the type of drug or combination of drugs, the dose, how it’s given and your overall health.

Octreotide and lanreotide may cause these side effects:

• gallbladder problems, including gallstones
• diarrhea
• fatty stool (steatorrhea)
• pain in the abdomen
• nausea and vomiting
• high or low blood sugar (glucose) levels

Side effects of chemotherapy depend on the type of drug or combination of drugs. Find out about common side effects of chemotherapy.

Some common side effects of sunitinib are:

• diarrhea
• fatigue
• nausea and vomiting
• taste changes
• indigestion
• sore mouth and throat
• high blood pressure (hypertension)
• abnormal liver function tests – may cause jaundice
• increased pancreatic enzyme levels – may cause pancreatitis

Some common side effects of everolimus are:

• sore mouth and throat
• skin problems, such as a rash
• fatigue
• high blood sugar
• anemia
• weight loss
• diarrhea

Tell your healthcare team if you have any of the side effects listed above or others you think might be from drug therapy. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

Details on specific drugs change regularly. Find out more about sources of drug information and where to get details on specific drugs.