Thyroid Cancer

Signs & symptoms

The most common symptom of thyroid cancer is a lump, or nodule, that can be felt in the thyroid gland or neck. Other symptoms are rare.

Pain is seldom an early warning sign of thyroid cancer. You may have a tight or full feeling in the neck, difficulty breathing or swallowing, hoarseness or swollen lymph nodes.

Diagnosis

Your doctor may use several tests to learn the size and location of a thyroid nodule or to help determine if a lump is benign, meaning not cancerous, or malignant, meaning cancerous. Your doctor may order blood tests to check how well your thyroid is functioning.

Ultrasonography is a technique that produces a picture of the thyroid. In this procedure, high-frequency sound waves, which cannot be heard by humans, pass through the thyroid. The patterns of echoes produced by these waves are converted into a picture or sonogram by a computer. Doctors can tell if nodules are fluid-filled cysts, which are usually benign, or solid lumps that might be malignant.

A radioactive iodine scan can outline abnormal areas of the thyroid. Before the scan, you are given a very small amount of a radioactive substance, usually technetium (Tc-99m), which collects in the thyroid. An instrument called a scanner can detect areas in the thyroid that don't absorb iodine normally. Because such "cold spots" can be either benign or malignant, further tests are necessary.

Biopsy, or studying tissue samples under a microscope, is the only sure way to determine if you have thyroid cancer. There are two ways to obtain a sample of thyroid tissue — by withdrawing cells using a needle, called a needle biopsy, or by surgically removing the nodule, called a surgical biopsy. In either case, a pathologist examines the tissue to look for cancer cells.

If the needle biopsy does not detect cancer, your doctor may recommend a surgical biopsy or give you thyroid hormone. Thyroid hormones make it unnecessary for the thyroid to produce its own hormones. The gland, including the nodule, may shrink and become inactive. If the thyroid hormone is not effective, surgical biopsy may be performed.

Treatments

Surgery

Surgery is standard treatment for cancer of the thyroid. A doctor may remove the cancer using one of the following operations:

• Total thyroidectomy removes the entire thyroid and is the most common operation recommended.
• Thyroid lobectomy removes one lobe of the gland and may be appropriate for select small, slow growing cancers.
• Lymph node dissection removes lymph nodes in the neck that contain cancer.

Radiation therapy

Radiation therapy uses high-energy X-rays to kill cancer cells and shrink tumors. Radiation for cancer of the thyroid usually comes from drinking a liquid that contains radioactive iodine. Because the thyroid takes up iodine, the radioactive iodine collects in any thyroid tissue remaining in the body and kills the cancer cells. Radiation from a machine outside the body may be given for some advanced tumors after surgery.

Hormone therapy

Hormone therapy uses thyroid hormone to stop cancer cells from growing. In treating cancer of the thyroid, thyroid hormone can be used to stop the body from making other hormones that might make cancer cells grow. Thyroid hormones are usually given as a pill taken once a day.

Chemotherapy

Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be taken by pill, or it may be put into the body by a needle in the vein or muscle. Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body and can kill cancer cells outside the thyroid.