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do I need  radioactive iodine to treat my thyroid cancer?


Radioactive iodine (radioiodine) therapy is a well established treatment for thyroid cancer that has been used for over 50 years. It is a safe, effective targeted therapy which has has minimal side effects.  It comprises  a radioisotope of iodine (I 131)  administered as a single oral capsule. The radioactive iodine travels to any thyroid cell in the body and destroys it, with only minimal uptake into other organs in the body, predominantly the salivary glands.


Does everyone with thyroid cancer need to have radioactive iodine therapy? Radioiodine therapy is used for the following reasons:


  • to enable a whole body scan to be performed to detect any metastases

  • to eradicate any metastases that may have spread before surgery

  • to treat any thyroid cancer which comes back after surgery

  • to ensure all normal thyroid tissue is eradicated to facilitate long term follow-up with blood tests for thyroid cancer (serum thyroglobulin)


The decision as to whether or not radioactive iodine should be used  is best made in consultation with your endocrinologist and endocrine surgeon and depends upon the staging of the cancer.


Low risk thyroid cancer: small papillary cancers in younger patients without any evidence of spread into the lymph glands  or local tissues are considered low risk with a cure rate approaching 99%.  Radioactive iodine therapy is often not used in this situation as there is no evidence it improves the cure rate.


Intermediate risk thyroid cancer: thyroid cancers with a more aggressive histological pattern, or where the cancer has already spread into  the local lymph glands in the neck or the local soft tissue, or where the patient is older, will generally benefit from radioactive iodine therapy.


High risk thyroid cancer: thyroid cancer which has already spread elsewhere in the body distant metastases), where there is invasion of local organs, or where the cancer could not be completely removed at surgery should always be treated with radioactive iodine therapy.


More detailed information on radioactive iodine therapy can be found in the American Thyroid Association Guidelines on the Management of Thyroid Nodules 



Professor Delbridge thyroid surgeon Sydney Australia thyroid cancer radioactive iodine
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