Thyroid cancer is the ninth most common cancer in the United States. In 2014, it is estimated that nearly 63,000 Americans will be diagnosed with thyroid cancer, and nearly 1,900 will die of the disease. The overall incidence of this cancer in the United States has increased in people of all racial/ethnic groups and in both males and females over the past several decades.
Thyroid cancer typically doesn’t cause any signs or symptoms early in the disease. As it grows, it may cause:
- A lump that can be felt through the skin on your neck
- Changes to your voice, including increasing hoarseness
- Difficulty swallowing
- Pain in your neck and throat
- Swollen lymph nodes in your neck
If you experience any these signs or symptoms, make an appointment with your doctor. Thyroid cancer isn’t common, so your doctor may investigate other causes of your signs and symptoms first.
There are four types: Papillary, Follicular, Medullary, Anaplastic
1) Papillary Thyroid Cancer (most common)
- Papillary and follicular thyroid cancers are referred to as differentiated thyroid cancer, which means that the cancer cells look and act in some respects like normal thyroid cells.
- Papillary and follicular thyroid cancers account for more than 90% of all thyroid cancers. They tend to grow very slowly.
- Their variants include columnar, diffuse sclerosing, follicular variant of papillary, Hürthle cell, and tall cell. Two other variants (insular andsolid/trabecular) are considered to be intermediate between differentiated thyroid cancer and poorly differentiated thyroid cancer. The variants tend to grow and spread more than typical papillary cancer.
- If detected early, most papillary and follicular cancers can be treated successfully. Their treatment and management are similar and are based on staging and individual risk levels.
- Papillary thyroid cancer is the most common type of thyroid cancer. It accounts for about 80% of all thyroid cancers. Papillary cancer generally grows very slowly, but can often spread to lymph nodes in the neck. It also can spread elsewhere in the body.
- The most common variant of papillary is the follicular variant (not to be confused with follicular cancer). It also usually grows very slowly. Other variants of papillary thyroid cancer (columnar, diffuse sclerosing, and tall cell) are not as common and tend to grow and spread more quickly.
2) Follicular Thyroid Cancer
- Follicular thyroid cancer accounts for about 10-15% of all thyroid cancers. Treatment will be discussed later in this booklet. Hürthle cell thyroid cancer is a variant of follicular.
- Follicular thyroid cancers usually do not spread to the lymph nodes, but in some cases can spread to other parts of the body, such as the lungs or bones.
- Treatment for follicular thyroid cancer is similar to treatment for papillary. Hürthle cell cancer (also known as oncocytic or oxyphilic) is less likely than other differentiated cancer to absorb radioactive iodine, which is often used for the treatment of differentiated thyroid cancer.
- A protein called thyroglobulin (abbreviated Tg) is used as a marker for whether all of the differentiated thyroid cancer has been successfully removed. Determining the Tg level in your blood by periodic testing will help your doctors determine how well you are doing with your treatment. Some patients produce anti-thyroglobulin antibodies (TgAb), which are not harmful but which mask the reliability of the Tg value.
3) Medullary Thyroid Cancer
- Medullary tumors are the third most common of all thyroid cancers. They make up about 3% of all the cases.
- But what are some common medullary thyroid cancer symptoms? Unlike papillary thyroid cancer and follicular thyroid cancer that arise from thyroid hormone producing cells, medullary thyroid cancer originates from the parafollicular cells (also called C cells) of the thyroid.
- These C cells make a different hormone called calcitonin, which has nothing to do with the control of metabolism the way thyroid hormone does. As you will see below, the production of this hormone can be measured after an operation to determine if the cancer is still present and if it is growing.
- This cancer has a much lower cure rate than does the well-differentiated thyroid cancers (papillary and follicular), but cure rates are higher than they are for anaplastic cancer. Overall, 10-year survival rates are 90% when all the disease is confined to the thyroid gland; 70% with spread to cervical lymph nodes; and 20% when spread to distant sites.
4) Anaplastic Thyroid Cancer
- Anaplastic tumors are the least common (only 1% of all thyroid cancer cases) and most deadly of all thyroid cancers. This cancer has a very low cure rate with the very best treatments. Most patients with anaplastic thyroid cancer do not live 1 year from the day they are diagnosed.
- Anaplastic thyroid cancer often arises within a more differentiated thyroid cancer or even within a goiter. Like papillary cancer, anaplastic cancer may arise many years (more than 20) following radiation exposure. Cervical metastasis (the spread of the cancer to lymph nodes in the neck) are present in the vast majority (more than 90%) of cases at the time of diagnosis. The presence of lymph node metastasis in these cervical areas causes a higher recurrence rate and is predictive of a high mortality rate.
- What are some common anaplastic cancer symptoms? The most common way this cancer becomes evident is by you or a family member noticing a growing mass on your neck. When the doctor feels the neck mass, it is usually large and very hard. These tumors grow very rapidly, and you may say that you never noticed it until a few days or weeks ago, and now it seems to get bigger every few days.
- Anaplastic cancer invades adjacent structures and metastasize extensively to cervical lymph nodes and distant organs, such as the lungs and bones. Tracheal invasion is present in 25% at the time of presentation (said differently, in about 25% of cases, the anaplastic cancer has grown out of the thyroid and into the trachea). This is why many patients with anaplastic cancer will need a tracheostomy, while almost nobody with the other types of thyroid cancer will need one.
- Anaplastic cancer that spreads to the lungs is present in 50% of patients at the time of diagnosis. Most of these cancers are so aggressively attached to vital neck structures that they are inoperable at the time of diagnosis. (The surgeon can’t remove it because it’s growing into other neck structures). Even with aggressive therapy protocols, such as hyperfractionated radiation therapy, chemotherapy, and surgery, survival at 3 years is less than 10%.
Being exposed to radiation to the head and neck as a child increases the risk of thyroid cancer. Having certain genetic conditions such as familial medullary cancer, multiple endocrine neoplasia type 2A syndrome, and multiple endocrine neoplasia type 2B syndrome can also increase the risk of thyroid cancer.
The incidence of thyroid cancer is increasing more rapidly than that of any other cancer in the United States. Some, although not all, of this increase can be explained by improved detection methods. This type of cancer incidence rates vary by both sex and race, with incidence being nearly three times higher in women than in men and nearly twice as high in whites as in African Americans. After whites, Asians/Pacific islanders have the second highest incidence. Overall mortality rates remain low despite rising an average of 0.8% annually from 2002-2011.
Most people who develop thyroid cancer are between age 25 and 65 years. Risk factors for this type of cancer include being female, exposure to radiation to the head and neck as a child, exposure to radioactive fallout, a personal history of goiter, a family history of thyroid disease or thyroid cancer, certain genetic conditions, and Asian ancestry. There are no routine screening tests for it. Standard treatments for this include surgery, radiation therapy (including radioactive iodine therapy), chemotherapy, thyroid hormone therapy and targeted therapy.