Thyroid Cancer
This page was last updated on: October 4, 2014
What is thyroid cancer?

Cancer of the thyroid is a cancer that forms in the thyroid gland which is an organ at the base of the throat that makes hormones.  These thyroid hormones help control heart rate, blood pressure, body temperature, and weight.

Based on how thyroid cancer looks under the microscope, it has been divided into four types:

- PAPILLARY
- FOLLICULAR
- MEDULLARY
- ANAPLASTIC

Each year in the United States, more than 25,000 women and 8,000 men learn they have thyroid cancer.
The estimated number of new cases in 2008 rose to 37,340 and 1,590 deaths were recorded

Growths on the thyroid are often called nodules. More than 90% of thyroid nodules are benign (not cancerous).

Benign nodules
- are rarely a threat to life
- don't invade the tissues around them
- don't spread to other parts of the body
- usually don't need to be removed

Malignant nodules (Cancerous nodules)
- may sometimes be a threat to life
- can invade nearby tissues and organs
- can spread to other parts of the body
- often can be removed or destroyed, but sometimes the cancer returns

What is metastasis?

Cancer cells can spread by breaking away from the original tumor. They enter blood vessels or lymph vessels, which branch into all the tissues of the body. The cancer cells attach to other organs and grow to form new tumors that may damage those organs. The spread of cancer is called metastasis.


The thyroid gland is located in the anterior portion of the neck, between the larynx (voice box or Adam's apple) and the notch of the sternum (breastbone).
It is shaped like the letter H and resembles the HONDA logo. It has two lobes, one on each side of the trachea (windpipe) and a bridge that connects them, called isthmus.
Symptoms

Early thyroid cancer often does not have symptoms. But as the cancer grows, symptoms may include:

- A lump (nodule) in the front of the neck
- Hoarseness or voice changes
- Swollen lymph nodes in the neck
- Trouble swallowing or breathing
- Pain in the throat or neck that does not go away

Most often, these symptoms are not due to cancer. An infection, a benign goiter, or another health problem is usually the cause of these symptoms. Anyone with symptoms that do not go away in a couple of weeks should see a doctor to be diagnosed and treated as early as possible.

Diagnosis

If you have symptoms that suggest thyroid cancer, your doctor will help you find out whether they are from cancer or some other cause. Your doctor will ask you about your personal and family medical history. You may have one or more of the following tests:

Physical exam: Your doctor feels your thyroid for lumps (nodules). Your doctor also checks your neck and nearby lymph nodes for growths or swelling.


Blood tests: Your doctor may check for abnormal levels of thyroid-stimulating hormone (TSH) in the blood. Too much or too little TSH means the thyroid is not working well. If your doctor thinks you may have medullary thyroid cancer, you may be checked for a high level of calcitonin and have other blood tests.


Ultrasound: An ultrasound device uses sound waves that people cannot hear. The device aims sound waves at the thyroid, and a computer creates a picture of the waves that bounce off the thyroid. The picture can show thyroid nodules that are too small to be felt. The doctor uses the picture to learn the size and shape of each nodule and whether the nodules are solid or filled with fluid. Nodules that are filled with fluid are usually not cancer. Nodules that are solid may be cancer.


Thyroid scan: Your doctor may order a scan of your thyroid. You swallow a small amount of a radioactive substance, and it travels through the bloodstream. Thyroid cells that absorb the radioactive substance can be seen on a scan. Nodules that take up more of the substance than the thyroid tissue around them are called "hot" nodules. Hot nodules are usually not cancer. Nodules that take up less substance than the thyroid tissue around them are called "cold" nodules. Cold nodules may be cancer.

CT scan or MRI: Sometimes, a CT scan is needed to determine whether the cancer has invaded the trachea and to visualize the extent of lymph node involvement. Occasionally, MRI is also used to evaluate the spread of thyroid cancer.

Biopsy: A biopsy is the only sure way to diagnose thyroid cancer. A pathologist checks a sample of tissue for cancer cells with a microscope.
Your doctor may take tissue for a biopsy in one of two ways:

Fine-needle aspiration (FNA): Most people have this type of biopsy. Your doctor removes a sample of tissue from a thyroid nodule with a thin needle. An ultrasound device can help your doctor see where to place the needle.

Surgical biopsy: If a diagnosis cannot be made from fine-needle aspiration, a surgeon removes the whole nodule during an operation. If the doctor suspects follicular thyroid cancer, surgical biopsy may be needed for diagnosis.


Adapted from the National Cancer Institute and the National Institute of Health.
Otolaryngology Houston

Bechara Y. Ghorayeb, MD
Otolaryngology - Head & Neck Surgery
Memorial Hermann Professional Building
1140 Business Center Drive, Suite  560
Houston, Texas 77043
For appointments, call: 713 464 2614