Chemotherapy for Thyroid Cancer

Chemotherapy (chemo) uses anti-cancer drugs that are injected into a vein or are taken by mouth. Chemotherapy is systemic therapy, which means that the drug enters the bloodstream and travels throughout the body to reach and destroy cancer cells.

Chemotherapy is seldom helpful for most types of thyroid cancer, but fortunately it is not needed in most cases. It is often combined with external beam radiation therapy for anaplastic thyroid cancer and is sometimes used for other advanced cancers that no longer respond to other treatments.

The chemotherapy drugs most commonly used to treat mainly medullary thyroid cancer and anaplastic thyroid cancer include:

• Dacarbazine
• Vincristine
• Cyclophosphamide
• Doxorubicin
• Streptozocin
• Fluorouracil
• Paclitaxel
• Docetaxel
• Carboplatin

Possible side effects

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

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

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

These side effects are usually short-term and go away after treatment is finished. There are often ways to lessen these side effects. For example, drugs can be given to help prevent or reduce nausea and vomiting.

Some chemotherapy drugs may have other specific side effects that require monitoring. For example, doxorubicin (one of the most common chemo drugs used in thyroid cancer) can affect heart function. If you are taking doxorubicin, your doctor will check your heart regularly using tests such as echocardiograms.