The impact of thyroid nodule size on the risk of malignancy and accuracy of fine-needle aspiration: a 10-year study from a single institution

Impact of Nodule Size on Malignancy Risk Differs according to the Ultrasonography Pattern of Thyroid Nodules

Objective

To test whether the impact of thyroid-nodule size on the malignancy risk differs according to the ultrasonography (US) patterns of nodules.

Materials and Methods

This study is a post hoc analysis using data from the Thyroid Imaging Reporting and Data System (TIRADS) multicenter retrospective study which included 2000 consecutive thyroid nodules (≥ 1 cm) with final diagnoses. A total of 2000 consecutive thyroid nodules from 1802 patients (1387 women and 613 men; mean age, 51.2 ± 12.2 years) were enrolled in this study. The malignancy risk of the nodules was assessed according to the nodule size and US patterns (Korean-TIRADS).

Results

Overall, the malignancy risk did not increase as nodules enlarged. In high-suspicion nodules, the malignancy rate had no association with nodule size (p = 0.467), whereas in intermediate- or low-suspicion nodules there was a trend toward an increasing malignancy risk as the nodule size increased (p = 0.004 and 0.002, respectively). The malignancy rate of large nodules (≥ 3 cm) was higher than that of small nodules (< 3 cm) in intermediate-suspicion nodules (40.3% vs. 22.6%, respectively; p = 0.001) and low-suspicion nodules (11.3% vs. 7.0%, respectively; p = 0.035). There was a trend toward a decreasing risk and proportion of papillary carcinoma and an increasing risk and proportion of follicular carcinoma or other malignant tumors as nodule size increased (p < 0.001, respectively).

Conclusion

The impact of nodule size on the malignancy risk differed according to the US pattern. A large nodule size (≥ 3 cm) showed a higher malignancy risk than smaller nodules in intermediate- and low-suspicion nodules.

Thyroid Nodule Management: Thyroid-Stimulating Hormone, Ultrasound, and Cytological Classification System for Predicting Malignancy

Background/objectives:

Thyroid nodule (TN) is a common thyroid disorder globally, and the incidence has been increasing in recent decades. The objective of this study was to determine the contribution of thyroid-stimulating hormone (TSH), ultrasound (US), and cytological classification system for predicting malignancy among the surgically excised nodules.

Design and methods:

A retrospective analysis was performed between January 2012 and December 2014, using data drawn from 1188 patients (15-90 years), who had 1433 TN and fine-needle aspiration in Prince Sultan Military Medical City, Saudi Arabia. After reviewing all the thyroid cytopathological slides and US reports, classification was done based on the Bethesda System for Reporting Thyroid Cytology and the Thyroid Imaging Reporting and Data System (TI-RADS).

Results:

A total of 1188 patients’ medical records were reviewed for this study, among them 311 patients had undergone surgical intervention (253 patients had single nodule and 58 had 2 nodules), with a total of 369 nodules. However, as 54 nodules on the US were either unavailable or unclear, the 315 remaining nodules were analyzed, revealing 30.2% (n = 95) malignancy overall. Patients with TSH values of >4.5 mIU/L (38.2%), TN <1 cm (48.8%), TI-RADS category 5 (75.6%), and Bethesda category VI (88.9%) revealed a higher percentage of malignancy. From the univariate analysis using the χ² test, significant relationship between the TSH, nodule size, TI-RADS, and the Bethesda category between the malignant and benign nodules emerged. The regression analysis showed that patients with a TSH value of 0.5 to 4.5 mIU/L (odds ratio [OR]: 2.96), TSH >4.5 mIU/L (OR: 6.54) had higher risk for malignancy than those with a TSH value of ≤0.4 mIU/L. Thyroid nodules with sizes of 1 to 1.9 cm (OR: 1.12), 2 to 2.9 cm (OR: 0.74), 3-3.9 cm (OR: 1.21), and ≥4 cm (OR: 0.52) were found to have no association with the risk of malignancy. Compared with TI-RADS 2 patients, those with categories 4B (OR: 1.35) and 5 (OR: 2.3) were found to be at higher risk of malignancy. Similarly, Bethesda IV (OR: 2.72), V (OR: 8.47), and VI (OR: 20; P < .02) category patients had a higher risk for malignancy than those in Bethesda class I. Among the study population, the papillary thyroid carcinoma was the most common type of thyroid cancer (86, 90.5%) followed by 7.4% (n = 7) of follicular thyroid carcinoma, 1.05% (n = 1) of anaplastic carcinoma, and 1.05% (n = 1) of medullary thyroid carcinoma.

Conclusions:

A predictive model for risk of malignancy using a combining characteristic of the TSH, US, and cytological classification systems could assist the clinicians in minimizing exposing the patients with TNs to nonessential invasive procedures.

Reliability of Thyroid Imaging Reporting and Data System (TI-RADS), and ultrasonographic classification of the American Thyroid Association (ATA) in differentiating benign from malignant thyroid nodules

OBJECTIVE

Ultrasonography (US) is the best diagnostic tool for initial assessment of thyroid nodule. Recently, data reporting systems for thyroid lesions, such as the Thyroid Imaging Reporting and Data System (TI-RADS) and American Thyroid Association (ATA), which stratifies the risk for malignancy, have demonstrated good performance in differentiating malignant thyroid nodules. The purpose of this study is to determine the reliability of both data reporting systems in predicting thyroid malignancy in a tertiary care hospital.

MATERIALS AND METHODS

We evaluated 195 thyroid nodules using modified TI-RADS and ATA risk stratification. The results were compared to the cyto-pathology analysis. Histopathological results were available for 45 cases after surgery, which is considered the golden standard for diagnosis of thyroid cancer.

RESULTS

When compared with cytological results, sensitivity, specificity, negative predictive value (NPV), and accuracy were 100, 61.1, 100, and 63%, respectively, for TI-RADS; and 100, 75, 100, and 76%, respectively, for ATA. When compared with histopathological results, sensitivity, specificity, NPV, and accuracy were 90, 51.4, 94.7, and 60% respectively, for TI-RADS; and 100, 60, 100, and 68%, respectively, for ATA. All patients with malignant nodules were classified in the categories 4 or 5 of TI-RADS and in the intermediate or high suspicion risk according to the ATA system.

CONCLUSION

Both TI-RADS and the ATA guidelines have high sensitivity and NPV for the diagnosis of thyroid carcinoma. These systems are feasible for clinical application, allowing to better select patients to undergo fine-needle aspiration biopsies.

Validation of the 2015 American Thyroid Association Management Guidelines for Thyroid Nodules With Benign Cytologic Findings in the Era of the Bethesda System

OBJECTIVE

The purpose of this study is to investigate follow-up strategies for cytologically benign thyroid nodules according to size and ultrasound (US) pattern according to the 2015 American Thyroid Association (ATA) guidelines in the era of the Bethesda system.

