British Thyroid Association Research Articles

The incidence of malignancy in patients with thyroid nodules

Background: Thyroid nodules are extremely common with a prevalence about 20 – 76% of adult population. Thyroid cancer is present in about 5% of nodules, even though rates as high as 15% have been reported. To determine whether the nodule is benign or malignant, fine needle aspiration biopsy (FNA biopsy) is the clinical procedure of choice.
 Objective: to evaluate thyroid nodules in order to determine the incidence of malignancy in these nodules. Patient and Methods: A prospective study was conducted among 415 patients presented with thyroid nodules in the surgical outpatient clinic in Al – Kadhimain medical city from February 2020 to February 2022. Patients between 15 t0 75 years of age, both male and female patients, were included in this study. The assessment was done by thorough history, clinical examination, thyroid profile test, neck ultrasound and fine needle aspiration cytology. After fine needle aspiration, diagnostic cytology was classified according to British Thyroid Association guidelines as THY1: non diagnostic, THY2: benign (non - neoplastic), THY3: intermediate (including follicular neoplasm), THY4: suspicion of malignancy and THY5: diagnostic of malignancy.

Suspected Malignant Thyroid Nodules in Children and Adolescents According to Ultrasound Elastography and Ultrasound-Based Risk Stratification Systems-Experience from One Center.

The risk of malignancy in thyroid nodules correlates with the presence of ultrasonographic features. In adults, ultrasound risk-classification systems have been proposed to indicate the need for further invasive diagnosis. Furthermore, elastography has been shown to support differential diagnosis of thyroid nodules. The purpose of our study was to assess the application of the American Thyroid Association (ATA), British Thyroid Association (BTA) ultrasound risk-classification systems and strain elastography in the management of thyroid nodules in children and adolescents from one center. Seventeen nodules with Bethesda III, IV, V and VI were selected from 165 focal lesions in children. All patients underwent ultrasonography and elastography followed by fine needle aspiration biopsy. Ultrasonographic features according to the ATA and BTA stratification systems were assessed retrospectively. The strain ratio in the group of thyroid nodules diagnosed as malignant was significantly higher than in benign nodules (6.07 vs. 3.09, p = 0.036). According to the ATA guidelines, 100% of malignant nodules were classified as high suspicion and 73% of benign nodules were assessed as low suspicion. Using the BTA U-score classification, 80% of malignant nodules were classified as cancerous (U5) and 20% as suspicious for malignancy (U4). Among benign nodules, 82% were classified as indeterminate or equivocal (U3) and 9% as benign (U2). Our results suggest that application of the ATA or BTA stratification system and elastography may be a suitable method for assessing the level of suspected malignancy in thyroid nodules in children and help make a clinical decision about the need for further invasive diagnosis of thyroid nodules in children.

186 Thyroid Monitoring for Patients Born After the Chernobyl Disaster Within the Blast Radius: A Literature Review

Abstract Aim There is a well-documented increase in incidence of thyroid cancer in individuals living within the blast radius at the time of the Chernobyl nuclear disaster. Following a case encountered in our clinical practice of a patient born within the blast radius but after the blast itself, we aimed to evaluate the evidence of increased thyroid cancer within such a cohort. Method We reviewed the existing literature for evidence for or against an increase in thyroid cancer in this population group. Identified articles were reviewed and appraised, evaluating the evidence for any possible increase in incidence. Results Very few papers looked at risk in such a population, but those identified suggested no increase in risk of thyroid cancer in individuals born within the radius, after the blast. Conclusions We conclude there is little evidence supporting routine monitoring for individuals born within the blast radius after the blast, and as such this should be included in the British Thyroid Association guidelines.

Have We Got Thy3 Wrong in the UK? A Four-Year Single-Site Analysis of Malignancy Rates in Thy3 Nodules.

