Radiation Therapy Treatment For Thyroid Cancer

Thyroid cancer is the cancer in the thyroid gland, an endocrine organ which produces hormones that control the speed of metabolism. Read more about thyroid cancer here.
This treatment uses high energy X rays to kill the thyroid cancers. Under strict monitored doses, dosage is given to the patients in order to control the growth of the cancerous cells. It is mainly used in treating metastasized testicular cancers. It is often given before/after surgeries or combined with chemotherapy. It is one of the most successful treatments for thyroid cancer. Read more about thyroid cancer treatment here.

Visual representation of cancer affecting the body in a microscopic level

How radiation therapy works for thyroid cancer?

Utmost accuracy and precision are needed to treat thyroid cancer using radiation therapy as it uses targeted energy like X-rays, radioactive substances to kill cancer cells, shrink tumors, and crub some symptoms related to cancer. The uses of radiation therapy for thyroid cancer are:

  • As a primary treatment to kill cancer cells when diagnosed.
  • Along with other treatments methods to stop the further division of cancer cells.
  • After a treatment method to stop the growth remnant cancer cells if any may be present.
  • To neutralize symptoms of advanced cancer.

Radiation treatment for thyroid cancer depends on what type of thyroid cancer one has and the extent to which it has spread. With advancement in radiation therapy delivery systems, targeting all kinds of thyroid tumors,with precise direction of higher radiation doses, while minimizing it’s exposure to healthy tissue is possible.

Types of radiation therapy for thyroid cancer:

External beam radiation therapy(EBRT):

External beam radiation therapy (EBRT) directs a beam of radiation from outside the body at cancerous tissues inside the body, using a special X-ray machine called a linear accelerator. It is a cancer treatment option that uses doses of radiation to destroy cancerous cells and shrink tumors. It is an anticancer treatment which uses doses of radiation to restrict the growth of cancer cells and eventually kill them. It is also used to shrink cancer tumours. Advantages of EBRT for thyroid cancer include:

  • EBRT does not carry the standard risks or complications associated with major surgery for thyroid cancer. The procedure is painless. Read more about surgery for thyroid cancer here.
  • EBRT possesses no risk of radioactivity to the patients or others with whom you have contact allowing them to carry out daily activities.

3D conformal radiation therapy, IMRT, IGRT, Tomotherapy and stereotactic radiosurgery are examples of External beam radiation therapy.

Intensity modulated radiation therapy (IMRT):

IMRT may be a promising option if one is experiencing recurrent tumors in the previously radiation therapy treated area. A computer-controlled device called a linear accelerator delivers radiation in sculpted doses that match the 3D geometrical shape of the tumor, including concave and complex shapes, allows usage of higher radiation doses than traditional therapies would allow, while sparing non cancerous tissue from harmful doses of radiation.

Radioactive iodine:

Radioactive iodine treatment is used very frequently for thyroid cancers that spread up to the lymph nodes and any other parts of the body. Its potential benefit is removal of small tumors that cannot be completely removed by surgery.
The radioactive iodine for thyroid cancer is taken in liquid form or capsule form, all iodine in bloodstream is usually used up by the thyroid gland, radioactive iodine (I-131) is used to kill thyroid gland and thyroid cancer cells in lymph nodes or any other parts of the body.

Tomotherapy for thyroid cancer:

Tomotherapy combines a form of intensity modulated radiation therapy (IMRT), with the accuracy of computed tomography (CT) scanning technology, in one machine.
Following are potential advantage for thyroid cancer patients using tomotherapy:

  • Built in CT scanning confirms exact shape and location of a tumor before treatment.
  • Deliver of precise radiation to match complex tumor shapes while avoiding sensitive structures is possible ,due to the formation of radiation beams from 360 degrees.

Side effects of radiation therapy in thyroid cancer:

Short-term side effects of radiation therapy for thyroid cancer treatment may include:

  • Neck tenderness and swelling
  • Nausea and vomiting
  • Swelling and tenderness of the salivary gland
  • Dry mouth
  • Taste changes
  • Redness of the skin
  • Odynophagia (painful swallowing)
  • Cough
  • Occasional hoarseness
  • Fatigue
  • Skin changes similar to a sunburn,which may fade away
  • Xerostomia: Because of high concentration of iodine in salivary gland tissue, swelling of the salivary glands may happen which may result in xerostomia.
  • Effect on the eyes: Radioiodine treatment may also reduce tear formation, leading to dry eyes in some people.
  • Infertility: Infertility may be seen in men who have received large doses of radiation therapy which is rare but a low sperm count is seen frequently. Woman’s ovaries may be affected leading to irregularities in menstrual cycles avoiding pregnancy for 6 months to a year after treatment is advisable.
  • Effect on the heart: Increased blood pressure and abnormalities in the heart rhythm, which increases the risk of cardiovascular diseases is a common side effect for high dosage of radiotherapy.

Most side effects vanish soon after treatment is finished. Read more about concerns after treatment for thyroid cancer here.

Dosage and survival rate:

External beam radiation therapy is given 5 days a week for several weeks. Before the treatment starts, measurements to find the appropriate angles to aim the radiation beams and the proper dose of radiation are taken .The duration of the treatment is only a few minutes.
RAI is usually given between 3 and 6 weeks after the surgery, in the form of either one or more capsules or a liquid.The dosage of I-131 used for removal is measured in millicuries. The dose for remnant ablation ranges from 30 millicuries to 100 millicuries. Sometimes a higher dose of 100 to 200 millicuries may be given for people with more extensive disease.
Radiotherapy is one of the most successful treatments for treating the thyroid cancers which cannot be reached through surgeries, as radiation can be given from different angles.

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