MATERIALS AND METHODS

This retrospective study included 1208 patients with 1230 nodules that were cytologically benign at initial fine-needle aspiration performed from June 2012 to December 2014. False-negative rates (FNRs) were calculated by considering nodule size and US pattern according to the 2015 ATA guidelines and were compared between nodules with the high-suspicion US pattern and nodules with the high- or intermediate-suspicion US patterns according to size.

RESULTS

Twenty-five of the 1230 nodules (2.0%) were malignant. The FNRs were 5.1% (8/158) for nodules with the high-suspicion US pattern and 1.6% (17/1072) for nodules with other US patterns. With regard to nodule size, the FNRs were 3.2% (9/277) for nodules 3 cm or larger and 5.2% (6/115) for nodules 4 cm or larger. The FNRs of nodules with the high-suspicion pattern were not significantly higher than those of nodules with the high- or intermediate-suspicion patterns among nodules 2 cm or larger (2.5% vs 1.9%; p = 0.208), 3 cm or larger (3.4% vs 2.9%; p = 0.498), and 4 cm or larger (5.4% vs 3.8%; p = 0.353).

CONCLUSION

Thyroid nodules with initial benign cytologic findings had a low malignancy rate in the era of the Bethesda system, regardless of US pattern and size. Therefore, any immediate diagnostic intervention may be discouraged in cytologically benign nodules.

Predictors of a follicular nodule (Thy3) outcome of thyroid fine needle aspiration cytology among Saudi patients

Objective

A retrospective study was performed to evaluate predictors of thyroid fine needle aspiration cytology (FNAC) outcomes among Saudis with a thyroid nodule. Socio-demographic data, thyroid function status, thyroid parameters, ultrasound and cytology results were collected from 269 files of patients with thyroid nodules.

Result

The patients’ age was 40 ± 1.4 years (mean ± SD), and the mean body mass index (BMI) was 30.3 ± 1.2 kg/m². The thyroid statuses were euthyroid (85.5%), hypothyroidism (7.4%) and hyperthyroidism (7.1%). Young age, an absence of irradiation history, and multinodular goitre were protective against Thy3 [(OR = 0.05, CI = 003–0.6, P = 0.024), (OR = 0.4, CI = 0.2–0.8, P = 0.012) and (OR = 2.5, CI = 1.2–5.3, P = 0.016), respectively]; a lower FT3 was protective against Thy4 (OR = 0.4, CI = 0.2–0.99, P = 0.046), the absence of cervical lymphadenopathy was associated with Thy2 (OR = 2.7, CI = 1.4–5, P = 0.001), and a solid nodule was associated with Thy2 and Thy3 [(OR = 1.2, CI = 0.3–0.97, P = 0.040) and (OR = 2.2, CI = 1–4.8, P = 0.039), respectively]. In a multivariate analysis, younger age, multinodular goitre, an absence of irradiation history and cervical lymphadenopathy were protective against Thy3 [(OR = 0.04, 95% CI = 0.002–0.96, P = 0.047), (OR = 2.4, 95% CI = 1.0–5.60, P = 0.039), (OR = 0.4, 95% CI = 0.16–0.94, P = 0.036) and (O R = 0.39, 95% CI = 1–5.6, P = 0.039), respectively]. In summary, younger age, multinodular goitre, the absence of an irradiation history and cervical lymphadenopathy were protective against Thy3 in a thyroid nodule.

Large (≥3cm) thyroid nodules with benign cytology: Can Thyroid Imaging Reporting and Data System (TIRADS) help predict false-negative cytology?

Background

There is controversy about the accuracy of the fine-needle aspiration (FNA) cytology results in large sized thyroid nodules. Our aim was to evaluate the false-negative rate of FNA for large thyroid nodules and the usefulness of the Thyroid Imaging Reporting and Data System (TIRADS) in predicting false-negative cytology for large thyroid nodules with benign cytology.

Methods

632 thyroid nodules larger than or equal to 3cm in size with subsequent benign cytology on US-guided FNA were included. US features of internal composition, echogenicity, margin, calcifications, and shape were evaluated, and nodules were classified according to TIRADS. TIRADS category 3 included nodules without any of the following suspicious features:solidity, hypoechogenicity or marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, and taller-than-wide shape. Category 4a, 4b, 4c, and 5 were assigned to nodules showing one, two, three or four, or five suspicious US features, respectively. US features associated with malignancy for these lesions were analyzed and malignancy risk according to TIRADS was calculated.

Results

Of the 632 lesions, 23 lesions(3.6%) were malignant and 609(96.4%) were benign, suggesting a 3.6% false-negative rate for FNA cytology. Of the 23 malignant lesions, final pathology was mainly follicular carcinoma minimally invasive(65.2%, 15/23) and the follicular variant of papillary carcinoma(26.1%, 6/23). The malignancy risks of categories 3, 4a, 4b, and 4c nodules were 0.9%, 4.6%, 10.0%, and 11.8%, respectively.

Conclusion

Large thyroid nodules with benign cytology had a relatively high false-negative risk of 3.6% and TIRADS was helpful in predicting false-negative cytology for these lesions.

Underestimated risk of cancer in solitary thyroid nodules ≥3 cm reported as benign

BACKGROUND

The study aims to assess the risk of cancer in solitary thyroid nodules ≥30 mm in size reported as Bethesda II, and its implications.

METHOD

The clinical records of 202 patients, who underwent thyroid lobectomy for solitary nodules measuring ≥30 mm, reported as Bethesda II on preoperative FNAC between Jan 2015 and Apr 2016 were reviewed. Data collected included nodule size and consistency, and final histopathology results. The risk of cancer and the recommended management according to ATA guidelines were the outcomes of interest. Comparisons were then made between two size categories: (30-40 mm; n = 72; C1) and (>40 mm; n = 130; C2), and two nodule consistencies.

RESULTS

Mean nodule size was 43.2 mm (range 30-92). Ninety-five percent were solid and 5% were predominantly cystic. The risk of cancer was 22.8% (46/202) with no size threshold, or graded increase in risk observed. Based on biologic behavior, 50% of cancers were considered clinically significant. Accordingly, the risk of cancer for which surgery is recommended was 11.4% (23/202). The risk of cancer requiring total thyroidectomy was 9.4% and was influenced by nodule size (19 vs. 60% in C1 and C2, respectively; p = 0.01). Predominantly cystic nodules had a greater risk of malignancy compared to predominantly solid nodules even after adjusting for size (40 vs. 9.9%; p = 0.01 and 40 vs. 12.5%; p = 0.02, respectively).

CONCLUSION

The risk of malignancy in Bethesda II solitary nodules ≥30 mm is considerable implying a need for changing the way these are approached and refining cytopathology reporting.

Thyroid Nodule Size at Ultrasound as a Predictor of Malignancy and Final Pathologic Size

BACKGROUND

Thyroid-related mortality has remained constant despite the increasing incidence of thyroid carcinoma. Most thyroid nodules are benign; therefore, ultrasound and fine needle aspiration (FNA) are integral in cancer screening. We hypothesize that increased nodule size at ultrasound does not predict malignancy and correlation between nodule size at ultrasound and pathologic exam is good.