IntroductionThyroid nodules routinely undergo ultrasound-guided fine-needle aspiration (FNA), as recommended by the National Institute for Health and Care Excellence (NICE) and the British Thyroid Association (BTA). The cytology results are classified using the “Thy” system from Thy1 to Thy5. Intermediate Thy3 FNA results are challenging, as this suggests malignancy is possible, but the relatively low rates of malignancy can make decision-making difficult. Thy3 is further subdivided into Thy3a and Thy3f.BTA recommends further ultrasound with or without FNA cytology for Thy3a nodules and hemithyroidectomy for Th3yf nodules based on a published positive predictive value (PPV) for malignancy of 17% for Thy3a and up to 40% for Thy3f results.We aim to compare the actual malignancy rates of Thy3 nodules in our unit to these figures.MethodsA retrospective study was performed looking at the histologically confirmed malignancy rates in Thy3a and Thy3f cytology over four years between January 2016 and December 2019.ResultsThere were 162 separate Thy3 nodules in 156 patients included in this study, of which 60 were classified as Thy3a and 102 as Thy3f. 10% of patients with Thy3a nodules underwent repeat cytology. The histologically confirmed malignancy rate was 33% in Thy3a and 11% in Thy3f lesions.DiscussionWe found the rates of histologically confirmed malignancy are reversed compared to the published PPVs with a higher rate in Thy3a nodules and a lower rate in Thy3f. This suggests that the surgical decision-making and patient counselling may be based on flawed data in our unit and possibly throughout the UK, making a wider study involving multiple centers desirable.

1629 The Risk of Malignancy in Cytologically Indeterminate Thyroid Nodules

Abstract Introduction Fine needle aspiration (FNA) is the gold standard for the diagnostic assessment of thyroid nodules, with cytology stratified using the Thy classification (Thy 1-5). The management of cases where cytology is indeterminate (Thy-3) is challenging and subject to controversy. The current British Thyroid Association guidelines subclassify Thy-3 lesions into Thy-3a (atypia) and Thy-3f (follicular). Repeat FNA is generally recommended for Thy-3a specimens, whilst Thy-3f lesions should proceed to diagnostic hemithyroidectomy. The aim of this study was to determine the risk of malignancy in Thy-3a and Thy-3f lesions. Method This was a retrospective study of all patients who underwent FNA of a thyroid nodule from 01/01/2018 – 31/12/19. Those with Thy-3 cytology were identified and results correlated with final surgical histology. Results In total, there were 179 patients with Thy-3 cytology: 37 Thy-3a and 142 Thy-3f. The rate of malignancy was 21.6% (n = 8) for Thy-3a lesions and 20.4% (n = 29) for Thy-3f. When excluding microcarcinoma, the rates fell to 20.4% (n = 7) and 12.7% (n = 18) respectively. There was no statistically significant difference in malignant conversion between the two groups (p = 0.20). Conclusions This study does not demonstrate any statistically significant difference in the risk of malignancy between the Thy-3a and Thy-3f groups, suggesting that this subclassification does not add any additional utility to clinical decision making. Consideration should be given to the use of local malignant conversion rates to guide further management and pre-operative patient counselling in the Thy3 group.

Microcalcifications without a thyroid nodule as the sole sign of papillary thyroid carcinoma.

