Happy 2024 and welcome to another blog post!
Today's topic is thyroid nodules and how to deal with them.
Q: How common are thyroid nodules?
Nodular disease of the thyroid gland is quite prevalent in the Developed World. The lifetime risk for developing a palpable thyroid nodule is estimated to be 5-10%, however, high-resolution ultrasound has revealed thyroid nodules in 19-68% of randomly selected individuals; the condition affects more women than men.
So if you find you have a neck/thyroid lump, don't get overly anxious! Here are some useful pointers to consider when you are faced with this lump.
A woman with a substantial neck lump
Q: Are such thyroid nodules dangerous? Can they be cancerous?
While nodular disease of the thyroid is common, malignancy of the thyroid (thyroid cancer) occurs in only 7-15% of nodules. The incidence of both thyroid nodules and thyroid malignancy has increased rapidly in recent years. Most recent data for the US indicates approximately 63,000 new thyroid cancer cases/year. This increase is thought to largely be related to early detection by high-resolution ultrasound and the discovery of sub-clinical thyroid nodules.Â
The likelihood that the increased incidence of thyroid cancer being related to early detection is supported by evidence suggesting survival rates for thyroid cancer have remained fairly stable.
While roughly 7-15% of thyroid nodules are malignant; the remainder represent a variety of benign diagnoses, including colloid nodules, degenerative cysts, hyperplasia, thyroiditis, or benign neoplasms. A rational approach to the management of a thyroid nodule is based on the clinician's ability to distinguish the more common benign diagnoses from malignancy in a highly reliable and cost-effective manner.
Q: What are the risk factors for thyroid cancer, Doc?
Risk factors for a malignant diagnosis include the following:
Age younger than 20 years or older than 70 years
Male sex
Associated symptoms of dysphagia or dysphonia
History of neck irradiation
Prior history of thyroid carcinoma
Firm, hard, or immobile nodule
Presence of cervical lymphadenopathy (enlarged neck lymph glands)
Q: What are the usual tests/investigations for a thyroid nodule?
Lab tests:
Blood test in progress
The most important laboratory test is a sensitive thyroid-stimulating hormone (TSH) assay, which is used to screen for hypothyroidism or hyperthyroidism. In addition, obtaining serum thyroxine (T4) and triiodothyronine (T3) levels may be helpful (eg, when TSH levels are low-normal or high-normal). In most cases of solitary thyroid nodules, the TSH level is normal. In cases of a solitary thyroid nodule with a normal TSH value, no additional laboratory studies may be required in the diagnostic evaluation unless an autoimmune disease (eg, Hashimoto thyroiditis) is suspected.
When the patient's history and physical findings reveal a family history or raise clinical suspicion for Hashimoto thyroiditis, obtain serum antithyroid peroxidase (anti-TPO) antibody and antithyroglobulin (anti-Tg) antibody levels. A diagnosis of Hashimoto thyroiditis does not exclude the possibility of malignancy.
Additional laboratory studies are unnecessary in the routine initial diagnostic evaluation of a solitary thyroid nodule.
Ultrasound Scans:
A lady undergoing an Ultrasound Thyroid Scan
Because of advances in technology, ultrasonography is highly sensitive in determining the size and number of thyroid nodules. By itself, ultrasonography cannot reliably distinguish a benign nodule from a malignant one. However, combining high-resolution sonography with Doppler and spectral analysis of the vascular characteristics of a thyroid nodule holds promise as a useful tool in screening thyroid nodules for malignancy. Studies have shown that the risk of malignancy is lower in nodules with a predominantly perinodular pattern than in nodules with an exclusively central vascular pattern. Furthermore, if the vascular characteristics of thyroid nodules are combined with their ultrasonographic parameters, including a halo, microcalcifications, cross-sectional diameter, and echogenicity, the predictive value of this imaging approach may increase.
