Treatments for Thyroid Cancer

With the rising number of thyroid cancer cases, it is good to know what the treatment options are and what you can expect for each type of treatment.

Reviewer: Mohei Abouzied, MD, FACP

Frankfort Reginal Medical Center, Frankfort KY

Chemotherapy for Thyroid Cancer

Chemotherapy is the use of drugs to kill cancer cells. Unlike radiation and surgery, which are localized treatments, chemotherapy is a systemic treatment. This means that the drugs travel throughout the whole body. This means chemotherapy can reach cancer cells that may have spread, or metastasized, to other areas.

Chemotherapy is rarely used to treat thyroid cancer. It is almost exclusively used when other treatments have failed. If chemotherapy is used, it may be combined with external radiation therapy .

Chemotherapy Drugs Used for Thyroid Cancer

Examples of chemotherapy drugs that may be used to treat thyroid cancer include:

  • Bleomycin (Blenoxane)
  • Dacarbazine (DTIC-Dome)
  • Docetaxel (Taxotere)
  • Doxorubicin (Adriamycin, Rubex)
  • Paclitaxel (Onxol, Taxol)
  • Platinum agents

 

Effectiveness

Researchers are still trying to determine what the benefit of chemotherapy is for various stages of thyroid cancer and its metastases. In general, surgery is more important, as is radioablation therapy . When thyroid cancer is unresponsive to these types of treatment, however, chemotherapy with or without external radiation therapy may be tried.

If the thyroid cancer is a highly aggressive form, chemotherapy may improve survival time. Doxorubicin is the most effective single agent in this type of cancer, and it is often combined with radiation treatment.

Adverse Reactions

In general, the elderly and those with liver and kidney diseases are more likely to have adverse side effects. Therefore, chemotherapy drugs should be used with caution in these populations.

Chemotherapy can cause many side effects, such as:

  • Damage to bone marrow
  • Infertility
  • Lung condition
  • Heart condition
  • Kidney condition
  • Condition affecting the nervous system
  • Nausea and vomiting
  • Hair loss
  • Diarrhea
  • Bleeding in the gastrointestinal tract
  • Altered taste or smell
  • Mouth sores

 

Newer Treatment Approaches

Researchers continue to develop and study different strategies to slow or stop the growth of tumors. For example, a drug called vandetanib has been approved by the Food and Drug Administration (FDA) to treat medullary thyroid carcinoma (MTC). Vandetanib is designed to block the action of certain cell receptors, like the vascular endothelial growth factor (VEGF) receptor. By blocking these receptors, the drug may be able to slow or stop cancer from spreading, as well as shrink tumors.

There are a range of drugs that also inhibit growth factor receptors. The drug cabozantinib, for instance, interferes with the process that cancer cells go through to create new blood vessels, which are needed for the cancer to grow. Other treatments that are being studied include:

  • Pazopanib
  • Axitinib
  • Sunitinib

Another example of targeted therapy includes a drug called vemurafenib. This medicine is designed to treat cancer in people who have a certain mutation in a gene called the BRAF gene. Treatment with vemurafenib has show promise in slowing cancer growth and improving mortality.

 

Radiation Therapy for Thyroid Cancer

Radiation therapy is the use of penetrating beams of high-energy waves or streams of ion particles to treat disease. Radiation therapy destroys the ability of cancer cells to grow and divide. It is used usually after surgical resection to get rid of remaining thyroid gland tissue or tumor spread elsewhere.

Two kinds of radiation therapy are available for treating thyroid cancer. One is taken delivered internally and the other is delivered externally.

Radioablation Therapy and Radioactive Iodine Therapy

Radioablation therapy or radioactive iodine therapy is used after thyroidectomy (surgical removal of the thyroid) to destroy any remaining thyroid cancer cells, cancerous lymph nodes, or spread of cancer to other areas of the body. Radioactive iodine therapy takes advantage of the fact that papillary or follicular cancers often take up iodine readily. A dose of radioactive iodine is given, thyroid cells take up the iodine, and the radioactivity kills them.

This type of therapy is only appropriate for patients with follicular or papillary thyroid cancer; medullary and anaplastic thyroid cancers don’t respond well to radioablation therapy.

EffectivenessRadiation therapy is not useful in thyroid cancers which normally do not concentrate iodide such as in anaplastic or medullary cancers. Pregnant patients should not receive radiation treatment.This is a very effective way of killing any stray thyroid cancer cells remaining after thyroidectomy, cancerous lymph nodes, or thyroid cancer that has spread elsewhere in the body. Moreover, it is very effective in treating bone pain secondary to bony metastasis.
Side Effects and Possible ComplicationsWith radioablation therapy, you may experience the following unpleasant effects:

  • If there are cancer cells elsewhere in your body, these areas may become briefly swollen and painful as the iodine collects in them.
  • Nausea and vomiting during the first day or so
  • Swelling or pain in your neck
  • Dry mouth
  • Brief loss of your sense of smell or taste

In addition, men who receive large doses of radioactivity may become infertile . Women don’t usually become infertile, but are often advised to avoid pregnancy for at least one year after radioablation therapy. There is a slight increased risk of developing a second cancer.

Post-treatment Care

  • Depending on the dose of radioactivity that you receive, you may have to be isolated in the hospital for several days to avoid exposing others to radiation.
  • Suck on hard candy or chew sugar-free gum to relieve dry mouth.
  • Drink a lot of water in the days and weeks following radioablation therapy to more quickly wash the radioactivity out of your bladder.

 

External Radiation Therapy

External radiation therapy is given to patients who have either inoperable or recurrent thyroid cancer that does not readily take up iodine, or metastasis elsewhere in the body that is not appropriate for treatment with radioactive iodine. It may also be given for palliation—to ease troublesome symptoms, such as difficulty swallowing, blocked airway, metastatic bone pain, and other symptoms.

In external radiation therapy, rays are directed at the tumor from outside the body. External beam radiation may help relieve difficult symptoms.

EffectivenessExternal radiation therapy can provide symptom relief and may be the only way to slow progression of inoperable tumors, such as anaplastic thyroid cancers.
Side Effects and Possible ComplicationsWith external radiation therapy, you may experience the following unpleasant effects:

  • Dry, red, irritated skin
  • Fatigue
  • Difficulty swallowing
  • Hoarse voice

 

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