SummaryOur objective is to demonstrate the importance of considering microcalcifications even without evidence of nodules as a potential sign of malignancy. Current guidelines, such as those of the British Thyroid Association, acknowledge the clinical significance of microcalcifications only when found within nodules. In this case, they are considered a suspicious feature, classifying the nodules as U5 (i.e. high risk) where fine-needle aspiration biopsy (FNAB) is warranted, following the high likelihood of cancer in these nodules. In addition, there is a dearth of evidence of ultrasound scan (USS) detection of microcalcifications in the thyroid gland outside of nodules, along with their associated clinical implications. Yet, this clinical manifestation is not so infrequent considering that we do encounter patients in the clinic showing these findings upon ultrasound examination. Three patients who presented to our clinic with thyroid-related symptoms were shown to have areas of microcalcifications without a nodule upon sonographic evaluation of their thyroid gland. These incidentally detected hyperechoic foci were later confirmed to correspond to areas of papillary thyroid carcinoma (PTC) on histopathological examination of resected tissue following thyroidectomy. Four more cases were identified with sonographic evidence of microcalcifications without nodules and given their clinical and other sonographic characteristics were managed with active surveillance instead.Learning pointsEchogenic foci known as microcalcifications may be visible without apparent association to nodular structures.Microcalcifications without nodules may not be an infrequent finding.Microcalcifications are frequently indicative of malignancy within the thyroid gland even without a clearly delineated nodule.Empirically, the usual guidelines for the management of thyroid nodules can be applied to the management of microcalcifications not confined to a nodule, but such a finding per se should be classified as a ‘high-risk’ sign.

Outcomes of 756 patients with differentiated thyroid cancer and excellent response to treatment: An evidence-based paradigm for long-term surveillance strategies.

The 2014 British Thyroid Association thyroid cancer guidelines recommend lifelong follow-up of all thyroid cancer patients. This is probably unnecessary, particularly for differentiated thyroid cancer (DTC) patients with an excellent response to treatment and places significant demand on health service resources. Single centre retrospective cohort analysis of patients diagnosed and treated at the Leeds Cancer Centre between 2001 and 2014. A total of 756 patients were dynamically risk-stratified (DRS) as having 'excellent response to treatment' after total thyroidectomy and radioiodineremnant ablation (RRA) for DTC. Median follow-up was 11.2 (range: 6.5-18.5) years. Radiological recurrence occurred in 15/756 (2.0%) patients and was always preceded by a raised thyroglobulin or thyroglobulin antibody level. The vast majority of tumour recurrences (13/15, 85%) were identifiable within 5 years of diagnostic surgery. Patients classified as having high-risk disease as per American Thyroid Association (ATA) guidelines had an almost threefold higher recurrence rate (2/34 [5.9%] vs. 13/722 [1.8%]) than those with ATA low-risk or intermediate-risk disease. Tumour histology subtype was a significant contributing factor, with Hürthle cell cancer having a worse prognosis than papillary thyroid cancer (PTC) (5/68 [7.4%] vs. 9/582 [1.5%]; relative risk: 4.76 [95% confidence interval: 1.64-13.8]). The recurrence rate of DRS patients with excellent response to treatment is low. It is reasonable to consider discharge of ATA low-risk or intermediate-risk patients with PTC who remain disease-free after 5 years of secondary care follow-up. Lifelong follow-up, however, currently remains the standard for subgroups at greater risk.

Comparison of British Thyroid Association, American College of Radiology TIRADS and Artificial Intelligence TIRADS with histological correlation: diagnostic performance for predicting thyroid malignancy and unnecessary fine needle aspiration rate

Objectives:To compare diagnostic performance of British Thyroid Association (BTA), American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) and Artificial Intelligence TIRADS (AI-TIRADS) for thyroid nodule malignancy. To determine comparative unnecessary fine needle aspiration (FNA) rates.Methods:218 thyroid nodules with definitive histology obtained during 2017 were included. Ultrasound images were reviewed retrospectively in consensus by two subspecialist radiologists, blinded to histopathology, and nodules assigned a BTA, ACR-TIRADS and AI-TIRADS grade. Nodule laterality and size were recorded to allow accurate histopathological correlation and determine which nodules met criteria for FNA.Results:77 (35.3%) nodules were malignant. Deeming ultrasound Grade 4–5 as test-positive and 1–2 as test-negative, sensitivity and specificity for BTA was 98.28 and 42.55%, for ACR-TIRADS: 95.24 and 40.57% and for AI-TIRADS: 93.44 and 45.71%. FNA was indicated in 101 (71.6%), 67 (47.5%) and 65 (46.1%) benign nodules utilising BTA, ACR-TIRADS and AI-TIRADS respectively. The unnecessary FNA rate was significantly higher with BTA (46.3%) compared to ACR-TIRADS (30.7%) and AI-TIRADS (29.8%) p < 0.001.Conclusion:BTA, ACR-TIRADS and AI-TIRADS had similar diagnostic performance for predicting thyroid nodule malignancy with sensitivity >93% for all systems when considering ultrasound Grade 4–5 as malignant and Grade 1–2 as benign. ACR-TIRADS and AI-TIRADS both had a significantly lower rate of recommended FNA in benign nodules compared to BTA.Advances in knowledge:BTA, ACR-TIRADS and AI-TIRADS have comparable diagnostic performance with high sensitivity but relatively low specificity for predicting thyroid nodule malignancy in this cohort using histology as gold-standard. Using Grade 1–2 as benign and 4–5 as malignant there were more false negatives with TIRADS but this improved when taking other features into account while BTA had a significantly higher rate of unnecessary FNA.

