What Is Papillary Carcinoma of the Thyroid?
The thyroid gland is shaped like a butterfly and sits above your collarbone at the center of your neck. Its function is to secrete hormones that help to regulate your metabolism and growth.
If you feel any unusual lumps on your neck, call your doctor, as this may signal a problem with your thyroid. Most of the time, the lump will be benign and harmless—a simple build-up of excess thyroid cells that have formed a mass of tissue. Sometimes, however, the lump is papillary carcinoma of the thyroid.
Papillary carcinoma of the thyroid is the most common type of thyroid cancer. According to the University of Maryland Medical Center, it comprises approximately 80 percent of thyroid cancers. This cancer can be diagnosed at any age, but is mostly seen in adults over the age of 45.
Papillary carcinoma of the thyroid is a slow-growing cancer, and typically develops in only one lobe of the thyroid gland. When caught in its early stages, this cancer has a very high survival rate and most sufferers are cured.
What Are the Causes of This Cancer?
The exact cause of papillary carcinoma of the thyroid is unknown. There may be a genetic mutation involved, but more research is necessary to confirm this hypothesis.
One risk factor for the disease is exposure to radiation treatments on the neck. Adults who were exposed to radiation treatments as a child are especially at risk.
Symptoms of Papillary Carcinoma of the Thyroid
Generally, this cancer is asymptomatic. You might feel a lump on your thyroid, but most nodules on the thyroid are not cancerous. If you do feel a lump, call your doctor. He or she will be able to give you an exam and order appropriate diagnostic tests, if necessary.
Testing for and Diagnosing Papillary Thyroid Cancer
Papillary carcinoma of the thyroid can be diagnosed using a variety of tests. A clinical exam will be done first to check for any swelling of the thyroid gland and nearby tissues.
Blood tests may be ordered to check levels of thyroid-stimulating hormone (TSH). TSH is the hormone the pituitary gland produces, which stimulates the release of thyroid hormone. Too much or too little TSH is cause for concern.
An ultrasound of the thyroid gland may also be performed. This imaging test will allow your doctor to see the shape and size of the thyroid, detect any nodules and determine if they are solid masses or filled with liquid. Liquid-filled nodules are typically not cancer, while solid ones have a greater chance of being malignant.
Your doctor may also want to do a thyroid scan. For this scan, you will swallow a small quantity of radioactive dye that will be taken up by some of the thyroid cells. Looking at the nodule area on the scan, your doctor will see whether it is “hot” or “cold.” Hot nodules are those that take up more of the dye than the surrounding thyroid tissue; these are not usually cancerous. Cold nodules do not take up as much of the dye, as the surrounding tissues and less like to be benign although only a small percentage is proven to be cancerous (AAES).
A biopsy may be performed to acquire a small piece of tissue from the thyroid. This tissue can then be examined microscopically to make a definitive diagnosis of cancer. It can also be used to diagnose which type of thyroid cancer is present. The biopsy may be done with a needle (fine needle aspiration), or with surgery if a larger sample is needed. During surgery, your doctor will often remove a larger portion of the thyroid; he may even remove the entire thyroid if necessary.
Talk to your doctor before the biopsy (or other testing) if you have any concerns or questions. The doctor should explain to you before any surgery what, if any, chronic medications might be required as a result of the surgery.
Staging Papillary Thyroid Cancer
Once a diagnosis has been made, the cancer will then be staged. Staging is the term used for how doctors categorize the severity of a disease and the treatment needed. Staging for thyroid cancer is different than for other cancers. There are still stages I through IV, in ascending severity, but staging also takes into consideration the patient’s age and the subtype of thyroid cancer. Staging for papillary thyroid cancer is as follows (ACS, 2012):
Patients Under 45 Years Old
Stage I: In this stage, the tumor is any size, may be in the thyroid, and may also have spread to nearby tissue and lymph node. The cancer has not spread to other parts of the body.
Stage II: In this stage, the tumor is any size, and the cancer has already spread to some other part of the body, such as the lungs or bone. It may have spread to lymph nodes as well.
Note: There is no Stage III or IV for papillary thyroid cancer patients under 45.
Patients Over 45 Years Old
Stage I: In this stage, the tumor is under 2 centimeters, and the cancer is only found in the thyroid.
Stage II: In this stage, the tumor is larger than 2 centimeters, but smaller than 4 centimeters. The cancer is still only found in the thyroid.
Stage III: Either A) the tumor is over 4 centimeters and only in the thyroid, or the tumor is any size and the cancer has spread to nearby tissue but not to lymph nodes; or B) the tumor is any size and the cancer has spread to nearby tissues AND to lymph nodes near the trachea or larynx
Stage IV: Stage IV is more complicated. It is divided into three sub-stages: IVA, IVB, and IVC:
- In stage IVA, either A) the tumor is any size and the cancer has spread to tissue under the skin, the trachea, the esophagus, the larynx, and/or the recurrent laryngeal nerve—the cancer may also have spread to nearby lymph nodes; or B) the tumor is any size, the cancer has spread to nearby tissue, and the cancer has spread to lymph nodes on one or both sides of the neck or between the lungs.
- In stage IVB, the cancer has spread to tissue in front of the spinal column, or around the carotid artery, or the blood vessels between the lungs. Cancer may also have spread to the lymph nodes.
- In stage IVC, the tumor is any size, and the cancer may have spread to any other part of the body, including lungs, bones, and lymph nodes.
Treatment for Papillary Carcinoma of the Thyroid
According to the National Cancer Institute, the typical treatment for papillary thyroid cancer includes surgery, thyroid hormone treatment, and radioactive iodine therapy (NCI). Other types of treatment like chemotherapy and external radiation are usually used in other subtypes of cancer.
In thyroid cancer surgery, you may have part or all of your thyroid gland removed. This is done through an incision in the neck when you are under sedation. Once the surgery is complete, you may have to take supplemental thyroid hormones for the rest of your life.
Thyroid hormone treatment involves use of thyroid hormone pills. Aside from being a necessary replacement for naturally occurring thyroid hormones, they can also slow down the growth of any thyroid cancer cells that remain in your body after surgery.
Radioactive Iodine Therapy
Radioactive iodine therapy involves the consumption of the radioactive material I-131. Prior to the therapy, you will have to follow a low-iodine diet for a few weeks. Tell your doctor also if you have had any computed tomography (CT) scans during the six months before therapy, as some imaging tests use iodine in the contrast materials. The I-131 medication is given as a liquid or capsule, and so this therapy can typically be done in an outpatient setting. The I-131 travels to the thyroid cancer cells, and when these cells fill to their limit of I-131, they will die. Most of the radioactive part of the drug is gone within a week.
Talk with your doctors about the treatment plan you are on, along with the expected course of treatment, risks and side effects, and long-term plans.
Outlook for Papillary Thyroid Cancer
According to the University of Maryland Medical Center, papillary thyroid cancer has a very good prognosis, with more than 95 percent of patients surviving at least 10 years after their diagnosis (UMM).