Thyroid cancer - papillary carcinomaDefinition:
Papillary carcinoma of the thyroid is the most common cancer of the thyroid gland.
Papillary carcinoma of the thyroid
Causes, incidence, and risk factors:
About 80% of all thyroid cancers diagnosed in the United States are the papillary carcinoma type. This type of cancer is more common in women than in men. It may occur in childhood, but is most often seen in adults between ages 30 and 50.
The cause of this cancer is unknown. A genetic defect may be involved.
Radiation increases the risk of developing thyroid cancer. Exposure may occur from:
- High-dose external radiation treatments to the neck, especially during childhood, used to treat childhood cancer or some non-cancerous childhood conditions
- Radiation exposure from nuclear plant disasters
Radiation given through a vein (through an IV) during medical tests and treatments does not increase the risk of developing thyroid cancer.
Thyroid cancer usually begins as a small lump (nodule) in the thyroid gland, which is located at the center of the front of the neck.
While some small lumps may be cancer, most (90%) thyroid nodules are harmless and are not cancerous.
Most of the time, there are no other symptoms.
Signs and tests:
If you have a lump on your thyroid, your doctor will order blood tests and possibly an ultrasound of the thyroid gland.
If the ultrasound shows that the lump is bigger than 1.0 centimeter, a special procedure called a fine needle aspiration biopsy (FNAB) will be performed. This test helps determine if the lump is cancerous.
Thyroid function tests are usually normal in patients with thyroid cancer.
There are three types of thyroid cancer treatment:
- Radioactive iodine
Surgery is done to remove as much of the cancer as possible. The bigger the lump, the more of the thyroid gland must be removed. Often, the entire gland is taken out.
After the surgery, most patients receive radioactive iodine, which is usually taken by mouth. This substance kills any remaining thyroid tissue. It also helps make medical images clearer, so doctors can see if there is any cancer left behind or if it comes back later.
If surgery is not an option, external radiation therapy can be useful.
After surgery or radioactive iodine, patients will need to take medication called levothyroxine sodium for the rest of their life. This replaces the hormone the thyroid would normally make.
Most patients who had thyroid cancer need to have a blood test every 6 - 12 months to check thyroid levels. Other follow-up tests that may done after treatment for thyroid cancer include:
The survival rate for papillary thyroid cancer is excellent. More than 95% of adults with this cancer survive at least 10 years. The prognosis is better for patients who are younger than 40 and for those with smaller tumors.
The following factors may decrease the survival rate:
- Age over 45
- Cancer that has spread to distant parts of the body
- Cancer that has spread to soft tissue
- Large tumor
- Accidental removal of the parathyroid gland, which helps regulate blood calcium levels
- Damage to a nerve that controls the vocal cords
- Spreading of cancer to lymph nodes (rare)
- Spreading of cancer to other sites (metastasis )
Calling your health care provider:
Call your health care provider if you have a lump in your neck.
Ladenson P, Kim M. Thyroid. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 244.
National Comprehensive Cancer Network. NCCN Guidelines in Oncology 2010: Thyroid Cancer. Version 1.2010.