In this episode of PodMD, Specialist Endocrine and General Surgeon Dr Nicole Rodrigues will be discussing the topic of thyroid nodule work up. We discuss the importance of having a structured approach to evaluating thyroid nodules, key elements of history and physical exam that guide work up, how FNA results are classified, and more.
- Transcript
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*As always, all in this PodMD podcast is intended for health professionals and the comments are of a general nature. Information given is not intended as specific medical advice pertaining to any given patient. If you have a clinical issue with one of your patients please seek appropriate advice from a colleague with expertise in the area.
Today I’d like to welcome to the PodMD studio Dr Nicole Rodrigues.
Dr Rodrigues is a specialist Endocrine and General Surgeon practicing in Canberra. After spending 11 years in the city completing her medical degree at the Australian National University and General Surgery training through the Canberra training network, she went on to pursue advanced subspecialty training in Endocrine Surgery.
She completed the prestigious ANZES Endocrine Surgery Fellowship at two of Australia’s leading centres — St George Hospital in Sydney and The Alfred Hospital in Melbourne.
Dr Rodrigues has a special interest in the surgical management of thyroid, parathyroid, and adrenal disorders, including thyroid cancer, Grave’s disease, hyperparathyroidism, and adrenal lesions, both functional and non-functional.Alongside her endocrine practice, she also performs a broad range of general surgical procedures such as laparoscopic hernia repairs, laparoscopic cholecystectomy and skin cancer excisions.
*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.
Today, we’ll be discussing the topic of work up of thyroid nodules. Nicole, thanks for talking with us again on PodMD today.
Nicole: Thank you for having me.
The topic of today’s discussion is the work up of thyroid nodules. Nicole, why is it important to have a structured approach to evaluating thyroid nodules?
Nicole: Thanks for that. So thyroid nodules are very common and they present on up to 67% of ultrasounds. Only about 5% of these are palpable, and so the vast majority will be detected incidentally on other imaging that’s performed in the region. So they tend to be more sort of incidental findings and the incidence of these being detected is increasing as people are having more imaging, tests performed.
The risks of a thyroid nodule being malignant is about 15% overall. So I think it’s important to have a structured approach to distinguishing the benign from the malignant nodule, as we want to avoid overtreating the benign nodules, but also ensure that the malignancies are being properly picked up and managed.
So what are the key elements of history and physical exam that guide the workup?
Nicole: So the main indications that we would do surgery for thyroid are local compression, hyperthyroidism and malignancy. So history and exam would be mainly looking for these symptoms. In the history we look for rapid growth, compression symptoms such as pressure, difficulty swallowing or breathing, particularly when lying on their back on their sides, as well as any voice changes.
Symptoms of hyperthyroidism such as palpitations, heat intolerance, tremors and anxiety, could prompt you to think of doing sort of further thyroid function testing, and any sort of risk factors for thyroid pathology, certainly exposure to ionising radiation, especially in childhood, is a known risk factor for thyroid cancer, as well as knowing about any family history of thyroid cancer or other thyroid pathologies also useful.
In the examination, particularly looking for any hard or fixed nodules, as well as any cervical lymphadenopathy that might raise suspicion for a malignant nodule.
Nicole, why is TSH the first lab test ordered and how does it influence next steps in the work up?
Nicole: So the TSH will tell us if there’s thyroid toxicity, either due to hot nodule or toxic multi nodular equator. So if a low TSH is found on the blood tests, a nuclear medicine scan should be performed and that can assess the pattern of over activity to help guide subsequent management. So the single hot nodule, then potentially surgery could target just that side, or if it’s a diffuse pattern or a toxic multinodular goitre with multiple hot nodules, then that will influence the extent of surgery.
Which imaging modality is most useful for thyroid nodules and what specific features are assessed during the thyroid ultrasound that help determine if a nodule is suspicious?
