Thyroid cancer Health Article

Definition

Thyroid cancer is a cancerous growth of the thyroid gland.

Alternative Names

Tumor - thyroid; Cancer - thyroid

Causes, incidence, and risk factors

Thyroid cancer can occur in all age groups.

People who have had radiation therapy to the neck are at higher risk. This therapy was commonly used in the 1950s to treat enlarged thymus glands, adenoids and tonsils, and skin disorders. People who received radiation therapy as children have a higher incidence of thyroid cancer.

Other risk factors are a family history of thyroid cancer and chronic goiter. The disease affects 1 in 1,000 people.

There are several types of thyroid cancer:

• Anaplastic carcinoma (also called giant and spindle cell cancer) is the most dangerous form of thyroid cancer. It is rare, but does not respond to radioiodine therapy. Anaplastic carcinoma spreads quickly and invades nearby structures such as the trachea, causing breathing difficulties.
• Follicular carcinoma accounts for about 30% of all cases and is more likely to come back and spread.
• Medullary carcinoma is a cancer of non-thyroid cells in the thyroid gland and tends to occur in families. It requires different treatment than other types of thyroid cancer.
• Papillary carcinoma is the most common type, and usually affects women of childbearing age. It spreads slowly and is the least dangerous type of thyroid cancer.

Symptoms

• Cough or cough with bleeding
• Difficulty swallowing
• Enlargement of the thyroid gland
• Hoarseness or changing voice
• Neck swelling
• Thyroid lump (nodule)

Note: Symptoms may vary depending on the type of thyroid cancer

Signs and tests

A physical examination can reveal a thyroid mass or nodule (usually in the lower part of the front of the neck), or enlarged lymph nodes in the neck.

Tests for thyroid cancer:

• Elevated serum calcitonin (for medullary cancer) or serum thyroglobulin (for papillary or follicular cancer)
• Laryngoscopy showing paralyzed vocal cords
• Thyroid biopsy showing anaplastic, follicular, medullary, or papillary cancer cells
• Thyroid scan showing a nodule that does not light up on the scan (cold nodule)
• Ultrasound of the thyroid showing a nodule

This disease may also affect the results of the following tests:

• T3
• T4
• TSH