Given the evidence suggesting the increase in thyroid nodule and thyroid cancer diagnosis is largely attributable to advances in high-resolution ultrasonography as well as the evidence that such imaging can have predictive value in distinguishing benign disease from malignancy, efforts to standardize thyroid ultrasound reporting have been made. Su, H et al have published a recent consensus report by a multidisciplinary panel of specialists in which recommendations for standardized thyroid ultrasound reporting have been made. These recommendations outline the characterisation of both thyroid nodules and regional lymph nodes in the neck.
Haugen et al developed the 2015 American Thyroid Association guidelines for the management of thyroid nodules in which they have stratified the estimated risk of malignancy based on specific ultrasonographic characteristics of thyroid nodules and the recommendations for those nodules which warrant biopsy based on suspicious ultrasound patterns and nodule size. Tessler et al expanded on these guidelines and proposed a risk-stratification system based on ultrasound thyroid-nodule characteristics (composition, echogenicity, shape, margin, and echogenic foci) to determine which thyroid nodules need biopsy.
Thyroid ultrasonography can be helpful in certain cases when it is used to guide Fine Needle Aspiration for Cytology or FNAC. Data have suggested that ultrasonography-guided FNAC may be preferable to palpation-guided FNAC. [10] Although sensitivity and specificity are not clear and significant between the approaches to FNAC, many authors consider image-guided FNAC to hold certain advantages. For example, image-guided FNAC may be particularly helpful in the assessment of nonpalpable or small nodules, nodules with cystic components, or nodules that are difficult to access (eg, posterior or substernal nodules). Ultrasonography-guided FNAC, combined with on-site cytologic verification of the adequacy of the specimen by a cytotechnologist or pathologist, may likely provide the highest sensitivity and specificity. Whether this is the most cost-effective approach for all thyroid nodules remains an issue.
In a study of 261 patients undergoing surgical evaluation for thyroid disease, Mazzaglia investigated whether office-based, surgeon-performed ultrasonographic examination significantly affected the operative treatment of the patients even though all of these individuals had previously undergone ultrasonographic thyroid examination. Mazzaglia reported that treatment plans for 46 patients (17.6%) were altered because of significant differences between outside and surgeon-administered ultrasonograms. In 12 patients, for example, previously unidentified nonpalpable, enlarged lymph nodes were found in the surgeon-administered ultrasonograms, with biopsy revealing metastatic thyroid cancer in 3 of these patients. Mazzaglia concluded that surgeon-performed ultrasonographic examinations can be used to make necessary changes in surgical treatment and to avoid unnecessary surgery.
Many of us ENT surgeons work closely with 1. Endocrinologist (to monitor the T4 / TSH levels) and 2. Radiologist (to perform the Ultrasound Scan and US-guided FNAC) to ascertain the type and nature of the thyroid nodule.
Fine Needle Aspiration for Cytology (FNAC)
Ultrasound-guided FNAC in progress
FNAC has emerged as the most important step in the diagnostic evaluation of thyroid nodules.
Data from numerous studies have established FNAC as highly accurate, with mean sensitivity higher than 80% and mean specificity higher than 90%. The accuracy of FNAC in diagnosing thyroid conditions highly depends on the cytopathologist's expertise and experience and the technical skill of the physician performing the biopsy. In addition, FNAC is highly cost-effective compared with traditional workups that heavily depend on nuclear imaging and ultrasonography. Routine use of FNAC in the evaluation of thyroid nodules can reduce the need for diagnostic thyroidectomy by 20-50% while increasing the yield of cancer diagnoses in thyroid specimens by 15-45%.
When the FNAC of a thyroid nodule provides adequate cellular material for analysis, the specimen can be assigned into one of several different diagnostic classifications. To improve the communication and clarity of thyroid cytopathology, the National Cancer Institute convened a conference in 2007 to address the current status of FNAC of thyroid nodules. This conference developed a consensus for terminology known as the Bethesda System for Reporting Thyroid Cytopathology. The recommended thyroid FNAC diagnostic categories in this system include benign, atypia of undetermined significance, follicular neoplasm, suspicious for malignancy, malignancy, and non-diagnostic.