METHODS

Resected thyroids with preoperative ultrasounds were identified. Nodule size at ultrasound, FNA diagnosis by Bethesda category, size at pathologic examination, and final histologic diagnosis were recorded. Nodule characteristics at ultrasound and FNA diagnoses were correlated with gross characteristics and histologic diagnoses. Nodules for which correlation could not be established were excluded.

RESULTS

Of 1003 nodules from 659 patients, 26% were malignant. Nodules <2 cm had the highest malignancy rate (∼30%). Risk was similar (∼20%) for nodules ≥2 cm. Of the 548 subject to FNA, 38% were malignant. Decreasing malignancy rates were observed with increasing size (57% for nodules <1 cm to 20% for nodules >6 cm). At ultrasound size cutoffs of 2, 3, 4, and 5 cm, smaller nodules had higher malignancy rates than larger nodules. Of the 455 not subject to FNA, 11% were malignant. Ultrasound size alone is a poor predictor of malignancy, but a relatively good predictor of final pathologic size (R² = 0.748), with less correlation at larger sizes. In nodules subject to FNA, false negative diagnoses were highest (6-8%) in nodules 3-6 cm, mostly due to encapsulated follicular variant of papillary carcinoma.

CONCLUSIONS

Thyroid nodule size is inversely related to malignancy risk, as larger nodules have lower malignancy rates. However, the relationship of size to malignancy varies by FNA status. All nodules (regardless of FNA status) demonstrate a risk trough at ≥2 cm. Nodules subject to FNA show step-wise decline in malignancy rates by size, demonstrating that size alone should not be considered as an independent risk factor. Size at ultrasound shows relatively good correlation with final pathologic size. False negative rates are low in this series. Lesions with the appropriate constellation of clinical and radiographic findings should undergo FNA regardless of size. Both size and FNA diagnosis should influence the clinical decision-making process.

The impact of presence of Hashimoto's thyroiditis on diagnostic accuracy of ultrasound-guided fine-needle aspiration biopsy in subcentimeter thyroid nodules: A retrospective study from FUSCC

The incidence of PTMC has been increasing in the recent years. This study aimed to investigate the diagnostic value of US-FNA in thyroid nodules ≤1 cm and whether the presence of Hashimoto's thyroiditis (HT) in thyroid could influence the accuracy. The patients who accepted US-FNA at FUSCC from December 2012 to November 2015 and followed our criteria were enrolled in this study. We extracted the cytological, pathological, and follow-up US/US-FNA data of patients with subcentimeter nodules. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), false-negative rate (FNR), false-positive rate (FPR), and AUC were calculated to define FNA diagnostic performance in patients. The association of HT with cytological results was analyzed in univariate and multivariate logistic regression analysis. In total, 754 patients with 817 subcentimeter nodules were collected to comprise the FUSCC cohort. Of the 817 nodules, the cytological results were ND/UNS in 80 nodules (9.8%), benign in 74 (9.1%), AUS/FLUS in 80 (9.8%), FN/SFN in 6 (0.7%), suspicious for malignancy (SM) in 222 (27.2%), and malignant in 355 (43.5%). The sensitivity, specificity, PPV, NPV, and AUC of US-FNA for the subcentimeter nodules were 98.8%, 90.5%, 98.8%, 90.5%, and 94.7%, respectively. In comparison with HT-positive subcentimeter nodules, the diagnostic value of US-FNA for HT-negative nodules was significantly higher (HT-positive: AUC = 91.6%, HT-negative: AUC = 95.9%, P = 0.028). The coexistent HT was found to increase the risk of the FNR and indeterminate cytological results. US-FNA demonstrated an effective method for diagnosis of subcentimeter thyroid nodules with a low nondiagnostic rate in our study. The presence of HT in thyroid could be a risk factor for the increased FNR and indeterminate cytological results during US-FNA.

When Is Thyroidectomy the Right Choice? Comparison between Fine-Needle Aspiration and Final Histology in a Single Institution Experience

OBJECTIVES

The aim of this study was to compare SIAPEC-IAP-based cytological reports with their corresponding histological diagnoses to establish when thyroidectomy is the right choice in the management of thyroid diseases.

STUDY DESIGN

This is a retrospective review of all the consecutive thyroidectomies/lobectomies performed at Maria Vittoria Hospital during the 10-year period between January 2005 and December 2015. Patients who underwent both fine-needle aspiration (FNA) and surgical procedures in our institution were included in the study.

RESULTS

A total of 260 patients underwent both FNA and a thyroid surgical procedure at Maria Vittoria Hospital; 111 (42.69%) had a malignant histological report. The final cytological diagnosis was nondiagnostic (TIR-1) in 19 cases (7.31%), benign (TIR-2) in 83 cases (31.92%), indeterminate (TIR-3) in 96 cases (36.92%), suspicious for malignancy (TIR-4) in 22 cases (8.46%), and diagnostic for malignancy (TIR-5) in 40 cases (15.38%). Among the 96 cases with TIR-3 cytology, after the review, 44 (16.92%) were classified as TIR-3A and 52 (20%) as TIR-3B. The prevalence of malignancy among TIR-3A cases was 20.45% (9/44) and among TIR-3B cases 53.85% (28/52). The difference was statistically significant (p = 0.0007).

CONCLUSIONS

Our data suggest that follow-up alone is not sufficient in TIR-3A patients given the high prevalence of malignancy within that diagnostic category (20.45%) and the low sensitivity (75.68%) and specificity (59.32%) in the distinction between TIR-3A and TIR-3B. Regarding patients with a multinodular goiter and TIR-2 at FNA, the surgical approach should not be excluded.

Risk of Malignancy in Thyroid Nodules 4 cm or Larger

BACKGROUND

Several authors have questioned the accuracy of fine-needle aspiration cytology (FNAC) in large nodules. Some surgeons recommend thyroidectomy for nodules ≥4 cm even in the setting of benign FNAC, due to increased risk of malignancy and increased false negative rates in large thyroid nodules. The goal of our study was to evaluate if thyroid nodule size is associated with risk of malignancy, and to evaluate the false negative rate of FNAC for thyroid nodules ≥4 cm in our patient population.

METHODS

This is a retrospective study of 85 patients with 101 thyroid nodules, who underwent thyroidectomy for thyroid nodules measuring ≥4 cm.

RESULTS

The overall risk of malignancy in nodules ≥4 cm was 9.9%. Nodule size was not associated with risk of malignancy (odds ratio, 1.02) after adjusting for nodule consistency, age, and sex (P=0.6). The false negative rate for FNAC was 0%.

CONCLUSION

Nodule size was not associated with risk of malignancy in nodules ≥4 cm in our patient population. FNAC had a false negative rate of 0. Patients with thyroid nodules ≥4 cm and benign cytology should not automatically undergo thyroidectomy.

