Chemotherapy and Other Drugs for Gastrointestinal Carcinoid Tumors

Chemotherapy (chemo) uses anti-cancer drugs that are injected into a vein or a muscle or taken by mouth to kill cancer cells. These drugs enter the blood and reach almost all areas of the body, making this treatment useful for some types of cancers that have spread.

Unfortunately, gastrointestinal (GI) carcinoid tumors often do not respond well to chemo. Because of this, chemo generally is used only for tumors that have spread to other organs, are causing severe symptoms, have not responded to other medicines or are high grade (grade 3).

Some of the chemo drugs used to treat GI carcinoid tumors include:

• Capecitabine (Xeloda)
• 5-fluorouracil (5-FU)
• Doxorubicin (Adriamycin)
• Etoposide (VP-16)
• Dacarbazine (DTIC)
• Streptozocin
• Temozolomide
• Oxaliplatin

Some tumors, especially high-grade tumors, may be treated with more than one drug. For these, combinations of 5-FU plus streptozocin, 5-FU plus doxorubicin or oxaliplatin plus capecitabine may be used.

Doctors give chemo in cycles, with each period of treatment followed by a rest period to allow the body time to recover. Chemo cycles generally last about 3 to 4 weeks, and initial treatment is typically 4 to 6 cycles.

Possible side effects of chemotherapy

Chemo drugs damage cells that are dividing quickly, which is why they can work against cancer cells. But other cells in the body, such as those in the bone marrow (where new blood cells are made), the lining of the mouth and intestines, and the hair follicles, also divide quickly. These cells are also likely to be affected by chemo, which can lead to side effects.

The side effects of chemo depend on the type and dose of drugs given and the length of time they are taken. Common side effects can include:

• Nausea and vomiting
• Loss of appetite
• Hair loss
• Mouth sores
• Diarrhea or constipation
• Increased chance of infections  (from having too few white blood cells)
• Easy bruising or bleeding (from having too few blood platelets
• Fatigue (from having too few red blood cells)

Most side effects go away a short time after treatment is finished. Often medicines can help prevent or minimize many of the side effects. For example, your doctor can prescribe drugs to help prevent or reduce nausea and vomiting.

You should tell your medical team about any side effects or changes you notice while getting chemotherapy, so that they can be treated promptly. In some cases, the doses of the chemo drugs may need to be reduced or treatment may need to be delayed or stopped to keep the effects from worsening.

For more information on chemo, see Chemotherapy. 

Other drugs used for treating gastrointestinal carcinoid tumors

For people with metastatic GI carcinoid tumors, several medicines can help control symptoms and tumor growth.

Somatostatin analogs

These drugs are related to somatostatin, a natural hormone that seems to help slow the growth of neuroendocrine cells. They are especially useful in people who have carcinoid syndrome (facial flushing, diarrhea, wheezing, rapid heart rate) and in people whose tumors show up on a somatostatin receptor scintigraphy (SRS) scan or gallium-68 Dotatate scans. 

Octreotide: This drug is helpful in treating the symptoms of carcinoid syndrome. Sometimes octreotide can temporarily shrink carcinoid tumors, but it does not cure them.

The original version of octreotide (Sandostatin^®) is injected under the skin (subcutaneously) at least twice daily. Some people learn to give this injection themselves at home. A long-acting version of the drug (Sandostatin LAR^®) is injected into a muscle once a month by your doctor or nurse. Depending on the severity of symptoms, some people are given injections every day when first starting treatment. Once the doctor finds the correct dose, the longer-acting monthly injection may then be used.

Side effects can include pain or burning at the injection site, stomach cramps, nausea, vomiting, headaches, dizziness, and fatigue.

Lanreotide(Somatuline^®): This drug is similar to octreotide. It is injected under the skin once a month. It may be given by your doctor or nurse, or you may learn how to give the injection at home. Side effects are similar to those of octreotide, although pain at the injection site is less common. 

Telotristat (Xermelo™): This drug is used along with a somatostatin analog (octreotide or lanreotide) to help control carcinoid syndrome diarrhea. It is given by mouth as a pill and common side effects can include fever, poor appetite, headache, nausea, and swelling of the hands or feet

Targeted drugs

Anti-cancer drugs that work differently from standard chemotherapy drugs have been developed for some types of cancer. These drugs target specific parts of cancer cells. They are sometimes helpful when chemotherapy is not. They often have different side effects.

The targeted drug, everolimus (Afinitor^®), has been shown to help treat advanced GI carcinoid tumors. It can be used with or without somatostatin drugs, such as octreotide. Common side effects include diarrhea, fatigue, rash, mouth sores and swelling of the legs or arms.

Interferons

Interferons are natural substances that normally activate the body's immune system. They also slow the growth of some tumor cells. Interferon-alfa is sometimes helpful in shrinking or slowing the growth of metastatic GI carcinoid tumors and improving symptoms of carcinoid syndrome. Often, the drug's usefulness is limited by its flu-like side effects, which may be severe. The drug is given by injection.