Thyroid Cancer

Thyroid cancer is by far the most common malignancy affecting the endocrine, or hormone-producing, system. Even so, it is relatively rare, with about 13,000 new cases and 1,000 deaths a year.

Hormones secreted by the thyroid, a butterfly-shaped gland whose two lobes rest over the front of the trachea (windpipe) in the lower neck, regulate metabolism (see Thyroid Disorders). The thyroid gland is highly sensitive to radiation, especially when exposure occurs in a person under age 21. This became evident when studies found a greatly increased incidence of thyroid cancer among people who underwent radiation treatment as children for such disorders as an enlarged thymus, chronic tonsillitis, and even acne, a practice that has been abandoned. About 10 percent of those receiving such treatments later developed thyroid cancer. Similarly, people accidentally exposed to radiation, such as the Marshall Island inhabitants who were under the fallout of an atomic bomb detonated on the atoll Bikini in 1954, also have an increased incidence of thyroid cancer.

For unknown reasons, the course of thyroid cancers varies dramatically according to age. When the malignancy develops before the age of 40 in men and 50 in women, it is rarely fatal, even if it is quite advanced. In contrast, the outlook is poor after the age of 50, with the disease progressing rapidly and resisting treatment.

Thyroid cancer typically starts as a small lump, or nodule, that a doctor can feel when palpating the gland. Sometimes the first obvious sign is an enlarged lymph node in the neck. As the primary thyroid tumor grows, it may encroach on surrounding organs, resulting in possible voice changes, paralysis of the vocal cords, and swallowing problems due to a narrowing of the esophagus.

Diagnostic Studies and Procedures

Most thyroid nodules are benign, but these can be hard to distinguish from those that ate cancerous. A thyroid scan using radioactive iodine can make the distinction, however, because benign, or hot, nodules produce hormones and lend to absorb more of the iodine than nodules that do not make hormones. These so-called cool nodules are more likely to be cancerous, but in either instance, a biopsy is needed to rule out malignancy.

Sometimes what feels like a nodule is actually a cyst, in which case an ultrasound examination may verify that it is. However, some cysts are mixtures of solid and cystic tissue, which can produce misleading results. Thus, only a biopsy can determine whether a thyroid lump is cancerous. This can be done by withdrawing tissue samples from the nodule using a hollow needle.

If cancer is confirmed, a CT scan or MRI may be ordered to detect arty spread to nearby organs. A lung X-ray may also be needed, as some thyroid cancers spread to the lungs.

Medical Treatments

Thyroid cancer is generally treated surgically, but the extent of the operation depends upon the patient's age and type of cancer. Removal of the suspicious nodules, perhaps along with treatment using radioactive iodine, may be enough in a young person. Most experts, however, advise removing half or all of the affected thyroid lobe, especially if the patient is over 50 or the tumor is large and has invaded nearby tissue. Some or all of the opposite lobe may also be removed. When all of the thyroid is removed -- a total thyroidectomy -- lifelong hormone replacement therapy will be needed.

In advanced cases, radiation treatments, either alone or combined with chemotherapy, can alleviate pain and other symptoms. A tracheostomy, an opening in the trachea, or windpipe, may be necessary to allow breathing if the cancer threatens to close the airway.

Occasionally, during surgery to remove the thyroid cancer, the parathyroid glands -- small clusters of tissue in the thyroid that produce hormones for controlling calcium metabolism -- are inadvertently destroyed. If this happens, additional hormone replacement is needed, although an experimental treatment to implant salvaged parathyroid tissue appears promising. Other possible complications of thyroid surgery include damage to the nerves that control the opening of the airway, making a permanent tracheostomy necessary, and speech problems that result from larynx nerve damage.

Alternative Therapies

No effective alternative therapies for thyroid cancer exist, other than meditation, imaging, deep breathing, and other relaxation therapies to control pain and stress.

Self-Treatment

Thyroid cancer itself cannot be self-treated, but preventive measures can be taken. As much as possible, avoid exposing the head and neck to radiation, especially during childhood. Because people with Hashimotos disease, a disorder in which the thyroid is chronically inflamed and gradually destroyed, have an increased risk of thyroid cancer, they should be diligent about having regular examinations.

Other Causes of Thyroid Symptoms

A goiter due to an over- or underactive thyroid can cause swelling of the gland.