Molecular Profiling of Thyroid Nodules: Current Role for the Afirma Gene Expression Classifier on Clinical Decision Making

Thyroid fine-needle aspiration biopsy results are cytologically indeterminate in 15-30% of cases. When these nodules undergo diagnostic surgery, approximately three-quarters are histologically benign. These unnecessary surgeries diminish quality of life, generate complications, and increase healthcare costs. The Afirma gene expression classifier (GEC) is validated to pre-operatively identify cytologically indeterminate nodules likely to be truly benign so that surgery can be avoided. Its performance is supported by robust multicenter prospective and blinded clinical validation studies, and supported by extensive independent clinical utility publications which show a marked reduction in surgery among patients with benign Afirma GEC results. To rule-out cancer and avoid unnecessary diagnostic surgery, Afirma’s quality and depth of validation stand alone. The accuracy of a benign result is the negative predictive value (NPV). Afirma achieves an NPV ≥94% among cytologically indeterminate nodules (Bethesda III or IV). Thirteen clinical utility studies describing 1468 GEC benign patients demonstrate that few Afirma GEC benign nodules undergo surgery, including after 3 years of follow-up. With a specificity of 52%, over half of the truly benign nodules with indeterminate cytology receive a benign GEC result. High test sensitivity is critical to safely rule out cancer. The Afirma GEC’s 90% sensitivity means that regardless of the pre-test risk of malignancy, 90% of all malignant nodules are GEC suspicious. The Afirma GEC has transformed patient care. Where the majority of cytologically indeterminate patients were once operated to determine if the nodule was benign or malignant, now nearly half of these surgeries can be avoided.

Increased Chromosomal and Oxidative DNA Damage in Patients with Multinodular Goiter and Their Association with Cancer

Thyroid nodules are a common clinical problem worldwide. Although thyroid cancer accounts for a small percentage of thyroid nodules, the majority are benign. 8-Hydroxy-2'-deoxyguanosine (8-OHdG) levels are a marker of oxidative stress and play a key role in the initiation and development of a range of diseases and cancer types. This study evaluates cytokinesis-block micronucleus cytome (CBMN-cyt) assay parameters and plasma 8-OHdG levels and their association with thyroid nodule size and thyroid hormones in patients with multinodular goiter. The study included 32 patients with multinodular goiter and 18 age- and sex-matched healthy controls. CBMN-cyt assay parameters in peripheral blood lymphocytes of patients with multinodular goiter and controls were evaluated, and plasma 8-OHdG levels were measured. The micronucleus (MN) frequency (chromosomal DNA damage), apoptotic and necrotic cells (cytotoxicity), and plasma 8-OHdG levels (oxidative DNA damage) were significantly higher among patients with multinodular goiter. Our study is the first report of increased chromosomal and oxidative DNA damage in patients with multinodular goiter, which may predict an increased risk of thyroid cancer in these patients. MN frequency and plasma 8-OHdG levels may be markers of the carcinogenic potential of multinodular goiters and could be used for early detection of different cancer types, including thyroid cancer.

Risk of Malignancy in Thyroid Nodules with Non-Diagnostic Fine-Needle Aspiration: A Retrospective Cohort Study

BACKGROUND

Fine-needle aspiration (FNA) of thyroid nodules is commonly performed, and despite the use of ultrasound (US) guidance, the rate of non-diagnostic FNAs is still significant. The risk of malignancy of thyroid nodules with a non-diagnostic FNA is not clearly defined. However, most studies exclude the majority of patients without a repeat biopsy or surgery, thus increasing the likelihood of selection bias. The aims of this study were to determine the malignancy risk in nodules with an initial non-diagnostic FNA, and to identify the factors associated with malignancy.

METHODS

This was a retrospective cohort study of patients with thyroid nodules who underwent US-guided FNA between 2004 and 2010 and had a non-diagnostic result. Patients were followed until confirmatory diagnosis of the nature of the nodule was made. The outcome of malignant or benign disease was based on one of the following: (i) final surgical pathology following thyroidectomy; (ii) repeat biopsy; (iii) clinically, based on repeat ultrasound performed at least three years following biopsy; or (iv) report of thyroid status for patients without follow-up visits contacted by mail.

RESULTS

There were 699 nodules from 665 patients included. The mean age was 59 ± 15 years, and 71.7% were women. There was complete follow-up of 495 nodules. After a median follow-up of 2.7 years, thyroid cancer was found in 15 nodules. The prevalence of malignancy was 3% (15/495). The presence of nodular calcifications was the strongest predictor of thyroid malignancy (odds ratio 5.03 [confidence interval 1.8-14.7]). Initial nodule size was inversely associated with malignancy (odds ratio 0.55 [confidence interval 0.28-0.93]). However, the 193 patients without follow-up had smaller nodules compared with those included in the analysis. None of the patients with repeatedly non-diagnostic results were diagnosed with thyroid cancer at follow-up.

CONCLUSION

The prevalence of thyroid cancer in nodules with non-diagnostic results is lower than the malignancy rate in thyroid nodules in general, but not negligible. They should be followed as per guidelines with heightened suspicion for nodules containing calcifications. Nodules with repeatedly non-diagnostic FNA results especially in the absence of calcifications have a low risk of malignancy and may be observed.

Bethesda classification is a valuable guide for fine needle aspiration reports and highly predictive especially for diagnosing aggressive variants of papillary thyroid carcinoma

BACKGROUND

A fine needle aspiration biopsy (FNAB) is the most valuable diagnostic procedure for pre-operative discrimination of benign and malignant nodules. The Bethesda System for Reporting Thyroid Cytopathology provides standardised reporting and cytomorphological criteria in aspiration smears. The aim of the present study was to determine malignancy rates in nodules with different cytology results and evaluate the diagnostic value of Bethesda for variants of papillary thyroid carcinoma (PTC).

MATERIALS AND METHODS

A retrospective analysis of 2534 cases with 5784 thyroid nodules, who underwent FNAB followed by surgery, were included in this study. FNAB was performed with ultrasonography guidance. Cytological diagnoses were classified as: non-diagnostic (ND), benign, atypia of undetermined significance/follicular lesions of undetermined significance (AUS/FLUS), follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), suspicious for malignancy (SUS) and malignant. Histopathological diagnoses were classified into four groups: benign, PTC, follicular thyroid cancer and other types of thyroid cancer (including medullary thyroid cancer, undifferentiated thyroid cancer and thyroid tumours of uncertain malignant potential). Cases with PTC were further divided into four categories: conventional variant, follicular variant, aggressive variants (tall cell, diffuse sclerosing and columnar variant) and other variants (oncocytic, solid/trabecular and warthin-like variants). FNAB results were compared with histopathological results.

RESULTS

Malignancy rates were 6.3%, 3.2%, 20.7%, 33.3%, 74.2% and 95.6% in the nodules with ND, benign, AUS/FLUS, FN/SFN, SUS and malignant cytology results, respectively. Pre-operative cytology was malignant or SUS in 56.6% of conventional, 24.3% of follicular, 92% of aggressive and 41.7% of other variants of histopathologically confirmed PTC. The difference between the groups was significant (P < 0.001).

CONCLUSION

The Bethesda classification is a reliable indicator of malignancy in nodules with different cytology results and seems to be very effective in predicting the malignancy for the nodules diagnosed with aggressive variant PTC on the final histological examination.