Ultrasound Characterization of a Solitary Thyroid Nodule According to British Thyroid Association (BTA) - Derived Criteria: A Simple Test of Reliability on a Small Cohort

Abstract Background: US-based thyroid imaging lexicons have been widely used in clinical practice for identification of FNAC-eligible thyroid nodules. A “U”-classification (BTA) was introduced in 2014 with intense researches conducted in last five years trying to test its feasibility and reliability in stratification of US thyroid nodules. Material and Methods: Prospective single-center uni-departmental study aimed at selection of only “solitary” nodules with image-analysis of US features of suspicious and non-suspicious nodules and ascribing each nodule a “U”-class in view of lexicon-provided user-friendly graphic references. Results: A small cohort, of 37 solitary nodules, was selected out of a total of 150 with comparison to FNAC aspiration cytology result according to pathology Bethesda staging. The correlation of each “U” class was compared to pathology (fine needle aspirates) and revealed very good statistical significance. Conclusion: The study suggests that a BTA (The “U”- classification) is a simple reliable test that can be feasibly practiced to select FNAC-eligible nodule amongst multi-nodular glands.

Is sonographic intra-nodular vascularity a reliable predictor of thyroid malignancy? A UK tertiary centre study.

British Thyroid Association 2014 guidelines emphasised ultrasound assessment of nodules. One ultrasonographic differentiator of debatable relevance is intra-nodular vascularity. This is the first UK study conducted to address this question. Ultrasound reports for thyroid surgery patients over 10 years were retrospectively reviewed. Reports documenting 'intra-nodular vascularity or flow' were analysed. Reports identifying peripheral vascularity only or no intra-nodular flow formed the control group. Concordance with final histology was used to determine the odds ratio for malignancy. A total of 306 patients were included, and 119 (38.9 per cent) nodules demonstrated intra-nodular vascularity. Of these, 60 (50.4 per cent) were malignant compared with 42 per cent in the control group. Intra-nodular vascularity was not a statistically significant predictor of malignancy with an odds ratio of 1.39 (p = 0.18, 95 per cent confidence interval, 0.86-2.23). Intra-nodular vascularity in isolation was not a reliable predictor of malignancy. This supports other world literature studies. Although intra-nodular flow should not be relied upon in isolation, interpretation in conjunction with other suspicious findings enhances the predictive value.

Practice patterns in management of Differentiated Thyroid Cancer since the introduction of the 2014 British Thyroid Association (BTA) Guidelines

Background: The British Thyroid Association (BTA) published updated guidelines for the management of differentiated thyroid cancer (DTC) in 2014. Previous analysis of our patient cohort suggested a significant proportion of patients may be eligible for a less aggressive approach.

