Thyroid Cancer Diagnosis

This rise in cases is likely due to the more advanced diagnostic techniques that can spot smaller, random (also known as incidental) thyroid tumors before the cancer progresses. This also means that doctors are able to diagnose thyroid cancer much earlier.

Thyroid cancer begins in the thyroid, a gland that is located at the front of the neck, just below the voice box (larynx). This butterfly-shaped gland is part of the endocrine system and controls the release of important chemicals and hormones to the body.

There are three main types of thyroid cancer. They include:

• Well-differentiated: This type makes up the majority of thyroid cancers. Subtypes include:
  • Papillary. Papillary cancer is the most common type, with about 8 in 10 thyroid cancers being papillary cancers. Papillary cancer grows very slowly and appears in just one lobe of the thyroid gland. Because of its slow growth, papillary cancer tend to spread to the lymph nodes in the neck. Papillary cancer can be treated very successfully and is rarely fatal.
  • Follicular. Follicular cancer is the second most common type, making up about 10 to 15% of thyroid cancers. It is a bit more aggressive than papillary cancer, and older patients are at higher risk for developing lung and bone metastases.
  • Hürthle cell. This very rare type of follicular thyroid cancer that makes up only 3% of thyroid cancers.

• Medullary: About 4% of thyroid cancers are medullary. There are two types of medullary thyroid cancer:
  • Sporadic. The more common of the two (about 8 in 10 patients who have medullary thyroid cancer are sporadic). Sporadic cancer is not an inherited condition and does not run in families.
  • Familial. This inherited type of thyroid cancer often develops earlier in a person’s life and can affect both lobes of the thyroid. This type is also associated with other types of tumors.

• Anaplastic: A much more rare, aggressive type of thyroid cancer. Also called undifferentiated thyroid cancer, anaplastic cancer makes up about 2% of all thyroid cancers. It spreads quickly and is very difficult to treat.

There are several signs and symptoms of thyroid cancer. These can include:

• Swelling of the thyroid gland
• Swelling on or around the neck
• A lump on the side of the neck
• Difficulty breathing
• Difficulty swallowing
• Change or sudden hoarseness in the voice

There are several ways to confirm a thyroid cancer diagnosis. If a patient has any of the above signs and symptoms, your care team may use one or more of the following thyroid cancer diagnosis tests and procedures:

• Physical exam. A doctor will feel the thyroid gland for lumps and nodules. The neck and lymph nodes will also be examined for growth and swelling.
• Ultrasound. Sound waves are used to create pictures of the thyroid and nodules that may be too small to be felt by a doctor. Ultrasound is the most common method used to image the thyroid and lymph nodes and can be used to check suspected nodules for irregularities. However, ultrasound is not sensitive enough on its own to confirm a cancer diagnosis, which is why a fine-needle biopsy most often follows or is performed under the guidance of ultrasound.
• Cross Sectional Imaging. While ultrasound is the most common, and typically the most effective, imaging modality associated with thyroid cancer, cross sectional techniques such as MRI, CT and FDG PET scans can be used as well, especially in cases where nodules are indeterminate under ultrasound or biopsy.
• Biopsy. If a nodule on your thyroid is suspected to be cancerous, your doctor will perform a fine-needle biopsy by inserting a small needle into the and removing a sample of cells. These cells are sent to the lab and examined under microscope. Results can be benign, malignant or indeterminate. Indeterminate biopsies can be sent for additional molecular testing for risk assessment for cancer.
• Radioiodine scan. A small amount of radioactive iodine is swallowed or injected. Once it is absorbed, a special camera is used to see what areas light up with radioactivity. Radioiodine scans are typically used in people who have already been diagnosed with differentiated thyroid cancer (papillary, follicular or Hürthle cell) to detect any spreading. (This scan is not used for medullary thyroid cancer, because medullary cancer cells do not absorb iodine.)

These are often done in combination for accurate staging of thyroid cancer.