How does radioactive iodine treatment work in thyroid cancer?

Radioactive iodine treatment is a targeted therapy used primarily for certain types of thyroid cancer, particularly differentiated thyroid cancers like papillary and follicular thyroid carcinoma. When a patient receives radioactive iodine, the iodine is absorbed by the thyroid cells, both healthy and cancerous.

The correct understanding of how this treatment functions is that it selectively kills cancerous cells, which is why the answer that states it prevents thyroid cells from growing is not entirely accurate. Radioactive iodine is taken up more readily by thyroid cancer cells than by other types of cells; therefore, it focuses its destructive effects on those cancerous cells while largely sparing normal thyroid tissue when used in therapeutic doses.

By emitting radiation, the radioactive iodine damages the DNA of the thyroid cancer cells, ultimately leading to their death. This effect significantly contributes to the treatment's efficacy for patients with thyroid cancer, allowing for the targeted destruction of these malignancies within the thyroid gland.