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An Introduction to Thyroid Cancer
Overview of Thyoid Cancer Information

by Mary Shomon

Thyroid cancer is not common. Thyroid malignancy accounts for only 1.2% of all new cancers (outside skin cancers) in the United States annually. The thyroid is a butterfly-shaped organ located below the Adam's Apple, at the base of the throat. The thyroid's function is to produce produces hormones that help the body use oxygen and calories for energy, and regulation of metabolism, among many functions.

Prevalence of Thyroid Cancer

Some people refer to thyroid cancer as a "good cancer," primarily because it has very high survival rates. Thyroid cancer is still a cancer that requires treatment and lifelong monitoring, however, and can have debilitating effects on patients. Survival rates, are, however, high, with 95% of all thyroid cancer patients achieving what would be considered a cure, or long-term survival without reoccurrence.

It's estimated that this year, there will be almost 26,000 new cases of thyroid cancer in the U.S. -- 19,190 in women and 6,500 in men -- and an estimated 1,500 people are expected to die of thyroid cancer in 2005. While rare, thyroid cancer is actually one of the few cancers that are becoming more common in the past several years, with a growth rate of 3% per 100,000 people each year.

Who Gets Thyroid Cancer?

Thyroid cancer affects women two to three times more than men. Besides what appears to be a hormonal or gender connection, the causes of thyroid cancer are, for the most part, not known. There is a link between people who received childhood radiation to the head and neck and an increased risk for thyroid cancer. In addition, exposure to nuclear radiation (such as happened during and after the Chernobyl nuclear accident) can also increase the risk of thyroid cancer fairly dramatically. Some forms of thyroid cancer also appear to be hereditary or genetic and run in families.

When Does Thyroid Cancer Appear?

The median age at diagnosis for papillary thyroid cancer is approximately 40 for women, and 45 for men. The average age for onset of follicular cancer is 48 for women and 53 for men. Anaplastic thyroid carcinoma is more common in sixties and seventies, and is more commonly seen in those who have had goiter or a previous case of papillary or follicular thyroid cancer.

Symptoms of Thyroid Cancer

Typically, if there's any symptom at all, it will more likely be a nodule or swelling in the thyroid, although many people are symptomless. Nodules are generally common in the population, however, and do not necessarily indicate cancer. In fact, 95% of thyroid nodules are considered benign - not cancerous. Those who do report symptoms also can note hoarsening of the voice, neck pain / discomfort, difficulty swallowing, and swollen lymph nodes.

Four Types of Thyroid Cancer

There are four types of thyroid cancer: Papillary, Follicular, Medullary, and Anaplastic.
  • About 75% of Thyroid Cancers are Papillary and Papillary/follicular
  • About 15% are Follicular and Hurthle cell
  • About 7% are Medullary
  • About 3% are Anaplastic
By far the most prevalent type of thyroid cancer is papillary, as papillaries are quite common in the thyroid gland. Papillary cancer mostly involves one side of the thyroid and sometimes spreads into the lymph nodes. The cure rate is very high.

Follicular cancer, the second most common type of thyroid cancer, is considered to be somewhat more malignant than papillary. The thyroid gland is comprised of follicles which produce thyroid hormones that are essential for growth and development of all body tissues. This cancer doesn't usually spread to the lymph nodes, but it may spread to arteries and veins of thyroid gland and more distantly (lung, bone, skin, etc), though that is uncommon. Follicular cancer is more common in older people. Again, the long -term survival rate is high.

Medullary thyroid cancer is the third most common type of thyroid cancer, and usually originates in the upper central lobe of the thyroid. It spreads to the lymph nodes earlier than papillary or follicular cancers. It differs from papillary and follicular cancer, however, in that it does not arise from cells that produce thyroid hormone, but instead from C cells. These C cells make the hormone calcitonin. This type of cancer can run in families, and also has a good cure rate.

Anaplastic is the rarest and most serious thyroid cancer. It can spread early to lymph nodes, thus usually the cause for a visit to the doctor is a mass in the neck. It also is the form of thyroid cancer most likely to spread to other organs beyond the thyroid or lymph nodes. This type of thyroid cancer is more common in those over 65 and in men. Long-term survival rates are far less than for the other three types of cancer.

