In this episode of PodMD, Specialist Endocrine Surgeon and Surgical Oncologist Associate Professor Anthony Glover will be discussing the topic of Thyroid Nodules. We discuss their symptoms, the detection of thyroid nodules with modern imaging, ultrasound guided FNA biopsies, and more.
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Today I’d like to welcome back to the PodMD studio Associate Professor Anthony Glover.
Anthony is a Specialist Endocrine Surgeon and Surgical Oncologist who specialises in the work-up and treatment of diseases and tumours of the thyroid, parathyroid and adrenal glands.
You can read more about Anthony on his profile page on our PodMD website.
*Please listen to our disclosure at the end of this podcast
Today, we’ll be discussing the topic of thyroid nodules. Anthony, thanks very much again for talking with us on PodMD today.
Anthony: Thank you for having me.
To start at the beginning, what exactly is a thyroid nodule and how would you explain it to a patient?
Anthony: Yeah, so a thyroid nodule is an overgrowth of cells within the thyroid. With patients, usually around 90% of thyroid nodules are benign. So they’re not due to any cancer. And they’re very common in Australia. And the reason they often form is that sometime during a person’s life, they haven’t had enough iodine in their diet. And so the thyroid becomes more active and some cells in the thyroid start dividing to try and take more iodine from the person’s blood to make thyroid hormone. And so that can form a thyroid nodule. And with benign thyroid nodules, often they slowly grow with time and they can cause symptoms of pressure or other symptoms in the neck. And for about 10%, so one in 10 thyroid nodules, it may be due to a thyroid cancer, which will usually have a different treatment.
How do thyroid nodules typically present in general practice? Are they usually symptomatic or picked up incidentally?
Anthony: Yeah, recently definitely thyroid nodules are found more commonly incidentally, so it’ll be very common presentation where someone will present with some other unrelated symptoms such as a cough or maybe a feeling of pressure in their neck or some other symptoms in their neck and they have an ultrasound of their neck and thyroid nodules are found incidentally. So that’s probably the most common presentation. So it would be more than half to probably two-thirds of patients who are diagnosed with a thyroid nodule. A smaller number of people can present with symptoms. So usually that will be as if the thyroid nodules grow or if they’re in a certain location in the thyroid. And the most common symptoms would be a feeling of increasing pressure in the neck, discomfort swallowing, or occasionally difficulty breathing if the thyroid nodules are pushing on the trachea. Occasionally, as well, people can present with a change in their voice, which can be due to the thyroid nodules putting pressure on the recurrent laryngeal nerve, which applies the vocal cords and which is located with the thyroid in the neck.
Are there particular symptoms that should make a GP more concerned about an underlying malignancy?
Anthony: So as for thyroid cancers, as they get larger, they can invade into the surrounding structures. So the particular symptoms we most worry about is a change in voice, especially a hoarseness in the voice, which could indicate if a thyroid nodule was a cancer, that it’s either putting pressure or invading into the recurrent laryngeal nerve. Other symptoms may be if a person presents with a high thyroid nodule and also a palpable lymph node in the neck, that could be due to a thyroid cancer. But often, especially with smaller thyroid cancers, they’re diagnosed similarly to thyroid nodules, so just incidentally found on other imaging. But yeah, if there’s any symptoms such as change in the voice new lymphadenopathy of the lymph nodes in the neck or a firm hard thyroid nodule, they all could be signs that a patient has a thyroid cancer.
And how common are thyroid nodules and has their detection changed with modern imaging?
Anthony: Thyroid nodules are very common and they’re more diagnosed, like diagnosed more commonly as people aged. So about for people around the age of 70, it’s estimated that around half to 3/4 of people will have a thyroid nodule if they have an ultrasound of their thyroid. And they become more common with age and they’re generally rare in younger people, and especially in people under 20. But yeah, they do become more common with age.
When a GP first encounters a thyroid nodule, what are the key things they should focus on in the history?When a GP first encounters a thyroid nodule, what are the key things they should focus on in the history?
Anthony: Yeah, so definitely the first thing is understanding what the patient’s thyroid hormone status is. So could they have overactive thyroid or underactive thyroid, so hyperthyroidism or hypothyroidism? So asking if they have any symptoms around that with regards to energy levels. on how they sleep, any change in weight. The other things to consider with thyroid nodule is their family history. So does the person have a family history of thyroid cancer or have they had any past exposure to radiation treatment? So both of those are risk factors for thyroid cancer and so they may change how the thyroid nodule is worked up.