Clinical Factors Influencing the Performance of Gene Expression Classifier Testing in Indeterminate Thyroid Nodules

BACKGROUND

Molecular diagnostic testing is increasingly used in the management of indeterminate thyroid nodules. Limited data exist regarding the influence of clinical factors on gene expression classifier (GEC) test performance. This study examined the positive and negative predictive value of GEC as stratified by nodule size.

METHODS

A prospectively maintained pathology database from a single tertiary referral center was queried from 2012 to 2015 for indeterminate thyroid nodules that underwent GEC testing. Nodule size, patient demographics, Bethesda classification, and Hürthle cell-predominant nodules (HCNs) were evaluated as predictors of GEC performance.

RESULTS

Two hundred and thirty-one patients with 245 indeterminate nodules were examined. Assuming all nodules to be benign unless proven malignant on histopathology, the sensitivity and specificity of GEC testing were 95.2% and 60.1%, respectively. The malignancy rate among resected nodules was 25.3%. The positive predictive value was consistent across nodule sizes: 45.5% for nodules <1 cm, 42.9% for nodules 1-1.9 cm, 36.0% for nodules 2-2.9 cm, 54.2% for nodules 3-3.9 cm, and 50.0% for nodules ≥4 cm. The negative predictive value ranged from 93.3% to 100% and was not affected by nodule size. HCNs had a high rate of GEC suspicious results (77.4% vs. 50.5% for nodules without Hürthle cell predominance, p < 0.01), though this did not correspond to a difference in the rate of malignancy (25.8% vs. 25.3%).

CONCLUSIONS

Nodule size did not affect GEC test performance in the present cohort. GEC benign results remain reliable in large nodules. GEC suspicious nodules >3 cm carry a similar risk of malignancy compared to smaller nodules, and do not warrant more aggressive treatment. GEC testing has limited clinical utility for HCNs due to the high rate of false-positive results.

Value of fine-needle aspiration in evaluating large thyroid nodules

BACKGROUND

The American Thyroid Association (ATA) recommends using ultrasound-guided fine-needle aspiration (FNA) in order to evaluate supracentimetric and suspect thyroid nodules. The purpose of this study was to evaluate the effective use of FNA before surgery for nodules over 3 cm in diameter.

METHODS

In this retrospective study, we analyzed the results of ultrasound-guided FNA and postoperative histological analysis in 843 nodules >3 cm.

RESULTS

The FNA was informative in 42.6%. The correlation with the final histological analysis was 94.8% for benign nodules and 71.0% for malignant nodules. The FNA had a positive predictive value of 71%, a specificity of 97%, a sensitivity of 56%, and a 4.7% rate of false-negative results.

CONCLUSION

Because there is a nonnegligible FNA risk of error, notably allowing the evolution of a cancer in 1 of 20 cases, the FNA data should not delay surgical intervention for potentially suspect nodules >3 cm in diameter. © 2016 Wiley Periodicals, Inc. Head Neck 39: 32-36, 2017.

A meta-analysis examining the independent association between thyroid nodule size and malignancy

BACKGROUND

Tumor size is recognized as an important predictor of malignancy in many types of cancers. However, there is no clear line of characterization when it comes to the association between thyroid nodule size and malignancy risk prediction; and the current data remains inconsistent across different studies. The aim of our study is to examine the association between nodule size and malignancy using meta-analysis of the current literature.

METHODS

Data sources were gathered through systemic search of PubMed, Embase and other scientific databases for articles published between January 1, 1996 and June 1, 2013. A reference group with nodule sizes <3 cm was set as a control group. Two other nodule size categories were established and these included nodules from 3-5.9 cm and nodules ≥6 cm in size. Primary outcome was a histologically proven malignancy per nodule size category. The effect sizes of clinicopathologic parameters, which are the quantitative measures of association strength between two variables, were calculated by the means of odds ratios (OR). The effect sizes were then combined using a random-effects model.

RESULTS

Seven studies met our inclusion criteria with 10,817 thyroid nodules evaluated. Malignancy was identified in 2,206 (20.4%) nodules. After adjusting for patient age and gender, nodules that measured 3-5.9 cm had a 26% greater malignancy risk compared to those measuring <3 cm [OR, 1.26; 95% confidence interval (CI): 1.13-1.39]. However, nodules 6 cm or larger had a 16% lower risk of malignancy compared to those measuring <3 cm (OR, 0.84; 95% CI: 0.73-0.98).

CONCLUSIONS

Thyroid nodule size predicts cancer risk. However, a threshold effect of thyroid nodule size 6 cm or greater is significantly associated with a more benign disease.

An online questionnaire survey on preferred timing for the diagnosis and management of thyroid carcinoma in general population in Korea

PURPOSE

An optimal timing for diagnosis and management of papillary thyroid microcarcinoma (PTMC) has become the subject for much controversy. The aim of the present study is to analyze people's preference in Korea for timing of diagnosis and management of PTMC using an online questionnaire.

METHODS

The questionnaire consists of 3 questions about preference for the diagnosis and management of PTMC and 3 additional questions about respondents' personal information. An online survey was conducted from March 3 to June 3 in 2015 using Google Survey (http://goo.gl/forms/b81yEjqNUA).

RESULTS

A total 2,308 persons (1,246 males, 1,053 females) answered the questionnaire. Respondents' ages varied widely from teenagers to 70-year-olds. If there was a suspicious thyroid nodule from PTMC measuring less than 1 cm in diameter, 95.7% of respondents want to know a cytological diagnosis for it. If a thyroid nodule turned out to be a PTMC, 59.5% of respondents wanted it removed immediately. For surgical management of PTMC, 53.0% of respondents were worried more about recurrences than complications. In subgroup analyses, respondents younger than 40 years old more often want immediate surgery than others: 66.7% vs. 32.7% (P < 0.05). Respondents who underwent thyroid cancer surgery (n = 91) were worried more about recurrences than others: 69.2% vs. 52.4% (P < 0.05).

CONCLUSION

Almost all respondents in the present study wanted diagnosis of suspicious thyroid nodules immediately. However, there were opposing opinions about the preferred timing for surgical treatment and surgical extents. A patient's right to know their disease status and decision on treatments should be emphasized all the more.

Malignancy risk and false-negative rate of fine needle aspiration cytology in thyroid nodules ≥4.0 cm

BACKGROUND

We aimed to evaluate malignancy rate and to determine false negativity of fine needle aspiration biopsy (FNAB) in thyroid nodules ≥4.0 cm.

METHODS

The medical records of patients who underwent thyroidectomy between January 2007 and December 2014 were reviewed. Demographic and clinical data as well as preoperative ultrasonography findings were analyzed. The nodules in these patients were grouped as ≥4.0 cm and <4.0 cm according to ultrasonography measurements. Nodules <4.0 cm were further divided into 1.0-3.9 cm and <1.0 cm. Histopathologically malignant nodules with preoperative benign cytology were defined as having false-negative FNAB.