Effect and long-term outcome of hemithyroidectomy for patients with low-risk papillary thyroid carcinoma

Background Although the incidence of papillary thyroid carcinoma (PTC) has increased during the recent years, most of the PTCs are slow growing and considered as low-risk tumors with an excellent prognosis. This observed increase in small tumors leads to many controversies regarding the optimal surgical approach, and the extent of surgery for low-risk PTC is still the subject of debate. Recently, there is a trend toward utilizing a less-aggressive surgical approach, including the option of hemithyroidectomy for small PTCs up to 4 cm. Patients and methods This study included 60 patients with a proven diagnosis of PTC. According to the guidelines of the British Thyroid Association, the American Thyroid Association, and the American Joint Committee on Cancer, these patients would have low-risk PTCs and considered eligible for hemithyroidectomy (total lobectomy with isthmusectomy) as an initial treatment and followed up for about 5 years to detect recurrence and survival rate. Results Hemithyroidectomy was performed as an initial treatment. Completion thyroidectomy (CTx) was performed in five (8.33%) patients in the postoperative period within 1 week after the initial operation owing to identifying high-risk features in the final histopathology. During the follow-up period of the 60 patients, there was no locoregional recurrence. Recurrence was observed in three (5%) patients in the contralateral thyroid lobe within 3–4 years and was treated with a second surgery in the form of CTx. The overall rate of CTx was eight (13.33%) of 60 patients. The prognosis and the 5-year survival rate were excellent (100%). Conclusion Hemithyroidectomy in appropriately selected patients is an optimal surgical approach for treating low-risk PTC, and if recurrence occurs in the contralateral lobe, it can be treated safely by CTx, which yielded excellent curative results.

Current surgical management of follicular thyroid carcinoma

: Follicular thyroid carcinoma (FTC) comprises a heterogenous group of tumors, which divides into subtypes with different malignant potential: minimally invasive (excellent prognosis), encapsulated angioinvasive and widely invasive FTC (higher risk metastasis and recurrence). Numerous clinical risk factors (presence of metastases, advanced patient age, tumor size and others), which can be used to assess FTC aggressiveness, are discussed with regard to the present literature. The definitive characterization of follicular neoplasms depends on postoperative histology, due to the incapability of preoperative imaging, fine-needle aspiration cytology or molecular analysis to clearly distinguish between FTC and benign follicular thyroid adenoma. In this review, treatment strategies for FTC (according to the WHO 2017 classification of endocrine neoplasms) are presented, as recommended by the leading expert societies American Thyroid Association (ATA), British Thyroid Association (BTA), German Society of Endocrine Surgery (CAEK) and European Society of Endocrine Surgery (ESES). Hemithyroidectomy is sufficient in low-risk FTC (capsular invasion only). Thyroidectomy with postoperative radioiodine therapy is recommended for high-risk FTCs (angioinvasion; widely invasive histology). Prophylactic lymphadenectomy is not necessary. Considering clinical risk factors, an individual surgical approach should be chosen, following a stepwise, escalating surgical management with restricted primary resection (hemithyroidectomy) and, if necessary, completion surgery based on the definitive histopathology.

The Added Value of Operator's Judgement in Thyroid Nodule Ultrasound Classification Arising From Histologically Based Comparison of Different Risk Stratification Systems.

Objective: Several ultrasound classifications for thyroid nodules were proposed but their accuracy is still debated, since mainly estimated on cytology and not on histology. The aim of this study was to test the diagnostic accuracy and the inter-classification agreement of AACE/ACE-AME, American Thyroid Association (ATA), British Thyroid Association (BTA), and Modena Ultrasound Thyroid Classification (MUT) that stratifies malignancy risk considering also the clinician subjective impression.Methods: A prospective study collecting thyroid nodule features at ultrasound and histological diagnosis was conducted. Ultrasound features were collected following a preformed checklist in candidates for surgery because of indeterminate, suspicious, or malignant cytology. All the nodules, besides the cytologically suspicious one, were blinded analyzed. MUT score was applied prospectively, and the others retrospectively. Sensitivity, specificity, diagnostic cut-off value, and accuracy of each classification were calculated. The overall agreement between classifications was tested by Bland-Altman, and agreement between single nodule analysis by different classifications by Weighted Cohen's Kappa.Results: In classifying a total of 457 nodules, MUT has the highest accuracy (AUC 0.808) and specificity (89%), followed by ATA and BTA, and finally by AACE/ACE-AME. ATA, BTA, and MUT are highly interchangeable. Considering agreement between single nodule analyses, ATA and BTA had the best (κ = 0.723); AACE/ACE-AME showed slight agreement with BTA (κ = 0.177) and MUT (κ = 0.183), and fair agreement with ATA (κ = 0.282); MUT had fair agreement with both ATA (κ = 0.291) and BTA (κ = 0.271).Conclusion: Classifications have an acceptable overall diagnostic accuracy, improved using a less rigid system that takes into consideration operator subjective impression.