The respective risk of malignancy associated with each diagnostic category is as follows:
Benign - < 1%
Atypia (AUS) - 5-10%
Follicular neoplasm - 20-30%
Suspicious for malignancy - 50-75%
Malignant - 100%
The main weakness of FNAC involves hypocellular aspirates and aspirates with high follicular cellularity. Hypocellular aspirates may be observed in cystic nodules, or they may be related to the biopsy technique. So, sometimes the FNAC is repeated.
The addition of ultrasonography to guide FNAC sometimes reduces technical errors.
Furthermore, ultrasonography guidance combined with on-site verification of the adequacy of the specimen by a cytotechnologist or a pathologist is likely to reduce the rate of nondiagnostic specimens.
Q: WHEN SHOULD YOU CONSULT YOUR GP / ENT DOCTOR?
As soon as you discover that you have a NECK/THYROID lump, you should see a Health Professional to get it checked out. As in all growths, early detection and diagnosis is crucial to early intervention and the best outcomes.
Don't wait till the lump is so big that it affects your breathing or swallowing!
You can still see older persons sometimes walking around with large neck lumps, and hopefully, these are benign (non-cancerous) in nature, allowing the patients to live so long!
When you see us in the clinic, we will take a detailed history and perform a physical examination before proceeding to the scans mentioned above and investigations to get an exact diagnosis.
We can then advise you of the various treatment options and modalities and discuss which you might want/not want to embark upon.
If you would like to make an appointment to see the doctor about your neck lump please contact us at  Euan's ENT Surgery & Clinic or call our clinic number 6694 4282.
Well, I hope this post has given you some useful pointers. If you are keen to study deeper into the topic, Here are some useful references:
REFERENCES:
Haugen BR, Alexander EK, Bible KC, Doherty GM, Mandel SJ, Nikiforov YE, et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid. 2016 Jan. 26 (1):1-133. [QxMD MEDLINE Link].
Wiltshire JJ, Drake TM, Uttley L, Balasubramanian SP. Systematic Review of Trends in the Incidence Rates of Thyroid Cancer. Thyroid. 2016 Nov. 26 (11):1541-1552. [QxMD MEDLINE Link].
Davies L, Welch HG. Current thyroid cancer trends in the United States. JAMA Otolaryngol Head Neck Surg. 2014 Apr. 140 (4):317-22. [QxMD MEDLINE Link].
Gates JD, Benavides LC, Shriver CD, et al. Preoperative thyroid ultrasound in all patients undergoing parathyroidectomy?. J Surg Res. 2008 Dec 4. [QxMD MEDLINE Link].
Mendelson AA, Tamilia M, Rivera J, et al. Predictors of malignancy in preoperative nondiagnostic biopsies of the thyroid. J Otolaryngol Head Neck Surg. 2009 Jun. 38(3):395-400. [QxMD MEDLINE Link].
Park M, Shin JH, Han BK, et al. Sonography of thyroid nodules with peripheral calcifications. J Clin Ultrasound. 2009 May 13. [QxMD MEDLINE Link].
Hong YJ, Son EJ, Kim EK, et al. Positive predictive values of sonographic features of solid thyroid nodule. Clin Imaging. 2010 March - April. 34(2):127-133. [QxMD MEDLINE Link].
Su HK, Dos Reis LL, Lupo MA, Milas M, Orloff LA, Langer JE, et al. Striving toward standardization of reporting of ultrasound features of thyroid nodules and lymph nodes: a multidisciplinary consensus statement. Thyroid. 2014 Sep. 24 (9):1341-9. [QxMD MEDLINE Link].
Tessler FN, Middleton WD, Grant EG, Hoang JK, Berland LL, Teefey SA, et al. ACR Thyroid Imaging, Reporting and Data System (TI-RADS): White Paper of the ACR TI-RADS Committee. J Am Coll Radiol. 2017 May. 14 (5):587-595. [QxMD MEDLINE Link].
