Causes and Treatment of Thyroid Cancer

What do doctors call this condition?

Thyroid carcinoma

What is this condition?

Cancer of the thyroid gland - an endocrine gland in the front of the neck - occurs in all age-groups, especially in persons who have had radiation treatment to the neck area.

Papillary and follicular carcinoma are the most common types of thyroid cancer. Papillary carcinoma is the least aggressive form of thyroid cancer. Follicular carcinoma is less common but more likely to recur and spread to regional lymph nodes and through blood vessels into the bones, liver, and lungs. Giant and spindle cell cancers are seldom curable with surgery. These tumors tend to resist radiation and spread rapidly.

What causes it?

Predisposing factors include radiation exposure, prolonged stimulation of thyroid-stimulating hormone (a substance secreted by the pituitary gland) through radiation or heredity, family predisposition, and chronic goiter (enlarged thyroid).

What are its symptoms?

The most common signs and symptoms of thyroid cancer are a painless nodule (mass), a hard nodule in an enlarged thyroid gland, or lymph nodes that can be felt by palpation (touch), and an enlarged thyroid. Eventually, the pressure of such a nodule or enlargement causes hoarseness, difficulty swallowing, shortness of breath, and pain on palpation. If the tumor is large enough to destroy the gland, thyroid hormone deficiency follows, accompanied by symptoms of low metabolism - mental apathy and sensitivity to cold. However, if the tumor causes excessive production of thyroid hormone, symptoms include sensitivity to heat, restlessness, and hyperactivity.

Other symptoms of thyroid cancer include diarrhea, appetite loss, irritability, and inability to speak (from vocal cord paralysis).

How is it diagnosed?

The first clue to thyroid cancer is usually an enlarged node that you can feel in the thyroid gland, neck, lymph nodes of the neck, or vocal cords. The doctor also will ask if the person has a history of radiation therapy or a family history of thyroid cancer because these factor­support the diagnosis.

Before confirming thyroid cancer, the doctor must rule out non­cancerous thyroid enlargements, which are much more common. A thyroid scan can determine if the node is functional (which is rarely malignant) or hypofunctional (which is commonly malignant).

Other tests include needle biopsy (removal and analysis of thyroid tissue), computed tomography scan (commonly called a CAT scan) ultrasound, chest X-ray, and certain lab tests (such as serum alkaline phosphatase and serum calcitonin assay).

How is it treated?

Treatment of thyroid cancer may consist of total or partial removal of the thyroid and removal of some lymph nodes. In some cases, the surgeon also must remove some neck tissue. Following thyroid surgery, a person may lose his or her voice and be hoarse for several days.

External radiation therapy is given to people with inoperable cancer and sometimes after surgery.

To increase a person's tolerance of surgery and radiation, the doctor may prescribe drugs that suppress the thyroid, along with an adrenergic blocking agent such as Inderal.

Chemotherapy is given to some people whose symptoms suggest that the cancer has spread to other areas.