RESULTS

There were 1,008 nodules that measured ≥4.0 cm, 4,013 nodules that measured 1.0-3.9 cm, and 540 that measured nodules <1.0 cm. Based on histopathologic findings, 8.5%, 10.2%, and 25.6% of nodules ≥4.0 cm, 1.0-3.9 cm, and <1.0 cm were malignant, respectively (P < .001). There was no significant difference between 1.0-3.9-cm and ≥4.0-cm nodules with respect to malignancy (P = .108). False-negativity rates were 4.7% in nodules ≥4.0 cm, 2.2% in nodules measuring 1.0-3.9 cm, and 4.8% in <1.0-cm nodules. Nodules measuring <1.0 cm and ≥4.0 cm had similar false-negativity rates (P = .93), while 1.0-3.9-cm nodules had statistically lower false-negativity rates than those found in the other two groups (P = .03 and P < .001, respectively).

CONCLUSION

Of the nodules that were operatively excised, nodules ≥4.0 cm had a similar risk of malignancy as nodules 1.0-3.9 cm. The rate of false-negative FNAB in nodules ≥4.0 cm was twice as high as in nodules 1.0-3.9 cm; however, we do not think it is high enough to recommend a routine operation when cytology results are benign.

Ultrasonography Diagnosis and Imaging-Based Management of Thyroid Nodules: Revised Korean Society of Thyroid Radiology Consensus Statement and Recommendations

The rate of detection of thyroid nodules and carcinomas has increased with the widespread use of ultrasonography (US), which is the mainstay for the detection and risk stratification of thyroid nodules as well as for providing guidance for their biopsy and nonsurgical treatment. The Korean Society of Thyroid Radiology (KSThR) published their first recommendations for the US-based diagnosis and management of thyroid nodules in 2011. These recommendations have been used as the standard guidelines for the past several years in Korea. Lately, the application of US has been further emphasized for the personalized management of patients with thyroid nodules. The Task Force on Thyroid Nodules of the KSThR has revised the recommendations for the ultrasound diagnosis and imaging-based management of thyroid nodules. The review and recommendations in this report have been based on a comprehensive analysis of the current literature and the consensus of experts.

DO ALL THYROID NODULES >4 CM NEED TO BE REMOVED? AN EVALUATION OF THYROID FINE-NEEDLE ASPIRATION BIOPSY IN LARGE THYROID NODULES

OBJECTIVE

Controversy exists regarding the ability of fine-needle aspiration (FNA) biopsy to rule out malignancy when thyroid nodules exceed 4 cm in diameter. The goal of this study was to provide data regarding FNA accuracy in a clinical setting for detecting/ruling out malignancy in large thyroid nodules (≥4 cm) and discuss FNA utility in guiding surgical decisions.

METHODS

All thyroid FNA cases performed at Marshfield Clinic from 1/1/2000 to 12/31/2010 followed by complete or partial thyroidectomy on nodules of at least 4 cm were identified. Demographics, medical history, nodule biopsy characteristics, surgical procedures, and diagnosis data were abstracted. FNA was compared to histologic evaluation of surgical specimens.

RESULTS

A total of 198 patients with large thyroid nodules were identified. Most had a single large nodule, but ~40% were multinodular, and 206 total nodules were assessed. Females outnumbered males, and the mean age was ~50 years. After surgery, cancer was histologically identified in 49/206 (23.8%) nodules, including 9/123 nodules that had been categorized as benign by FNA, corresponding to a false-negative rate of 7.3%. Sensitivity/specificity for detecting malignancy by FNA was ~80%. The positive predictive value (PPV) was just below 60%, and the negative predictive value (NPV) was 93% but rose to 96% when papillary microcarcinomas were excluded.

CONCLUSION

While FNA sensitivity in large nodules was relatively low, NPV was high, especially if incidental papillary microcarcinomas were excluded. When cancer prevalence and NPV are known, FNA can be a reliable "rule out" test in nodules ≥4 cm. This information is critical and can help guide the surgery decision, especially in high-risk patients. The decision for surgery should not be solely based on nodule size but should consider additional factors including cancer prevalence, clinical history, ultrasound features, surgical risk, and life expectancy.

ABBREVIATIONS

FNA = fine-needle aspiration NPV = negative predictive value PPV = positive predictive value.

Does Tumor Size Influence the Diagnostic Accuracy of Ultrasound-Guided Fine-Needle Aspiration Cytology for Thyroid Nodules?

Background. Fine-needle aspiration cytology (FNAC) is diagnostic standard for thyroid nodules. However, the influence of size on FNAC accuracy remains unclear especially in too small or too large thyroid nodules. The objective of this retrospective cohort study was to investigate the effect of nodule size on FNAC accuracy. Methods. All consecutive patients who underwent thyroidectomy for nodules in 2010 were enrolled. FNAC results (according to the Bethesda system) were compared to pathological diagnosis. The nodules were categorized into groups A-E on the basis of maximal diameter on ultrasound (≤0.5, >0.5-1, >1-2, >2-4, and >4 cm, resp.). Results. There were 502 cases with 690 nodules. Overall FNAC sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 95.4%, 98.2%, 99.4%, 86.4%, and 96.0%, respectively. False-negative rates (FNRs) of groups A-E were 3.2%, 5.1%, 1.3%, 13.3%, and 50%, respectively. Accuracy rates of groups A-E were 96.8%, 94.8%, 99%, 94.7%, and 87.5%, respectively. Conclusion. Although accuracy rates of FNAC in thyroid nodules smaller than 0.5 cm are comparable to the other group, thyroid nodules larger than 4 cm with benign cytology carry a higher risk of malignancy, which suggest that those should be considered for intensive follow-up or repeated biopsy.

Outcome of Subclassification of Indeterminate (Thy-3) Thyroid Cytology into Thy-3a and Thy-3f

OBJECTIVES

The British Thy system is a widely used classification system for reporting thyroid fine-needle aspiration (FNA) cytology. The Royal College of Pathologists in 2009 recommended the subdivision of the Thy-3 (indeterminate) category into Thy-3a (atypia) and Thy-3f (follicular neoplasm). Our objective was to examine the malignancy rates of Thy-3a and Thy-3f cases at our institution and to investigate whether the risk of malignancy in Thy-3a cases is reduced by FNA on a different occasion showing benign cytology.

METHODS

This is a retrospective study of 748 thyroid nodules undergoing 1,032 FNAs, with indeterminate (Thy-3) cytology subdivided into Thy-3a and Thy-3f. Cases were correlated with final histology in surgical cases. Incidental carcinomas occurring outside the biopsied nodule were discounted.

RESULTS

A total of 109 nodules had a final cytological diagnosis of Thy-3a, of which 67 underwent surgery, with an incidence of malignancy of 13.4% (9/67); 90 nodules had a final cytological diagnosis of Thy-3f, of which 84 underwent surgery, with an incidence of malignancy of 17.9% (15/84). The difference in malignancy rates was not significant (p = 0.51). The incidence of malignancy in nodules with benign and Thy-3a cytology on separate occasions was not significantly different from cases with a single Thy-3a cytology.

