A thyroid nodule is a lump found in or on the thyroid.
Nodules are found in roughly 6% of women and 1%2% of men.
In 95% of cases, thyroid nodules are found to be benign (noncancerous).
PORNCHAI SODA / Getty Images
PORNCHAI SODA / Getty Images
What Is the Thyroid Isthmus?
The thyroid is located at the front of the lower part of the neck.
These lobes are joined by a bridge of tissue known as the isthmus, which spans across the windpipe.
Verywell
The thyroid makes hormones that travel in the blood to tissues throughout the body.
Nodules in the lower portion of the lobes are believed to be at least risk for cancer.
Cancer risk from thyroid nodules is low.
Emily Roberts / Verywell
Malignant nodules occur in roughly 5% of all nodules.
The location where nodules are found is significant in determining cancer risk.
Thyroid cancer risk is highest for the isthmus, followed by the upper, then middle thyroid.
Risk Factors
There are a number of risk factors for thyroid cancer.
Some of theselike weightare modifiable risk factors, while otherslike agecannot be changed.
For men, diagnosis often occurs between the ages 60 and 70.
Thyroid cancer occurs more commonly in women than men.
The rate of thyroid cancer in women is about three times that of men.
The reasons for this are unknown.
The reason for this genetic link is currently unknown.
Radiation exposure can come from power plant accidents, fallout from nuclear weapons use, or some medical treatments.
Those who had radiation treatments involving the neck or head as children are at higher risk for thyroid cancer.
This risk typically increases the larger the dose or the younger the person at the time of treatment.
Radiation treatments for cancer in childhood also increase risk.
Thyroid cancer is common in those who have been exposed to radioactive fallout from power plant accidents.
However, given the slight risk, such tests should be avoided in children unless absolutely necessary.
Exposure to radiation as an adult poses less risk for thyroid cancer than in children.
Iodine in diet
A diet low in iodine is a risk factor for thyroid cancer.
However, a diet too high in iodine can also increase this risk.
Iodine deficiency is typically not an issue in the United States as iodine is added to table salt.
Any of the above symptoms could also be brought on by conditions other than thyroid cancer.
But if you have any of these symptoms, you should speak with your healthcare provider.
Sometimes those with nodules in the thyroid may see or feel a lump in their neck.
In rare cases, there may also be pain in the neck, ears, or jaw.
Emily Roberts / Verywell
Blood tests may be ordered to determine whether the thyroid is functioning normally.
It is done in patients whosethyroid-stimulating hormone(TSH) is suppressed below normal.
A thyroid scan should not be performed on women who are pregnant.
Ultrasound
Ultrasounds of the thyroid use high-frequency sound waves to get a picture of the thyroid gland.
A thyroid ultrasound is painless.
This procedure can be performed in a healthcare provider’s office, usually under ultrasound guidance.
These cells are then examined using a microscope.
Benign Nodules
Most cases of benign modules don’t require treatment.
Annual physical examination should also occur.
Medications like radioiodine may also be prescribed to treat “hot nodules.”
Depending on the nodules' characteristics, sometimes the entire thyroid is removed during surgery.
This procedure is called a total thyroidectomy.
Lymph nodes may also be surgically removed to get to determine cancer spread.
The therapies following surgery will be dependent on what is discovered during the surgical procedure.
In some cases, treatment will involve thyroid hormones and monitoring through blood tests and ultrasounds.
Using these therapies will cure or control the majority of cancers.
Less than 20% will recur.
Every year, approximately 2,180 deaths will occur from thyroid cancer.
This suggests the prognosis for men is worse than the prognosis for women.
Overall, the five-year survival rate for thyroid cancer is 98%.
But this varies based on the throw in and stage of thyroid cancer when discovered and its location.
If the cancer is localized to the thyroid only, the five-year survival is nearly 100%.
Roughly two-thirds of thyroid cancers are diagnosed at the localized stage.
A Word From Verywell
Nodules can grow in the thyroid for a variety of reasons.
Only a small percentage of nodules in the isthmus are found to be cancerous.
But cancerous nodules in this area are more likely to spread outside the thyroid.
Just because you have a nodule in the thyroid doesn’t mean you have cancer.
American Thyroid Association.Clinical thyroidology for the public:Volume 8 issue 2.
American Thyroid Association.Thyroid nodules.
2020 Mar;30(3):401-407. doi:10.1089/thy.2019.0478
Welker MJ, Orlov D.Thyroid nodules.Am Fam Physician.
2003 Feb 1;67(3):559-66.
American Cancer Society.Thyroid cancer risk factors.
American Cancer Society.Signs and symptoms of thyroid cancer.
American Cancer Society.Key statistics for thyroid cancer.