A pragmatic assessment of the British Thyroid Association “U classification” of thyroid nodules with a focus on their follow-up

To assess the predictive value of the U classification and the significance of follow-up ultrasound in those managed conservatively. A retrospective observational study was carried out among 1,465 patients who underwent thyroid ultrasound in 2016 at a teaching hospital in UK. Details regarding U classification of nodules, cytology, histology in patients who underwent surgery, and follow-up ultrasound in those managed conservatively were obtained. Thyroid surgery was performed in 129 patients of which malignancy was seen in 35 (27.1%). The proportion of patients with cancer in U1-U5 categories were 0%, 13.6%, 30.4%, 40%, and 100%, respectively (Fisher's exact test p=0.001). There was no significant difference in U stage, cytology, or histology between incidental and symptomatic nodules. Among patients who did not undergo surgery 5% of U1, 14.6% of U2, 75% of U3, and 71.4% of U4 underwent repeat ultrasound. Radiological progression in nodule size was seen in 4.2% of U1, 1.9% of U2, 0% of U3, and 40% of U4 nodules at median duration of 306, 439, 274, and 748 days, respectively. U classification is reliable in risk-stratifying thyroid nodules. Patients with benign nodules without high-risk features do not require follow-up. The interval between scans in patients with indeterminate nodules can be extended to a period of 6-12 months.

Can ultrasound systems for risk stratification of thyroid nodules identify follicular carcinoma?

Ultrasound (US) risk stratification systems (RSSs) have been developed to reduce the number of unnecessary fine needle aspirations (FNAs) of thyroid nodules. These systems were designed primarily to identify papillary thyroid carcinomas, thus their performance on follicular thyroid carcinoma (FTC) is debatable. The present study was undertaken to investigate the accuracy of RSSs in selecting FTCs for FNA. Patients with FTC who underwent US examinations between 2012 and 2018 in 2 institutions were selected. US images were reviewed retrospectively, and FTCs were reclassified according to the American Association of Clinical Endocrinologist/American College of Endocrinology/Associazione Medici Endocrinologi (AACE/ACE/AME), American College of Radiology (ACR-TIRADS), 2015 American Thyroid Association, British Thyroid Association, European Thyroid Association, Korean Society of Thyroid Radiology and Korean Society of Radiology, and Thyroid Imaging Reporting and Data System (TIRADS). Risk class and indication for FNA were assessed. Forty-five FTCs from 45 consecutive patients were included in the study. The median tumor diameter was 32mm (range, 11-100), and ovoid isoechoic nodule with or without lobulated margins was the most frequent presentation. When FTCs were classified according to RSSs, the most common categories were intermediate and high risk, though 1 case in 3 was not classifiable. FTCs were classified as high risk/high suspicion/malignant in 11% to 74% of cases, with a statistically significant difference among the systems. FNA was indicated in 69% to 100% of cases, with good agreement among AACE/ACE/AME, ACR-TIRADS, and TIRADS. Current RSSs show high performance in selecting FTCs for FNA. This result is mainly due to the dimensional RSSs cutoffs indicating FNA. On the contrary, given the reported unsuspicious echo-structural presentation of FTC and the recognized limitation of cytological assessment to detect it, caution is advised when using US to manage cytologically indeterminate nodules.

