Cancer of the Thyroid Gland

The thyroid gland, located in the neck, plays an important role in metabolism. Cancer of the thyroid gland is uncommon, accounting for only about 1 percent of all cancers in the United States each year. Fortunately, thyroid cancer is often curable.

The thyroid gland is located in the bottom half of the neck, just in front of the windpipe and below the Adam's apple. The gland is shaped almost like the figure eight, having two rounded "lobes" with a small, tube-like "isthmus" connecting the two lobes.

The function of the thyroid gland is to aid in metabolism. It uses iodine from the food we eat to help make thyroid hormone. In fact, iodine deficiency (uncommon in the United States) can cause a low thyroid state, resulting in mental retardation and short stature in children, or fatigue and slowed thinking in adults.

The most common way thyroid cancer is detected is when a patient or your physician notices a lump in the neck in the area of the thyroid gland. The overwhelming majority of these "lumps" are benign and not cancerous. Lumps in the thyroid gland can have numerous causes, ranging from infection to benign growths.

At times, lumps in the neck are due to benign tumors that secrete excess thyroid hormone, resulting in a disease state known as hyperthyroidism (too much thyroid hormone). The symptoms of high thyroid hormone levels are the opposite of low thyroid hormone levels (hypothyroidism). Instead of feeling slow and apathetic, patients often feel anxious and nervous.

If a lump is detected in your thyroid gland, your physician will want to investigate its cause. Your doctor will ask you about your medical history and do a physical exam. There are some aspects of a person's history that make a thyroid cancer more likely. Although women are much more likely to have thyroid disease and thus, thyroid cancer, an individual lump in a man has a higher chance of being cancerous.

A history of radiation exposure is a strong risk factor for thyroid cancer. Radiation was used many years ago (before its risks were known) for the treatment of many common conditions (including acne). The incidence of thyroid cancer increased markedly in the local Russian population after they were exposed to radiation during the Chernobyl incident.

Other suspicious characteristics of a thyroid lump include a rapid enlargement and a rock-hard consistency of the lump (benign lumps are usually soft or rubbery in consistency). A single lump is more suspicious for cancer than multiple lumps or enlargement of the whole gland.

After the history and physical, several tests may be ordered to determine the cause of the lump or "mass." This often includes basic blood tests and special x-ray studies.

The definitive test to determine the cause of a thyroid mass is to take the lump out and examine it under the microscope. Before open surgery, often a person will be asked to undergo a needle-aspiration biopsy. This involves putting a needle through the skin and into the thyroid lump to take a tiny piece of it.

The piece is sent to a pathologist, who looks at the tissue under the microscope and decides whether or not the mass is a cancer. If the pathologist thinks the mass is a cancer or cannot tell whether or not cancer is present, surgery is usually performed.

Surgery for a thyroid lump is relatively minor and involves making a small incision in the neck and cutting out the mass - usually one half (or one lobe) of the thyroid gland is removed. Surgery is curative for at least 75 percent of thyroid cancers and leaves few residual problems other than a small scar from the surgical incision. After surgery, some people are advised to get a special form of anticancer treatment.

This treatment, known as "radioactive iodine ablation," exploits the fact that the thyroid gland concentrates iodine in the body. Iodine, attached to radioactive substances, is injected into the body. The iodine is taken up preferentially into thyroid tissue, destroying it. This treatment can be used to treat the primary tumor as well as any spread of the cancer to other areas of the body.

Overall, thyroid cancer has a very high survival rate - 90 percent of people diagnosed with thyroid cancer are still alive ten years later. While an uncommon form of cancer, thyroid cancer is often detectable early because of its location close to the skin. If you notice a lump in your neck, see your physician to have it evaluated.

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