On examination, which features are most helpful in risk-stratifying a thyroid nodule? Are there any examination findings that would prompt an urgent referral?
Anthony: Yeah, so I think definitely feeling the size of the nodule and how it feels. Generally, if the nodule is larger than a centimetre, it can be felt within the neck. The examination findings that would mean that someone needs Urgent referral would be signs of increasing pressure in the neck, so especially if they’re getting any airway changes such as having like stridol, then they should have an emergency referral. Or any signs of that the thyroid nodule could be a thyroid cancer, so a permanent change in their waist, classically hoarseness, or having associated lymphadenopathy with the thyroid nodule.
In a typical primary care setting, what does a sensible initial workup look like for a thyroid nodule?
Anthony: Yeah, so for the initial testing, the thyroid function should be checked. Most thyroid nodules are not functional, so the thyroid function with a TSH will be normal, but a small number of thyroid nodules may produce thyroid hormones so you can get an autonomous thyroid nodule so it can sometimes cause thyroid toxicosis or subclinical thyroid toxicosis. And the main reason to do the thyroid function initially is that will help with the additional imaging. If you detect the thyroid nodule and the patient wants to investigate it further besides doing thyroid function, or they have any symptoms or the nodule is bigger than a centimeter, then the usual initial test will be a thyroid ultrasound and also ultrasound of the neck, which will look at the nodule and the size of it, its ultrasound features, and if there are any other nodules or enlarged lymph nodes in the neck. If the patient does have a low TSH suggesting hyperthyroidism, then a nuclear medicine scan can also be useful to understand if it is the thyroid nodule making too much thyroid hormone or if they have another problem with their thyroid that is causing that.
Where does thyroid function testing fit into the picture and how does it guide next steps?
Anthony: So it’s pretty much the initial test to do. And so it helps understand if the thyroid nodule could be functional or not and help decide if the patient should have a thyroid nucleus scan or not. Most thyroid nodules aren’t functional, so aren’t producing too much hormone. But if they are, then that can give more information about if that nodule is responsible, which can help guide treatment.
An ultrasound plays a central role. What are the key features GPs should look out for in an ultrasound report?
Anthony: Yeah, so with the ultrasound, the ultrasound will report the size of the thyroid nodule. So generally if a thyroid nodule is larger than 4 centimeters, generally the patient would be recommended to go to consider surgery as even if that nodule is shown to be benign. By biopsy, there can still be around a 10% risk of it being a thyroid cancer. The other features that the ultrasound will show is how likely or the risk that this nodule could be a thyroid cancer. So there’s a number of different scoring systems which are used, but what they do is they look at how the thyroid nodule appears compared to the rest of the thyroid, the size of it, if it has any irregular edges and if it has changes within the nodules, such as changes of microcalcification, which can be associated with cancer. And usually with the ultrasound report, the radiologist will give you a recommendation about whether this thyroid nodule should be biopsied or not.
We often see TIRADS scores included. How should these be used in a practical decision-making way?
Anthony: Yeah, so the Thyroid Score is a system that was developed in the United States by the College of Radiology there. And it’s very widely used. So it’s probably the most widely used scoring system for thyroid nodules on ultrasound in Australia. It’s a very useful system as it will give a guide about when to biopsy a thyroid nodule. And it looks at those features I was talking about before and gives them a score and gives a risk about whether a nodule may be a cancer or is unlikely to be a cancer. And depending on that risk, it gives an indication about when a nodule should be biopsied. So it can be a very helpful way to understand all the different features on a thyroid nodule and what the next step should be. Sometimes the Thyroid score may recommend that the nodule be observed which usually would involve having another ultrasound in one or two years to see any changes in the nodule. And sometimes with a TIRADS score, it may recommend that the nodule doesn’t need any further observation or treatment. So it is quite a useful score that’s generally included in most ultrasound reports in Australia.
At what point should a GP consider arranging or referring for an FNA biopsy?
Anthony: Yeah, so the most common reason would be if it, with the Thyroid score or the ultrasound report suggests the thyroid nodule could be a thyroid cancer, then the patient should be referred for having an ultrasound guided FNA biopsy. Other reasons would be if a patient has a thyroid nodule and has those risk factors, associated with thyroid cancer, so having a family history of thyroid cancer or having prior radiation. For patients that are diagnosed with thyroid nodules when they’re young, so especially people under 20, they should be considered for a biopsy or for patients that have nodules and symptoms, so especially if they have a large a thyroid with multiple nodules in a large goiter and are getting pressure symptoms, then that’s worthwhile considering whether the nodules should be biopsied. Or it may be worthwhile just to refer a patient to an endocrine surgeon or another specialist with experience in the thyroid to decide what to do further.