Thy3 subclassification and indeterminate thyroid nodule surgical management

Background Cytological examination of the material obtained by fine-needle aspiration (FNA) is the best single test for differentiating malignant from benign thyroid nodules. In 2007, the British Thyroid Association introduced the ‘Thy’ classification for FNA of the thyroid to help in the management of the thyroid nodule. They suggested a plan of management for each of the Thy I to Thy V results. Aim The aim of this study was to analyze the outcomes for all Thy III results from FNA and to detect the rate of malignancy in them. Patients and methods This was a prospective study that included 24 patients who had Thy III results from fine-needle cytology. The patients were reviewed, analyzed, and operated (either lobectomy or total thyroidectomy) according to distribution of thyroid nodules. Then histopathological examination of the removed thyroid tissue was done. Results All patients in the study were reported as having Thy III in thyroid FNA. Thy IIIA was reported in six (25%) patients and the other 18 (75%) cases were categorized as having Thy IIIF. Overall, eight (33.3%) patients had right hemithyroidectomy and four (16.7%) patients had left hemithyroidectomy, whereas 12 (50%) patients had total thyroidectomy. A total of 11 (45.8%) patients were recorded as having multinodular goiter, two (8.3%) patients had nodular goiter with lymphocytic thyroiditis, seven (29.2%) patients had follicular adenoma, two (8.3%) patients were recorded as having follicular carcinoma, and two (8.3%) patients had papillary thyroid carcinoma. Conclusion Thy IIIF had a higher incidence of malignancy than Thy IIIA with a high statistically significant difference (P=0.53). It is, therefore, evident that Thy III results from FNA of the thyroid have a high risk of being malignant, but there still is a controversy regarding how to manage them, which leads to delay in treatment.

Meeting Abstracts from the 67th Annual British Thyroid Association Meeting

Meeting Abstracts from the 67th Annual British Thyroid Association Meeting

Re-audit compliance with British Thyroid Association (BTA) characterisation for thyroid nodules found on ultrasound (US)

Re-audit compliance with British Thyroid Association (BTA) characterisation for thyroid nodules found on ultrasound (US)

British Thyroid Association 2014 classification ultrasound scoring of thyroid nodules in predicting malignancy: Diagnostic performance and inter-observer agreement.

To assess the inter-observer agreement amongst five observers of differing levels of expertise in applying the British Thyroid Association (2014) guidelines for ultrasound scoring of thyroid nodules (BTA-U score) in the management of thyroid cancer, and to assess the U-score diagnostic performance in predicting malignancy. A total of 73 consecutive patients were included over a two-year period (July 2012 to July 2014), after referral to a tertiary head and neck oncology centre for ultrasound plus fine needle aspiration and cytology. Our five observers retrospectively and independently reviewed static ultrasound images on PACS and scored the thyroid nodules according to BTA-U classification. The observers were blinded to each other's scoring, cytology and histology results. Either the Kappa-statistic or intra-class correlation was used to assess the level of inter-observer agreement, plus agreement between the radiological and cytological diagnoses. The diagnostic performance of U-scoring for predicting final histological diagnosis was assessed with sensitivity, specificity, positive and negative predictive values. A Kappa-value of 0.73 (95% CI: 0.68-0.77) confirmed substantial inter-observer agreement amongst the five observers. All 17 histology confirmed malignant nodules were correctly classified as potentially malignant by all observers. The sensitivity and negative predictive value of BTA-U score in detecting and predicting malignancy were 100%, whereas the specificity and positive predictive values were 34% and 32%, respectively. There is good inter-observer agreement in using the BTA-U score amongst different observers at differing levels of expertise. Adhering to BTA-U scoring can potentially achieve 100% sensitivity in selecting malignant nodules for sampling.