Types of Thyroid Cancer

There are four major types of thyroid cancer some of which are much more common than others. How these cancers are treated, how much surgery is necessary, and whether or not radioactive iodine, targeted chemotherapy, or other therapies are needed depends on which type of thyroid cancer is present. The only way to determine which type of thyroid cancer is present is to perform a biopsy. The type of cancer is defined by the type of cells that make up the cancer and this is determined under a microscope by a pathologist. To read more about this process, see our page on Needle Biopsy of Thyroid Nodules. The type of thyroid cancer present is so important, that the person with thyroid cancer must understand these differences. Calling it “thyroid cancer” is not accurate enough, we really must be more specific because everything we do is determined by which type of thyroid cancer is present. We have made a special section of this website for each of these different cancer types.

Thyroid Cancer Types and Incidence


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What's the Prognosis of Thyroid Cancer?

We have very detailed prognosis information for all of the thyroid cancer types on different parts of this website. But as an introduction to thyroid cancer, you should know that most thyroid cancers are very curable. In fact, the most common types (papillary thyroid cancer and follicular thyroid cancer) are the most curable. In younger patients, both papillary and follicular cancers can be expected to have better than 97% cure rates when treated appropriately. What is critically important, is that the initial surgery for any thyroid cancer must be the most complete surgery as possible. What this means is that “incomplete” surgery (unfortunately this is very common) :
  1. compromises the ability to control disease
  2. causes the need for additional surgery
  3. increases the risks of further surgery
  4. potentially compromises survival.

Both papillary and follicular cancers are typically treated with complete removal of the lobe of the thyroid which harbors the cancer. Many will require removal of most or all of the other side of the thyroid. The bottom line, most thyroid cancers are papillary thyroid cancer, and this is one of the most curable cancers of all cancers that humans get, provided you are cared for by thyroid surgeons who have an expertise in treating thyroid cancer. As we often tell our patients, if you must choose a type of cancer to have, papillary cancer would be your choice. Have an expert doctor who treats it correctly and the cure rate is extremely high!

Follicular thyroid cancer frequently cannot be diagnosed until following surgery. The reason why this is so is because when you examine the cells under a microscope obtained by fine needle aspiration (FNA) of non-cancerous (benign) follicular thyroid nodules such as follicular adenomas, hurthle cell tumors, and follicular hyperplasia are indistinguishable from follicular thyroid cancers. Only upon removal of follicular thyroid cancers can pathologists determine whether the follicular cells are malignant since they have to visualize the follicular thyroid cancer cells microscopically growing into the capsule of the nodule or blood vessels surrounding the thyroid growth. Once again, you may possess a favorable thyroid cancer but you must also choose the right surgeon to perform the right and complete surgery required for your “at risk” disease.

Medullary thyroid cancer is significantly less common, but has a worse prognosis. Medullary thyroid cancer can occur spontaneously in patients or be genetically inherited. Medullary cancers tend to spread to large numbers of lymph nodes very early on, and therefore requires a much more extensive operation than does the more localized cancers such as papillary and follicular. This cancer requires complete thyroid removal plus a dissection to remove the lymph nodes of the front and sometimes the 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 not cured in most cases (it is very uncommon to survive anaplastic thyroid cancer). Rarely can a meaningful operation be performed unless all of the anaplastic thyroid cancer can be completely removed and there is no evidence of distant spread of the cancer. Anaplastic thyroid cancer is one of the deadliest of all cancers known to mankind. These patients often require a palliative symptom management during their treatment. Treatment of anaplastic thyroid cancer is much more aggressive than for other types of thyroid cancer and frequently includes chemotherapy, radiation therapy and targeted therapy--because this cancer is so much more aggressive.

Much more details are provided in the specific pages for each thyroid cancer type.