Thyroid Cancer Risk Radiation

The relationship between thyroid cancer and radiation is complex. On one hand, exposure to radiation is a proven risk factor for thyroid cancer. On the other hand, radioactive iodine treatment and thyroid radiation treatment are both widely used methods to halt the progress of the disease.

Radiation Exposure and Thyroid Cancer Rates

Experts have established that radiation exposure from fallout or nuclear accidents and some medical procedures is a contributing factor in many thyroid cancer cases. Experts point to increased thyroid cancer rates among survivors of the World War II atomic bombings in Japan and victims of the 1986 accident at the Chernobyl nuclear plant.

In the United States, National Cancer Institute researchers determined that nuclear testing in Nevada in the 1950s resulted in 7,500 to 75,000 thyroid cancer cases in individuals who were exposed to excessive radiation.

Also during the 1950s, children were sometimes treated with radiation for tonsillitis and acne. Eventually, concerns about the link between thyroid cancer and radiation put an end to the practice.

The Hanford Nuclear Site in Washington State was built in 1943 to produce plutonium for nuclear weapons. It also produced significant amounts of radioactive iodine-131, which were released into the surrounding air, water and soil between 1944 and 1957. Concerns over perceived increases in rates of thyroid cancer and thyroid disease prompted a government investigation. The study found no impact on thyroid cancer rates from the nuclear site. However, a follow-up study found errors in the study and the controversy continues.

While some may debate the extent of the relationship between thyroid cancer and radiation, the mechanism is fairly clear. Radioactive iodine dispersed into the environment makes its way into the food chain. When people consume this tainted food, their thyroid glands absorb the radioactive iodine and their risk for thyroid cancer goes up.

Radiation Exposure and Curing Thyroid Cancer

Interestingly, radioactive iodine treatment is based on the propensity of thyroid cells to pick up iodine. During treatment, radioactive iodine is taken in pill or liquid form. Once in the bloodstream, thyroid cancer cells absorb the iodine and are killed by the radiation.

Radioactive iodine treatment is very targeted and doesn’t affect other organs, because only thyroid cells absorb iodine. However, not all thyroid cancer cells absorb iodine. Radioactive iodine treatment is used only in cases of follicular and papillary thyroid cancer, and is used specifically to kill any cancer cells remaining after surgery or to treat thyroid cancer that has spread or recurred.

Radiotherapy, or thyroid radiation treatment, also uses radiation to kill thyroid cancer cells, but this time the source is external. During this process, a large machine outside the body is focused on a small area, and sends radiation to the tumor to kill cancer cells. It is usually conducted on an outpatient basis and spread out over several weeks to protect healthy tissue.


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