CONCLUSIONS

Thyroid nodules with Thy-3a cytology have a slightly lower risk of malignancy than Thy-3f cases. However, the difference is not significant and does not appear to be reduced by FNA on a separate occasion showing benign cytology. Management decisions for patients with Thy-3a cytology should be taken carefully to avoid missing cancers.

Factors associated with the sensitivity of fine-needle aspiration cytology for the diagnosis of follicular variant papillary thyroid carcinoma

BACKGROUND

The purpose of this study was to evaluate the factors associated with diagnostic accuracy of preoperative fine-needle aspiration (FNA) for follicular variant papillary thyroid carcinoma (FVPTC).

METHODS

The patients with FVPTC who underwent thyroidectomy were divided into 2 groups: "group A" (Bethesda category II, III, or IV) versus "group B" (category V or VI).

RESULTS

A total of 225 patients (117 in group A and 108 in group B) were included. Group B was associated with older age, malignant ultrasonographic features, smaller tumor size, extrathyroidal extension, higher stage, and B-type Raf (BRAF)(V600E) mutation compared with group A. In multivariable analysis, malignant ultrasonographic features and tumor size ≤3.0 cm were independent predictive factors for group B.

CONCLUSION

FVPTCs >3.0 cm are unlikely to be diagnosed as category V or VI. Clinicians should keep FVPTC in mind and consider diagnostic lobectomy for the nodules regardless of FNA or ultrasonographic findings. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1467-E1471, 2016.

Impact of Microcalcifications on Risk of Malignancy in Thyroid Nodules with Indeterminate or Benign Cytology

Objective

Adverse sonographic features such as microcalcification may predict increased likelihood of malignant cytology by fine-needle aspiration and, accordingly, increased risk of malignant histology. Our objective was to study the predictive value of microcalcifications and other sonographic features for malignancy among thyroid nodules with benign or indeterminate cytology.

Study Design

Case series with chart review.

Setting

Academic teaching hospital.

Subjects

Patients (N = 769) with 858 thyroid nodules undergoing 1142 ultrasound fine-needle aspirations; 411 cases had surgical correlation.

Methods

Sonographic features predictive of malignancy were correlated with malignancy as determined by histology. Incidental malignancies occurring outside the index nodule were discounted.

Results

Cytology was inadequate (87 cases), benign (518), indeterminate (210), and malignant (44). In 32 cases, initial benign cytology was upgraded to a higher-risk category after repeat ultrasound fine-needle aspiration. Microcalcification ( P = .001) and irregular margins ( P = .04) were significantly predictive of malignant cytology. Among surgical cases, microcalcification ( P < .001) and irregular margins ( P = .04) were significantly predictive of malignant histology; 170 patients with initial benign cytology and 161 with indeterminate cytology underwent surgery. Microcalcification was significantly associated with malignancy among cases with indeterminate cytology ( P = .04) but not among cases with benign cytology ( P = .23); however, only 13 of 33 cases with benign cytology and microcalcifications underwent surgery.

Conclusion

Presence of microcalcification increases the risk of malignancy in thyroid nodules with indeterminate cytology and may thus aid in selection of cases for surgery.

Is an Increase in Thyroid Nodule Volume a Risk Factor for Malignancy?

BACKGROUND

Most benign thyroid nodules found on fine-needle aspiration cytology (FNAC) can be followed with periodic ultrasonography. During follow-up, when nodules grow, re-aspiration or surgical resection for a histologic diagnosis is recommended. However, there is little evidence regarding the malignancy risk associated with nodule growth.

METHOD

We retrospectively reviewed the records of 542 patients with FNAC-diagnosed adenomatous nodules (ANs) who underwent surgery in 2011-2012 at Kuma Hospital. Among them, 196 patients had surgical resection because of nodule volume growth (median, 1.94 times; range, 1.21-27.60) during the observation period (mean, 45.9 months). Excluding nodule growth, the remaining 346 patients underwent surgery for various reasons including the large size of nodules or the appearance of undefined ultrasound features suspicious for malignancy during follow-up. For comparison, we reviewed 409 patients with FNAC-diagnosed follicular neoplasms (FNs) operated on in 2011-2013. Most (n=327) underwent surgery shortly after the FNAC diagnosis, while 82 patients were observed for a period of time and had a late operation due to nodule volume growth (median, 2.70 times; range, 1.27-15.82).

RESULTS

The histologic diagnoses of the 196 growing FNAC-diagnosed ANs were 158 ANs, 32 follicular adenomas (FAs), 4 follicular tumors of uncertain malignant potential (FT-UMP; 2%), and 2 malignancies (1%). The 346 patients who underwent surgery for reasons other than nodular growth had 16 FT-UMP (4.6%) and 16 malignancies (4.6%). This suggests that nodule growth itself is not a risk factor for malignancy. On the other hand, there were 23 FT-UMP (28%) and 15 malignancies (18.3%) in the 82 growing FNAC-diagnosed FNs, while 44 FT-UMP (13.5%) and 54 malignancies (16.5%) in the 327 FNAC-diagnosed FN patients who underwent immediate surgery. The malignant potential was significantly higher in the growing-FN group than the immediate-surgery FN group (p<0.05). No significant difference was found in the volume change between the benign and the FT-UMP plus malignant group in the growing FNs, suggesting that a growth rate does not correlate with malignant potential.

CONCLUSION

This is the first demonstration that the malignancy risk is low in FNAC-diagnosed ANs, even if the nodules grow significantly, whereas FNs have a higher risk when they grow.

The diagnostic accuracy of ultrasound-guided fine-needle aspiration biopsy for thyroid nodules three centimeters or larger in size

BACKGROUND AND PURPOSE

Whether under ultrasonography (US) guidance or not, fine-needle aspiration biopsy (FNAB) has some limitations, particularly in larger nodules. In this study, we aimed to evaluate the diagnostic value of US-guided fine-needle aspiration biopsy (US-FNAB) in thyroid nodules equal to or larger than 3 cm.

MATERIALS AND METHODS

Data of 267 patients operated for nodular goiter in the period of January 2006 and March 2012 were reviewed retrospectively. The study group (40 males, 104 females; mean age 42.3 ± 12.3, between 17 and 71) consisted of patients with nodules with a diameter of 3 cm or larger. Patients with nodules less than 3 cm in diameter were considered as the control group (27 males, 96 females; mean age 44.4 ± 11.9, between 18 and 71).

RESULTS

For nodules smaller than 3 cm, US-FNAB had an accuracy rate of 60% and a false negativity rate of 21.9%. In nodules equal to or larger than 3 cm, the accuracy rate of US-FNAB was 80%, with a false negativity rate of 6.7%. Malignancy was observed in 16% of the study group and 42.3% of the control group.

CONCLUSION

This study showed that increased nodule diameter is not associated with limitations in the diagnostic value of US-FNAB. We also found that the malignancy rate was smaller for larger nodules. This finding reflects the importance of accurate and rational diagnostic work-up and clinical management for detecting malignancy and surgical decision-making.

