Thyroid Nodules and Thyroid Cancer
A thyroid nodule is a bump or lump in the thyroid itself, and most of the time it is benign. This page explains how it is found, what ultrasound and needle biopsy do, how follow-up works, what the warning signs are, and that the decision about follow-up is up to the doctor.
What is a nodule?
A thyroid nodule is a small bump or lump found within the thyroid gland itself. The Endocrine Society says nodules are very common and become more common with age. Most of them are benign. The American Cancer Society explains that many nodules are fluid-filled cysts, and even most solid nodules are not cancer.
The Endocrine Society says about 8 percent of nodules in men and 4 percent in women are cancerous. In other words, most are not. This number is approximate, and for your nodule it is the doctor who tells you, based on ultrasound and biopsy.
Nodules usually do not disturb thyroid function, and hormone levels stay normal. A small number are “active nodules” and make too much hormone. The NHS and NIDDK list these nodules as one cause of an overactive thyroid.
Symptoms
Most nodules cause no symptoms and are found during an exam or imaging of the neck. If there are symptoms, the NHS lists these for thyroid cancer:
- A firm, painless lump low at the front of the neck that slowly grows
- A hoarse voice
- Difficulty swallowing or breathing
- Pain or pressure at the front of the neck
The NHS stresses that these symptoms are common and have many causes. So they are not a diagnosis of cancer by themselves. But because early diagnosis makes treatment easier, they should be checked.
Who should be seen?
Make an appointment if:
- You feel or see a lump at the front of your neck.
- Your voice is hoarse or swallowing has become hard and it does not get better.
- You have pain or pressure at the front of the neck.
- Your ultrasound or CT report says “nodule” and you do not know what to do.
The NHS says that if you are having difficulty breathing, you should get an urgent appointment. If the shortness of breath is severe or getting worse, do not wait for an appointment: go to the emergency room.
How is it evaluated?
The Endocrine Society lists these steps:
- Blood test to measure how the thyroid is working. This test does not find cancer.
- Ultrasound: shows whether the nodule is solid or cystic, its size and location, and whether it has suspicious features. Based on this, the doctor suggests one of these: a biopsy, a repeat ultrasound, other imaging, or no further action.
- Fine-needle biopsy (FNA) under ultrasound guidance. It is usually recommended for a nodule larger than 1 cm or with a concerning feature.
- Radioactive iodine scan: a small amount of radioactive iodine shows whether the nodule is active. It is usually done when the blood test shows an overactive thyroid.
The NHS says the biopsy result usually takes about two weeks, sometimes longer, and a delay does not necessarily mean a problem. If cancer is confirmed, more tests such as CT, MRI or PET are needed to determine the spread.
This is a general explanation. Ultrasound and biopsy are done at an equipped center, and this page does not say where or by whom.
What do treatment and follow-up look like in general?
The Endocrine Society says:
- Benign nodule: Most of the time it is monitored without surgery, with repeat ultrasound. The ultrasound interval depends on the size and features of the nodule. If the nodule grows, a repeat biopsy may be needed.
- Large nodule that makes swallowing or breathing hard: Surgery may be needed.
- Active nodule: It is rarely cancerous and is treated with surgery or radioactive iodine.
- Cyst that causes discomfort: Draining, surgery or minimally invasive ablation is possible.
- If the biopsy shows cancer or is suspicious: Removal of the thyroid is usually recommended, and sometimes radioactive iodine afterward to destroy remaining tissue.
The American Cancer Society lists the types of thyroid cancer: papillary about eight in ten cases, follicular about one in ten, and less common types. Papillary is usually slow-growing, and it calls it “rarely fatal.” The type and treatment plan are set by the care team.
What can you do?
- Keep the ultrasound report and the biopsy result with their dates and bring them to your appointment. If you have images or a disc, bring them too.
- Do not stop follow-up on your own and do not change its interval yourself. The doctor sets the interval based on the size and features of the nodule.
- Note any change in voice, difficulty swallowing, or the size of the lump, and mention it at the next visit.
- If you have a nodule and are pregnant or planning pregnancy, tell the doctor.
When to get urgent help
If breathing has become hard or swallowing suddenly got worse, do not wait for a routine appointment. The NHS gives an urgent appointment for difficulty breathing. If the shortness of breath is severe or getting worse, in Iran call 115 (Iran’s emergency number, not valid abroad). See the full list in the guide “When should I call right away?”.
Frequently asked questions
Does a nodule mean cancer?
No. The Endocrine Society says thyroid nodules are very common, become more common with age, and most of them are benign. The American Cancer Society also says most nodules are not cancer, even solid nodules, which carry more risk than cysts. Judging your nodule is a matter for ultrasound and the doctor's opinion.
Can a blood test show whether a nodule is cancer?
No. The Endocrine Society says a blood test measures how the thyroid is working but does not find cancer. Ultrasound shows the features of the nodule, and based on that the doctor decides whether a biopsy, a repeat ultrasound or something else is needed.
What is a needle biopsy (FNA) and does it hurt?
The Endocrine Society says that in this method, cells or fluid are taken from the nodule with a thin needle under ultrasound guidance. It is usually recommended for a nodule larger than 1 cm or one that looks concerning, and most patients tolerate it well. The NHS says the result usually takes about two weeks. This is only a general explanation, and the doctor decides where it is done.
If my nodule is benign, do I still need follow-up?
The Endocrine Society says nodules that are not operated on are usually monitored with repeat ultrasound, and the interval depends on the size and features of the nodule. If the nodule grows, a repeat biopsy may be needed. The doctor decides the interval and type of follow-up.
What symptoms does a nodule cause?
Most nodules cause no symptoms and are found during an exam or by chance on imaging. For thyroid cancer, the NHS lists these: a firm, painless lump low at the front of the neck that slowly grows, a hoarse voice, difficulty swallowing or breathing, and pain or pressure at the front of the neck. These symptoms have other causes too and are not a diagnosis.
What happens if it is cancer?
The American Cancer Society says the most common type is papillary, about 8 in 10 cases, usually slow-growing and rarely fatal. The Endocrine Society says that if a biopsy shows cancer cells or is suspicious, removal of the thyroid is usually recommended, and sometimes radioactive iodine afterward. The type and plan are set by the care team.