Nicole: So ultrasound of the thyroid is the most useful modality for looking at nodules. It has sensitivity of about 95% for detecting nodules, even as small as one to three millimetres. Based on the ultrasound findings and characteristics of the nodules, we use the ACR-TIRADS classification to stratify these thyroid nodules and they’re scored based on various characteristics into TIRADS one to five. The main sort of features that indicate a suspicious nodule would be a solid nodule that’s very hypoechoic with irregular margins that are taller than wide and microcalcifications certainly the most sensitive finding to indicate a malignancy. And the decision to then proceed to a FNA biopsy depends on the sonographic pattern and the size of the nodule. So in a TIRADS 3 nodule that’s more than 2.5 centimetres, a TIRADS 4 that’s more than 1.5 centimetres, or a TIRADS 5 that’s more than one centimetre, those would be the nodules that proceed to an FNA biopsy.
I see. How are FNA results classified?
Nicole: So once an FNA is performed, the cytology is then classified using the Bethesda classification for thyroid nodules and this plays a key part in determining what the most appropriate management and follow up of thyroid nodules are.
So the Bethesda classification classifies cytology from 1-6, with 1 being non diagnostic, 2 being benign, 3 being indeterminate, 4 being a follicular neoplasm, 5 suspicious for malignancy and six being malignant.
What are the implications of the various Bethesda categories?
Nicole: So it’s important that we know what the Bethesda categories is of cytology of thyroid nodule as the risk of malignancy increases in each category. The majority of nodules will be benign or Bethesda true, and they can be monitored with repeat ultrasound for any changes over time, usually in sort of 12 or 24 months. All other results should generally be referred to an endocrinologist or a thyroid surgeon like myself for further assessment.
As management of indeterminate cytology can be quite complex due to the uncertainty and malignancy risks in these categories such as the three and the four can be up to 30%, so not insignificant. Still the majority will be benign at the end, but because of that diagnostic uncertainty, it’s always better to have a specialist opinion to be able to guide the patient in the subsequent management decisions. We can help with interpreting the ultrasounds and the FNA results to see what would be the best management option tailored to that specific patient.
And certainly any malignancy or suspected malignancy, so Bethesda 5 and 6 should be referred directly to a thyroid surgeon for discussion about surgery.
So how do clinicians decide between monitoring, further testing or surgical referral after the initial work up?
Nicole: So certainly the Bethesda classification plays a big role in that decision making process. I would use that cytology finding as well as correlating with the ultrasound appearance to determine whether these results are concordant. And also taking into account any patient’s symptoms of local compression to decide whether this is a nodule that needs any surgical intervention.
Sometimes also depends on a discussion with the patient as to their risk tolerance as to whether they want to monitor a nodule long term, or whether they would like definitive management. So based on all of these factors, I can then recommend whether the patient should be followed up with repeat ultrasounds or if they should have a repeat for FNA, or if they proceed to surgery for either a diagnostic procedure or a therapeutic procedure.
What role does the GP play in assessment and management of thyroid nodules?
Nicole: So GPs play a central role in this process, so the primary goal for yourself is to differentiate between a benign and a malignant nodule. And so the key step is sort of early recognition and work up of any detected thyroid nodules on any imaging modality to then proceed to doing an ultrasound to define those TIRADS sort of characteristics and then based on that appropriately referring patients to have an FNA for more detailed analysis of that cytology, to then being able to decide on their management pathway depending on the Bethesda criteria that’s returned in the initial work up.
Also determining thyroid activity using a TSH to then decide if they are needing to have a nuclear medicine scan and then referring to an endocrine surgeon like myself for any further sort of discussion for the indeterminate biopsies or any cancers for discussion about management.
Thank you for your time here today in the PodMD studio. To sum up for us, could you please identify the three key take home messages from today’s podcast on thyroid nodule work ups?
Nicole: Thank you for having me. I’d say the three take home messages are that thyroid nodules are very common and you’re very likely come across a patient with one due to the increasing use of imaging for various reasons. Early sort of work up with a TSH and ultrasound and FNA are the key investigation modalities.
Then early referral of any sort of non diagnostic or indeterminate nodules for discussion about management options also useful.
Then certainly the clearly benign or clearly malignant nodules have a bit more of a defined treatment pathway, but I find that there’s certainly those non diagnostic or indeterminate nodules that are in a bit of a grey zone that people have a bit of uncertainty with and that’s certainly where we’re here to help you with deciphering that.
Thanks Nicole. Thanks again for your time and the insights you’ve provided.
Nicole: Thank you very much.