Treatments

Some patients and doctors view thyroid cancer differently than other cancers because they're treated and handled fairly differently than other cancers. For example, chemotherapy is rarely used as a treatment for thyroid cancer. Generally, surgery is the most common treatment. Usually a fairly short surgery, (unless lymph nodes are also involved) it is sometimes even done as a day surgery, or with just one night in the hospital. General anesthesia is usually used, however, there are some surgeons who will perform thyroid surgery with local anesthetics.

Thyroid surgery is not very risky. The main concern is potential damage to the vocal cords or voice box--but this is rare. During surgery, either part or all of the thyroid gland is removed depending upon the level of abnormality.

After surgery, most patients will receive Radioactive Iodine (RAI) treatment. This involves consumption of radioactive iodine, which concentrates in any remaining thyroid tissue, and kills that tissue, targeting the cancer specifically. External radiation therapy is not as common as RAI, and is used when the cancer cannot be totally removed.

Followup

Even after removal of the thyroid gland, in whole or in part, or other types of treatment, most patients will then be classified as hypothyroid, and will need to take prescription thyroid hormone replacement drugs for the remainder of their lives. Most physicians will administer sufficient thyroid hormone so as to suppress the TSH level so that it is nearly undetectable (in the hyperthyroid range), close to 0. This suppression of TSH helps to prevent cancer recurrence.

Many physicians also ask patients to go off thyroid hormone annually and undergo a scan for any recurrence. In some cases, the thyroid drug Cytomel (trioiodothyronine or T3) can be given for part of the time to minimize hypothyroidism symptoms, but in some cases, a patient has to go completely off all thyroid hormone and become hypothyroid, until the scan is completed and evaluated. Frequently, doctors will also recommend those patients go on what's known as the low-iodine diet, a diet that helps ensure the highest possible accuracy of the scan.

Some thyroid cancer survivors who are scheduled for a scan may be eligible to use a drug called Thyrogen, which prevents the symptoms and effects of hypothyroidism, but allows for a scan for recurrence. Thyrogen scans are not considered quite as accurate as full withdrawal from thyroid hormone, but some doctors will perform them for someone who has had several clean scans in a row and who is at lower risk of recurrence.

Thyroid Cancer Survivor's Association
When it comes to specific questions re thyroid cancer diagnosis, treatment, and followup, I always recommend that people go right to the experts, the Thyroid Cancer Survivor's Association (Thyca). Thyca sponsors an annual conference of thyroid cancer survivors. ThyCa's informational website is http://www.thyca.org. The Thyca website features local support groups in many cities you can join, plus an online support group, known as the ThyCA listserv. The Thyca List includes patients who've had thyroidectomies, and surgeons/doctors with expertise! They are the BEST source of information on what to expect from surgery, finding the best surgeons and thyroid cancer specialists, RAI and scans, and just as important, living well after surgery. If you have questions about thyroid cancer, I urge you to join the ThyCa list, and ask your question of the informed patients and doctors on that list.

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Mary Shomon is a nationally-known thyroid patient advocate and best-selling author of numerous books on thyroid disease, including the New York Times best-seller The Thyroid Diet: Manage Your Metabolism for Lasting Weight Loss, Living Well With Hypothyroidism: What Your Doctor Doesn't Tell You...That You Need to Know, the Thyroid Guide to Fertility, Pregnancy and Breastfeeding Success, Living Well With Graves' Disease and Hyperthyroidism (coming Fall 2005)." She is editor of the sticking Out Our Necks Thyroid Newsletter, and the Thyroid Information website at www.thyroid-info.com.

Sticking Out Our Necks and this website are Copyright Mary Shomon, 1997-2005. All rights reserved. Mary Shomon, Editor/Webmaster
All information is intended for your general knowledge only and is not a substitute for medical advice or treatment for specific medical conditions. You should seek prompt medical care for any specific health issues and consult your physician or health practitioner before starting a new treatment program. Please see our full disclaimer.