Thyroid Cancer

There are about 37,000 new cases of thyroid cancer each year in the US, according to the National Cancer Institute. Females are more likely to have thyroid cancer at a ratio of three to one. Thyroid cancer can occur in any age group, although it is most common after age 30, and its aggressiveness increases significantly in older patients. The majority of patients present with a nodule on their thyroid that typically does not cause symptoms. Remember, over 99% of thyroid nodules are not cancer. But when thyroid cancer does begin to grow within the thyroid gland, it almost always does so within a discrete nodule within the thyroid.

Visit our Patients' Guide to Thyroid Cancer for complete information on thyroid cancer types, causes, diagnosis, and treatments.

Symptoms of thyroid cancer
Occasionally, symptoms such as hoarseness, neck pain, and enlarged lymph nodes do occur in people with thyroid cancer. Although as much as 75% of the population will have thyroid nodules, the vast majority are benign. Young people usually don't have thyroid nodules, but as people age, they likely develop a nodule. By the time we are 80, 90% of us will have at least one nodule.

Far less than 1% of all thyroid nodules are malignant. A nodule that is cold on scan (shown in photo outlined in red and yellow) is more likely to be malignant. Nevertheless, the majority of these are benign as well. You can read more information about thyroid nodules and their potential to be malignant below:

Types of Thyroid Cancer

There are four types of thyroid cancer, and some are more common than others.

Thyroid Cancer Type and Incidence

• Papillary and/or mixed papillary/follicular ~ 78%
  
• Follicular and/or Hurthle cell ~ 17% [
• Medullary ~ 4%
• Anaplastic ~ 1%

Note: Chief Justice William Rehnquist had anaplastic thyroid cancer. After reading this overview page on thyroid cancer, click here to read more about Chief Justice William Rehnquist and his classic battle with the worst kind of thyroid cancer.

What's the Prognosis?
Most thyroid cancers are very curable. In fact, the most common types of thyroid cancer (papillary and follicular) are the most curable. In younger patients, both papillary and follicular cancers have a more than 97% cure rate if treated appropriately. Both papillary and follicular cancers are typically treated with complete removal of the lobe of the thyroid that harbors the cancer, in addition to the removal of most or all of the other side.

The bottom line is that most thyroid cancers are papillary thyroid cancer, and this is one of the most curable cancers of all cancers that humans get. Treated correctly, the cure rate is extremely high.

Medullary cancer of the thyroid is significantly less common, but has a worse prognosis. Medullary cancers tend to spread to large numbers of lymph nodes very early on, and therefore require a much more aggressive operation than the more localized thyroid cancers, such as papillary and follicular. This cancer requires complete thyroid removal plus a dissection to remove the lymph nodes of the front and sides of the neck.

The least common type of thyroid cancer is anaplastic which has a very poor prognosis. Anaplastic thyroid cancer tends to be found after it has spread and is incurable in most cases. It is very uncommon to survive anaplastic thyroid cancer, as often the operation cannot remove all the tumor. These patients often require a tracheostomy during the treatment, and treatment is much more aggressive than for other types of thyroid cancer--because this cancer is much more aggressive.

What About Chemotherapy?
Thyroid cancer is unique among cancers. In fact, thyroid cells are unique among all cells of the human body. They are the only cells that have the ability to absorb iodine. Iodine is required for thyroid cells to produce thyroid hormone, so they absorb it out of the bloodstream and concentrate it inside the cell.

Most thyroid cancer cells retain this ability to absorb and concentrate iodine. This provides a perfect "chemotherapy" strategy. Radioactive Iodine is given to the patient with thyroid cancer after their cancer has been removed. If there are any normal thyroid cells or thyroid cancer cells remain in the patient's body (and any thyroid cancer cells retaining this ability to absorb iodine), then these cells will absorb and concentrate the radioactive "poisonous" iodine. Since all other cells of our bodies cannot absorb the toxic iodine, they are unharmed. The thyroid cancer cells, however, will concentrate the poison within themselves and the radioactivity destroys the cell from within. No sickness. No hair loss. No nausea. No diarrhea. No pain.

Most, but not all, patients with thyroid cancer need radioactive iodine treatments after their surgery. This is important to know. Almost all, however, should have the iodine treatment if a cure is to be expected.

Patients with medullary cancer of the thyroid usually do not need iodine therapy because medullary cancers almost never absorb the radioactive iodine. Some small papillary cancers treated with a total thyroidectomy may not need iodine therapy as well, but for a different reason.

These cancers (medullary and some small papillary cancers) are often cured with simple (complete) surgical therapy alone. This varies from patient to patient and from cancer to cancer. This decision will be made between the surgeon, the patient, and the referring endocrinologist or internist. Remember, radioactive iodine therapy is extremely safe. If you need it, take it.

Overview of Typical Thyroid Cancer Treatment

1. Thyroid cancer is usually diagnosed by sticking a needle into a thyroid nodule or removal of a worrisome thyroid nodule by a surgeon.
2. The removed thyroid nodule is looked at under a microscope by a pathologist who will then decide if the nodule is benign (95-99% of all nodules that are biopsied) or malignant (less than 1% of all nodules, and about 1-5% of nodules that are biopsied).
3. The pathologist decides the type of thyroid cancer: papillary, follicular, mixed papilofollicuar, medullary, or anaplastic.
4. The entire thyroid is surgically removed; sometimes this is done during the same operation where the biopsy takes place. He/she will assess the lymph nodes in the neck to see if they also need to be removed. In the case of anaplastic thyroid cancer, your doctor will help you decide about the possibility of a tracheostomy.
5. About 4-6 weeks after the thyroid has been removed, the patient will undergo radioactive iodine treatment. This is very simple and consists of taking a single pill in a dose that has been calculated for the patient. The patient goes home and avoids contact with other people for a couple of days (so they are not exposed to the radioactive materials).
6. A week or two after the radioactive iodine treatment the patient begins taking a thyroid hormone pill. No one can live without thyroid hormone, and if the patient doesn't have a thyroid anymore, he or she will take one pill per day for the rest of their life. This is a very common medication (examples of branded drug names include Synthroid, Levoxyl, and Armour Thyroid).
7. Every 6-12 months the patient returns to his endocrinologist for blood tests to determine if the dose of daily thyroid hormone is correct and to make sure that the thyroid tumor is not coming back. The frequency of these follow up tests will vary greatly from patient to patient. Endocrinologists are typically quite good at this and will typically be the type of doctor that follows this patient long-term.