In this episode of PodMD, Head and Neck Surgeon, Surgical Oncologist and General Surgeon Dr Jingyi Cao will be discussing the topic of thyroid nodules. We discuss how GPs should start the evaluation of thyroid nodules, TIRADS, interpretation of Bethesda categories, clear referral triggers, 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 Jingyi Cao.
Dr Jing is a head and neck surgeon, surgical oncologist, and general surgeon specialised in treating thyroid, parathyroid, and salivary gland diseases, as well as soft tissue tumours and advanced skin cancers.
Graduating from the University of Melbourne School of Medicine in 2010, Jing went on to obtain her fellowship in general surgery with the Royal Australasian College of Surgeons in 2019. She further specialised in head and neck surgery and surgical oncology at Westmead Hospital and the Crown Princess Mary Cancer Centre, Westmead.
Jing was also awarded a Master of Philosophy in Medicine from the University of Sydney in recognition of her clinical research and thesis on the surgical management of secondary and tertiary hyperparathyroidism.
*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.
The topic of today’s discussion is thyroid nodules. Many GPs ask, when should I order a biopsy? How do I interpret the cytology report? And when should I refer to a head and neck surgeon? So Jing, to start us off, can you explain how should GPs start the evaluation?
Jing: No problem. The first step is always a good history and exam. Ask about risk factors like radiation exposure, family history – especially of thyroid cancers, or any compressive symptoms or rapid growth or other red flag symptoms. Then, it would be useful to organise for thyroid ultrasound. The ultrasound is crucial because we apply the TIRADS scoring system to then decide whether or not a biopsy is needed.
Question 1
Alright, and can you explain TIRADS in simple terms?Jing: Absolutely. TIRADS stands for Thyroid Imaging Reporting and Data System, developed by the American College of Radiology. It scores nodules based on ultrasound features, including features such as the composition of the nodule, echogenicity, shape, margin, and echogenic foci. Each feature scores points, and the sum places the nodule into categories from TIRADS 1 to TIRADS 5.
Now, TIRADS 1 to 2 usually suggest benign nodules or nodules that are not suspicious of malignancy. For those ones, no biopsy is needed, just routine follow-up.
TIRADS 3 is mildly suspicious, and therefore, biopsy is recommended if the diameter of the nodule is greater than or equal to 2.5 centimeters. Otherwise, surveillance is adequate.
TIRADS 4 suggests moderately suspicious nodules, so biopsy is recommended if the diameter of the nodule is greater than or equal to 1.5 centimeters. Otherwise, monitor or surveillance.
TIRADS 5 is highly suspicious and therefore will require a biopsy, especially if greater than or equal to 1 centimetre. This helps, so this TIRADS scoring system helps avoid unnecessary biopsies of benign nodules. Some alternative risk stratification systems and guidelines for biopsy versus surveillance based on ultrasound findings include ATA guidelines and the EU TIRADS. However, these are more pattern-based rather than an actual scoring system, and can be a little bit harder to follow in a general practice setting. So the American College of Radiology TIRADS is a very useful system to follow.
Question 2
All right, that’s so interesting. So once we biopsy, we often see Bethesda categories in the cytology report. How do we interpret this?Jing: So the Bethesda system standardizes FNA results into six categories, each with a risk of malignancy associated, and a recommended next step. So, Bethesda 1 suggests non-diagnostic result and usually it’s because of an insufficient amount of cells or samples that’s obtained. The risk of a malignancy associated with that is 1 to 4%, and a repeat FNA is recommended. We usually suggest repeat FNAs in about 3 months time from the initial FNA just to minimize the reactive or inflammatory effect from the initial FNA.
Bethesda 2 suggests a benign lesion. The risk of malignancy associated with that is 0 to 3%, and usually surveillance of ultrasound is recommended for these lesions. Note that the risk of malignancy; there’s a range of up to 3%, and that’s because, as with any biopsies or FNAs, there’s always that possibility of sampling error, even if the result comes back as benign.
Bethesda 3 means atypia. or follicular lesion of undetermined significance. The risk of malignancy associated with this is about 5 to 15%. So for these ones, usually a repeat FNA in a few months’ time is recommended. And certainly consider referral to a head and neck surgeon if the FNA result remains the same. Or in some cases, an early referral to a surgeon for organisation of a repeat FNA is very appropriate as well.
Bethesda 4 correlates to follicular neoplasm or suspicious for follicular neoplasm. The risk of malignancy with Bethesda 4 is about 15 to 30%. And the recommendation is certainly referral to a surgeon for management of these ones because cytology alone from the FNA actually cannot distinguish between a follicular adenoma, which is benign, versus a follicular carcinoma, which would be malignant.
Bethesda 5 correlates to nodules that are suspicious for malignancy. So the risk of malignancy associated with these ones are actually 60 to 75%, and surgical referral is recommended. And Bethesda 6, means basically malignant lesions. So the risk of malignancy for these ones are 97 to 99%, and surgical referral for management is also recommended.
Question 3
Alright, and Jing, for benign nodules, when should we keep watching and when do we stop?Jing: Now, if a nodule is benign and not causing symptoms, it’s very appropriate to follow up with repeat ultrasound at 12 to 14 months. If the size of the nodule is stable, then one can extend the surveillance period to 2 to 3 yearly, even. If it grows significantly, therefore more than 20% as a guide in 2 dimensions, or more than a 2 millimetre increase in the solid component, then consider repeat FNA, or refer to a surgeon.
Question 4
And what are the clear referral triggers for GPs, Jing?Jing: I think it would be important and appropriate to refer to a head and neck surgeon if you get a Bethesda 4 or 5 biopsy result. If there are red flag symptoms, such as a nodule being rapidly enlarging, or if the patient is very symptomatic from it or developing any compressive symptoms from the nodules.
If there are suspicious ultrasound features, especially in a high-risk patient, such as those that have had previous thyroid cancer, family history of thyroid cancer, or neck radiation previously, even if the FNA is benign.
For patients with recurrent cystic nodules causing symptoms, and also any large nodules greater than 4 centimetre, even if benign on biopsy, it would be quite adequate to consider referral for review and discussion with a surgeon.
Question 5
Right, Jing, are there cases where the GPs don’t need to refer?Jing: Yes, most benign small nodules can be followed in general practice, for sure, with surveillance imaging. If there is uncertainty, it’s always a good idea to discuss directly with a head and neck surgeon before formal referral.
Question 6
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 nodules?Jing: No problem. I think, firstly, use TIRADS to decide who needs a biopsy, then Bethesda to guide management, and often it’s useful to have a bit of a flowchart to guide those decision-makings. Secondly, most nodules are benign and need only monitoring, so reserve referral for suspicious or symptomatic cases. Thirdly, clear communication between the GP, radiologist, and surgeon makes the pathway smooth for these patients.
Thanks again for your time and the insights you’ve provided, Jing.
Jing: My pleasure. Thank you.