Can AS. Cost-effectiveness comparison between palpation- and ultrasound-guided thyroid fine-needle aspiration biopsies. BMC Endocr Disord. 2009 May 16. 9:14. [QxMD MEDLINE Link]. [Full Text].
Mazzaglia PJ. Surgeon-Performed Ultrasound in Patients Referred for Thyroid Disease Improves Patient Care by Minimizing Performance of Unnecessary Procedures and Optimizing Surgical Treatment. World J Surg. 2010 Feb 4. [QxMD MEDLINE Link].
Heston TF, Wahl RL. Molecular imaging in thyroid cancer. Cancer Imaging. 2010 Jan 20. 10(1):1-7. [QxMD MEDLINE Link].
Vriens D, de Wilt JH, van der Wilt GJ, Netea-Maier RT, Oyen WJ, de Geus-Oei LF. The role of [(18) F]-2-fluoro-2-deoxy-d-glucose-positron emission tomography in thyroid nodules with indeterminate fine-needle aspiration biopsy: Systematic review and meta-analysis of the literature. Cancer. 2011 Mar 22. [QxMD MEDLINE Link].
Deandreis D, Al Ghuzlan A, Auperin A, et al. Is (18)F-Fluorodeoxyglucose-PET/CT Useful for the Presurgical Characterization of Thyroid Nodules with Indeterminate Fine Needle Aspiration Cytology?. Thyroid. 2012 Feb. 22(2):165-72. [QxMD MEDLINE Link].
Kundel A, Zarnegar R, Kato M, et al. Comparison of microarray analysis of fine needle aspirates and tissue specimen in thyroid nodule diagnosis. Diagn Mol Pathol. 2010 Mar. 19(1):9-14. [QxMD MEDLINE Link].
Cibas ES, Ali SZ. The Bethesda System For Reporting Thyroid Cytopathology. Am J Clin Pathol. 2009 Nov. 132(5):658-65. [QxMD MEDLINE Link].
Raparia K, Min SK, Mody DR, et al. Clinical outcomes for "suspicious" category in thyroid fine-needle aspiration biopsy: patient's sex and nodule size are possible predictors of malignancy. Arch Pathol Lab Med. 2009 May. 133(5):787-90. [QxMD MEDLINE Link].
Alexander EK, Schorr M, Klopper J, Kim C, Sipos J, Nabhan F, et al. Multicenter clinical experience with the Afirma gene expression classifier. J Clin Endocrinol Metab. 2014 Jan. 99 (1):119-25. [QxMD MEDLINE Link].
Romitelli F, Di Stasio E, Santoro C, et al. A comparative study of fine needle aspiration and fine needle non-aspiration biopsy on suspected thyroid nodules. Endocr Pathol. 2009 Summer. 20(2):108-13. [QxMD MEDLINE Link].
Gursoy A, Anil C, Erismis B, Ayturk S. Fine-needle aspiration biopsy of thyroid nodules: comparison of diagnostic performance of experienced and inexperienced physicians. Endocr Pract. 2010 Nov-Dec. 16(6):986-91. [QxMD MEDLINE Link].
Layfield LJ, Cibas ES, Gharib H, Mandel SJ. Thyroid aspiration cytology: current status. CA Cancer J Clin. 2009 Mar-Apr. 59(2):99-110. [QxMD MEDLINE Link].
Gul K, Ozdemir D, Korukluoglu B, et al. Preoperative and postoperative evaluation of thyroid disease in patients undergoing surgical treatment of primary hyperparathyroidism. Endocr Pract. 2010 Jan-Feb. 16(1):7-13. [QxMD MEDLINE Link].
[Guideline] Lebbink CA, Links TP, Czarniecka A, et al. 2022 European Thyroid Association Guidelines for the management of pediatric thyroid nodules and differentiated thyroid carcinoma. Eur Thyroid J. 2022 Dec 1. 11 (6):[QxMD MEDLINE Link]. [Full Text].
