Types of thyroid cancer and radioactive iodine

There are several different types of thyroid cancer. Radioactive iodine is a type of radiotherapy. Whether it can help depends on which type of thyroid cancer you have. The most common types of thyroid cancer in younger people are papillary and follicular cancer. These types both respond very well to radioactive iodine treatment. Anaplastic thyroid cancer is the most common type in elderly people and external radiotherapy works well for this type of cancer but radioactive iodine does not work very well. 

The idea behind radioactive iodine treatment is quite simple really. Thyroid cells collect iodine from the blood stream and use it to make hormones. Thyroid cancer cells also have this tendency to pick up iodine. So, when doctors found that there was a radioactive form of iodine, they decided to try giving that to the thyroid cancer cells. The cells pick up the radioactive iodine as readily as they would ordinary iodine. When they have picked it up, the radiation kills them. Because the cancer cells pick up iodine so well, this treatment works even when the cancer has spread to areas outside the thyroid. Wherever they are in the body, the cancer cells pick up the radioactive iodine. 

People with thyroid cancer often have radioactive iodine treatment after surgery. The main tumour is removed and the radioactive iodine clears the body of any cancer cells that have spread. It is because this type of treatment is so successful that more than 9 out of 10 people with follicular and papillary thyroid cancer are cured. 

There is more information about this treatment in the thyroid cancer section of CancerHelp UK. There are books and booklets about thyroid cancer, some of which are free. Look in our thyroid cancer reading section.