When biopsy results come back, particularly indeterminate ones, how should GPs interpret and act on them?
Anthony: Yeah, so with the biopsies, generally the result of the biopsy were reported under one of six categories. So that’s the Bethesda system of thyroid nodule cytology. The most common result will be that the nodule is benign on biopsy. So generally those patients, if they’re asymptomatic, they won’t need any immediate management. But generally they should have another ultrasound in one or two years to check if there’s any change in the nodule. If the results of the biopsy suggest that the nodule is a thyroid cancer, then they should be referred to a specialist to discuss further treatment. And in between those two results, there is the atypical or indeterminate results, which come back as Bethesda 3 or 4. And so there is a number of different treatment options patients can consider, which can range from repeat biopsy, diagnostic surgery for their to remove that side of the thyroid to get a diagnosis of the thyroid nodule, or molecular testing, which is a new way of assessing thyroid biopsies, which can also be helpful for patients with those diagnoses.
When should a GP refer a patient with a thyroid nodule to a surgeon or a specialist? Are there cases where referral is commonly delayed when it should happen sooner?
Anthony: So I think any patients who have a symptomatic nodule or if they have a biopsy suggesting it is a thyroid cancer or atypical indeterminate nodule generally should be seen by a specialist. Generally, most patients don’t have much delay. Occasionally for patients that have multiple nodules in their thyroid, and if their thyroid is slowly growing, don’t want to see a specialist, and it can be hard to know when they should be referred. So generally I would look at their progress ultrasounds, and if the thyroid nodules are growing slowly, say, one or one centimeter every year or so, but the thyroid volume is increasing. We know that as those nodules are probably going to continue to grow and the thyroid volume will increase. And once the thyroid volume reaches a size of more than 40 or 50 mils on one side, it’s likely the patient will get symptoms. So that can be a reason to refer them and especially can help people decide if they wish to have treatment for their thyroid nodules.
And for nodules that don’t need immediate intervention, what does appropriate monitoring in general practice look like?
Anthony: So generally that will be having a progress ultrasound scan in one or two years and the TIRAD score will usually give a recommendation for that. Some nodules may not need any further monitoring, especially if they’re very small or if they have a very low risk of being a thyroid cancer. And generally for those patients, if they aren’t having any further imaging, I just counsel them that we know that they have a thyroid nodule It’s very low risk. It probably won’t change in the future, but there is a small chance it may grow or change with time. And if they notice any changes in their neck, like feeling the nodule or feel that it’s changed or any symptoms of pressure or difficulty swallowing, then they should have an additional ultrasound and come back for review.
Perfect. And what are some common pitfalls you see in primary care when managing thyroid nodules?
Anthony: So I think thyroid nodules are very common, so it’s hard to know when to intervene and often they’re found on imaging that’s being performed for another reason. So I think there is a lot of nuance in their management, but I think just reassuring patients that most nodules are benign and using that TIRAD score to reassure patients and try and avoid patients having biopsies unless they’re recommended to, or if they have symptoms, or if there’s some other risk factor. Because we do know that many patients that do have a thyroid nodule will end up having overdiagnosis of small thyroid cancers. So these kind of systems such as the Thyroid scores and other management try to avoid overdiagnosing patients with small thyroid cancers that won’t grow. So I think just following those advice, but then also if they’re unsure or the patient has any symptoms, it’s worthwhile having a specialist who has experience with managing a lot of patients with thyroid nodules to assess the patient and also discuss all the nuances in the management.
To sum up for us, could you please identify the three key take-home messages from today’s podcast?
Anthony: For sure, yeah. So thyroid nodules are very commonly diagnosed in clinical practice. The initial assessment involves assessing the thyroid function and understanding if the patients have any symptoms from the thyroid nodules. And further testing is done with ultrasound and to use the TIRAD score from the diagnostic ultrasound to decide if a biopsy should be performed or if this nodule should be monitored.
This has been great, Anthony. Thanks again for the time and insights you’ve provided today.
Anthony: Thank you.
*We do hope you enjoy this podcast but please remember that the advice here is of a general nature and is not intended as specific advice about a given patient. The views and opinions expressed in this podcast are those of the doctor, not PodMD. If you do have a patient on whom you require specific advice then please seek advice from a colleague with appropriate expertise in that area.
