The authors of a new study propose a relationship between the post-surgical use of radioactive iodine (RAI) treatments for thyroid cancer, and the later development of breast cancer.
Using the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database, the researchers found that young women (30-34 years) with thyroid cancer exhibited the greatest risk of developing breast cancer.
Women who were between the ages of 40 and 44 at initial diagnosis of thyroid cancer were also at significantly elevated risk, with the greatest risk appearing 15-20 years after the thyroid cancer.
The study concluded that premenopausal adult Caucasian women who are treated for differentiated thyroid cancer are at increased risk to develop breast cancer five to 20 years later.
This finding suggests that the increased risk of breast cancer after thyroid cancer is related to the thyroid cancer treatment. In particular, the RAI treatment is suspected to be the agent involved in increasing the cancer risk.
The authors' recommendation is for regular follow-up of all women patients with thyroid cancer and "judicious use of radioactive iodine as a treatment regimen."
Click here to read the American Academy of Otolaryngology -- Head and Neck Surgery Foundation release regarding this research. According to Mary Shomon, the Thyroid Guide at About.com, "of critical importance to women who have had RAI treatment for Graves' Disease is the need for a definitive study looking at whether the lower levels of RAI used to ablate the thyroid also pose an increased risk of breast cancer. Given that RAI is the preferred treatment for hyperthyroidism in the U.S., this is an important question."
Annual meeting of the American Academy of Otolaryngology -- Head and Neck Surgery Foundation Washington, D.C, October 2000.
It is very rare where one would need to destroy the thyroid with radiation to resolve a hyperactive thyroid. Nearly all autoimmune disease is related to a viral infection, a heavy metal intoxication or a parasite. If one can identify and address these underlying causes, the immune system corrects itself and the hyperactive thyroid resolves.
This is not the first time that the use of radioactive iodine has been shown to increase cancer risks (see below).
Related Article:
Radioactive Iodine For Hyperthyroidism Increases Thyroid and Small Bowel Cancer Risk