The thyroid gland is one gland located at the base of the neck. It produces thyroid hormones, which control how the body uses energy.
A thyroid nodule is a solid or fluid-filled lump in the thyroid gland. Most thyroid nodules are small, cannot be felt, and cause no symptoms. They are caused by an overgrowth of cells in the thyroid gland. In a few people, the nodules grow and cause symptoms such as pressure, difficulty swallowing, or breathing.
Thyroid nodules are very common, with more than half of the people scanned show small nodules.
So they can never cause problems and are only discovered incidentally. But when should you follow up and treat?
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Who gets them
Nodules are more common discovered in women, three times as fast as in men. The incidence too increases with age.
By age 30, it is estimated that about 30% of women will have a lump. By age 70, about 70% of women will have at least one. The risk of a thyroid nodule is also higher if you have other thyroid conditions, such as Hashimoto’s disease, or have been exposed to radiation. However, alone a very small share of the adult population will require treatment or investigation for nodules.
People often find out they have thyroid nodules during a routine checkup or when investigating some other unrelated health problem. Thyroid nodules are easily seen on common imaging tests such as an ultrasound or CT scan. As access to and use of clinical imaging is growing rapidly, and as we get to the doctor more and more as we age, the chance of incidentally finding thyroid nodules has increased.
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When should you be concerned?
It’s understandable that people worry that a thyroid nodule could mean cancer. But we know now around 10% of patients with thyroid nodules harbor cancer – so about 90% of detected nodules pose no cancer risk.
In general, the risk is only increased if you have a past exposure to radiation, a family history of thyroid cancer, obesity, or if you are under 20 years old at the time of discovery of the nodule. Troubling symptoms include: enlarging thyroid nodule, recent onset of hoarseness, difficulty swallowing, neck pain or discomfort, large firm nodule, or surrounding enlarged lymph nodes.
Your medical history and any physical symptoms related to the thyroid should always be discussed with a doctor. They can recommend further research or monitor changes over time. The idea of observing may sound counterintuitive, but it can be important because further investigation is not always in your best interest.
Treatment for thyroid nodules depends on whether the nodule is suspected to be cancerous or is causing symptoms such as neck pain or an overproduction of thyroid hormones. Often no formal treatment is required for thyroid nodules.
Read more: 29,000 cancers overdiagnosed in Australia in one year
When detection leads to poorer health
There is an important problem with ‘accidentally’ found thyroid nodules.
In recent decades, the dramatic increase in new cases of thyroid cancer has been largely driven by findings of small, low-risk thyroid cancers; found when examining thyroid nodules. There is strong evidence that overdiagnosis – that is, a correct but unnecessary diagnosis – is responsible for a big contribution of thyroid cancer cases.
We know that despite a rapid increase in thyroid cancer diagnoses, the number of people who die from it (the death rate) has remained stable. This means that most of these cancers are found unnecessary. And finding it can be worrying and sometimes lead to treatments and financial costs that may not have been necessary at all in the end.
Overdiagnosis and beyond overtreatment of this condition has been extensively documented. But figuring out how to avoid and deal with these problems remains difficult. The American Thyroid Association is a leading treatment group for the treatment of thyroid nodules. It recommends nodules smaller than 1 centimeter should not be routinely biopsied. In line with this, ultrasound systems have been introduced to reduce patient overtreatment small thyroid nodules.
In 2020, we performed community research and found that Australians were unaware of the harms of overdiagnosing low-risk thyroid cancer. They wanted more community education and supported the idea of clinical guidelines to minimize over-research and over-treatment of low-risk conditions.
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Read more: Low- and middle-income countries struggle to provide health care to some while over-medicating others
Advice for home
While there is a small proportion of thyroid nodules that cause damage, the vast majority are found incidentally and are not likely to cause further problems.
Investigating and treating these nodules can lead to unwarranted physical, psychological, and financial consequences, including overdiagnosis, overtreatment, anxiety, and out-of-pocket costs.
It’s important to be aware of the issues involved in finding a thyroid nodule, and to ask questions – for ourselves and our loved ones – about what this means and whether further testing or treatment is really necessary.
