The thyroid is a small, butterfly-shaped gland at the base of the throat. It has a left and right lobe. The isthmus is the part of the thyroid gland where the lobes connect. The thyroid makes the hormone thyroxine, which helps the body regulate:
• blood pressure
• heart rate
• body temperature
• body weight
Thyroid cancer is the most common type of endocrine cancer. Diagnosis is on the rise in all countries. This may be because it has become easier to find the disease.
Early thyroid cancer has no symptoms. You won’t be able to feel your thyroid gland if it’s healthy. As thyroid cancer progresses, the following symptoms may occur:
• a lump in the throat
• a cough
• pain in the throat and neck
• difficulty swallowing
• swollen lymph nodes in the neck
Talk to your doctor if you have any of these symptoms.
Risk factors for thyroid cancer include:
• having a family history of thyroid cancer
• being a woman
• having a history of breast cancer
• having a history of radiation exposure
Age is also a risk factor. Thyroid cancer is most likely to occur after age 40.
Types of thyroid cancer and incidence
Thyroid cancers are relatively uncommon. In the United States, it’s the tenth most common type of cancer. It’s about one-tenth as common as breast cancer, and one-fifth as common as lung cancer.
Thyroid cancers are classified according to the appearance of the cancerous cells. Cancerous cells that look like healthy cells are called well-differentiated cells. Well-differentiated cells grow at a slower rate than undifferentiated cells.
The types of thyroid cancer include:
Papillary thyroid cancer
Papillary thyroid cancer is a well-differentiated form of thyroid cancer. It’s the most common type. It’s most often seen in women of childbearing age. Papillary thyroid cancer is less dangerous than the other types. It spreads slower, and it’s very treatable.
Medullary thyroid cancer
Medullary thyroid cancer is another well-differentiated form of thyroid cancer. Some cases of medullary thyroid cancer have a genetic component. This can cause it to occur as part of a syndrome of endocrine gland cancers. Cases without a genetic component are said to be “sporadic.”
Medullary thyroid cancer arises in non-thyroid cells located in the thyroid gland. It’s treated differently than other forms of thyroid cancer.
Follicular thyroid cancer
Follicular thyroid cancer is the type of thyroid cancer most likely to spread and recur. Hurthle cell cancer is a type of follicular cancer.
Anaplastic thyroid cancer
Anaplastic thyroid cancer is the most aggressive form of thyroid cancer. It’s rare and difficult to treat.
This is a rare type of thyroid cancer. It begins in immune cells located within the thyroid gland.
The results of a physical exam or laboratory test can reveal the presence of thyroid cancer. An examination of the neck may reveal a small or large mass in the thyroid. Lymph nodes may also be enlarged.
Lab tests and procedures used to diagnose thyroid cancer include:
• thyroid function tests
• a thyroglobulin test, which is used for papillary or follicular cancers
• an ultrasound of the thyroid
• a thyroid scan
• a thyroid biopsy
• calcium level in the blood
• phosphorous level in the blood
• calcitonin level in the blood
Treatment of thyroid cancer
Treatment will depend on what type of cancer you have and if it’s metastasized, or spread.
Most people undergo surgical removal of all or part of the thyroid gland. This removes your body’s ability to produce normal thyroid hormones. Oral supplements can replace thyroid hormones.
Other treatments include:
• radioactive iodine
• external beam radiation therapy
People diagnosed in the early stages of thyroid cancer generally respond well to treatment and go into remission. Some types of thyroid cancer have a higher rate of recurrence than others.
Make sure you go to routine follow-up appointments after you’re in remission. Doctors will need to check you for the rest of your life for signs of recurrent cancer. Your doctor will also want to routinely check that the amount of thyroid replacement hormones you’re taking is correct.
The cause of thyroid cancer isn’t determined in most cases. This means that for most people there’s no known way to prevent it.
It is known that medullary thyroid cancer is hereditary. Talk to your doctor if your family has a history of this type of thyroid cancer. Your doctor can refer you to a genetic counsellor who can determine how likely you are to develop thyroid cancer.
People who live near nuclear power plants are more likely to develop thyroid cancer than people who don’t. Talk to your doctor about potassium iodine pills if you live near a nuclear power plant.
Keep up with your annual check-ups, and let your doctor know if you’re having any new symptoms. This will make it more likely your doctor will find any serious health complications in the earliest stages.