Factors Influencing the Reliability of Thyroid Fine-Needle Aspiration: Analysis of Thyroid Nodule Size, Guidance Mode for Aspiration and Preparation Method

OBJECTIVE

We aimed to clarify the influence of ThinPrep preparation, nodule size and guidance mode on the accuracy of thyroid fine-needle aspiration (FNA).

METHODS

A total of 1,240 thyroid FNAs were reviewed and 489 cases with histological correlations were enrolled in this study.

RESULTS

Of the 489 total cases examined, 101 were processed with both ThinPrep and conventional preparation and 388 entirely with ThinPrep. The overall nondiagnostic rate, sensitivity and accuracy of FNA were 2.0, 91.0 and 89.4%, respectively. The cases with a preoperative ultrasound (n = 469) were grouped according to nodule size. The nondiagnostic rate, sensitivity and accuracy of FNA did not differ significantly with nodule size (p1 = 0.339, p2 = 0.179, p3 = 0.119). A total of 101 resections were performed with palpation-guided FNA and 388 were performed with ultrasound-guided FNA. The nondiagnostic rates, sensitivity and accuracy of FNA were similar in these two groups.

CONCLUSIONS

The ThinPrep technique is a valid method for thyroid FNA and is effective for thyroid nodules ≥ 0.5 cm. The reliability of FNA results is not reduced with larger nodules. The use of palpation-guided FNA for palpable solid nodules is also effective.

The Validity of Ultrasonography-Guided Fine Needle Aspiration Biopsy in Thyroid Nodules 4 cm or Larger Depends on Ultrasonography Characteristics

BACKGROUND

The objective of this study was to evaluate the validity of fine needle aspiration biopsy (FNAB) according to ultrasonography (US) characteristics in thyroid nodules 4 cm and larger.

METHODS

We retrospectively reviewed the cases of 263 patients who underwent thyroid surgery for thyroid nodules larger than 4 cm between January 2001 and December 2010.

RESULTS

The sensitivity of US-FNAB was significantly higher in nodules with calcifications (micro- or macro-) than those without (97.9% vs. 87.% P<0.05). The accuracy of US-FNAB was higher in large thyroid nodules with US features suspicious of malignancy, such as a solid component, ill-defined margin, hypoechogenicity or marked hypoechogenicity, or any calcifications (micro- or macro-) compared to thyroid nodules with none of these features. Furthermore, the accuracy improved as the number of these features increased. The overall false negative rate (FNR) was 11.9%. The FNR of thyroid nodules that appeared benign on US, such as mixed nodules (7.7%) or nodules without calcification (9.8%), trended toward being lower than that of solid nodules (17.9%) or nodules with any microcalcification or macrocalcification (33.3%). In nodules without suspicious features of malignancy, the FNR of US-FNAB was 0% (0/15).

CONCLUSION

We suggest individualized strategies for large thyroid nodules according to US features. Patients with benign FNAB can be followed in the absence of any malignant features in US. However, if patients exhibit any suspicious features, potential false negative results of FNAB should be kept in mind and surgery may be considered.

Is primary hyperparathyroidism a risk factor for papillary thyroid cancer? An exemplar study and literature review

Introduction Primary hyperparathyroidism (PHPT) is associated with several cancer types, including papillary thyroid carcinoma (PTC). Objective To explore further the relation between PHPT and PTC. Methods By considering patients with PHPT as extra-suspicious for PTC, we studied an exemplar group of patients with PHPT with a small (≤1 cm) thyroid nodule, which was negative in preoperative cytologic examination. During parathyroidectomy, a frozen section biopsy of the thyroid nodule confirmed PTC, as did the final surgical specimen, revealing that the preoperative cytology was false-negative. Additionally, relevant reports retrieved from the English literature addressing thyroid cancer and hyperparathyroidism were reviewed and processed. Results Four patients with PHPT were studied. Three had a multifocal thyroid disease, and three had neck lymph node metastasis. Processing previous report data supported an association between PHPT and PTC. Although thyroid nodularity among patients with PHPT was similar to the general population, PTC incidence was higher. This was true also for patients with secondary hyperparathyroidism. Conclusions This study emphasized that PHPT should be considered as a noteworthy risk factor for PTC. Fine needle aspiration of a thyroid nodule is the most valuable diagnostic procedure for thyroid cancer. Yet, false-negative results were reported in up to 10% of cases, especially in small, subcentimeter nodules. In line with our data and the literature, patients with PHPT should have both a detailed ultrasound addressing the thyroid and cytology of any thyroid nodule, including small subcentimeter lesions. Moreover, surgical flexibility, allowing intraoperative thyroid nodule sampling, should be considered even for "innocent" nodules.

Imaging-detected incidental thyroid nodules that undergo surgery: a single-center experience over 1 year

BACKGROUND AND PURPOSE

Incidental thyroid nodules are commonly seen on imaging, and their work-up can ultimately lead to surgery. We describe characteristics and pathology results of imaging-detected incidental thyroid nodules that underwent surgery.

MATERIALS AND METHODS

A retrospective review was performed of 303 patients who underwent thyroid surgery over a 1-year period to identify patients who presented with incidental thyroid nodules on imaging. Medical records were reviewed for the types of imaging studies that led to detection, nodule characteristics, and surgical pathology.

RESULTS

Of 303 patients, 208 patients (69%) had surgery for thyroid nodules. Forty-seven of 208 patients (23%) had incidental thyroid nodules detected on imaging. The most common technique leading to detection was CT (47%). All patients underwent biopsy before surgery. The cytology results were nondiagnostic (6%), benign (4%), atypia of undetermined significance or follicular neoplasm of undetermined significance (23%), follicular neoplasm or suspicious for follicular neoplasm (19%), suspicious for malignancy (17%), and diagnostic of malignancy (30%). Surgical pathology was benign in 24 of 47 (51%) cases of incidental thyroid nodules. In the 23 incidental cancers, the most common histologic type was papillary (87%), the mean size was 1.4 cm, and nodal metastases were present in 7 of 23 cases (30%). No incidental cancers on imaging had distant metastases.

CONCLUSIONS

Imaging-detected incidental thyroid nodules led to nearly one-fourth of surgeries for thyroid nodules, and almost half were initially detected on CT. Despite indeterminate or suspicious cytology results that lead to surgery, more than half were benign on final pathology. Guidelines for work-up of incidental thyroid nodules detected on CT could help reduce unnecessary investigations and surgery.

Impact of thyroid nodule size on prevalence and post-test probability of malignancy: a systematic review

OBJECTIVES/HYPOTHESIS

Large thyroid nodules may be associated with higher risk of malignancy and less-accurate fine-needle aspiration (FNA) results, but there is currently no overarching consensus. We therefore tested two null hypotheses: 1) thyroid nodule size >3 to 4 cm is not associated with a higher baseline prevalence of malignancy (i.e., the associated pretest probability is the same, regardless of size), and 2) thyroid nodule size >3 to 4 cm is not associated with worse diagnostic accuracy (i.e., the associated sensitivity, false-negative rate, and post-test probability of malignancy is not affected by nodule diameter).

STUDY DESIGN

Computerized searches of PubMed, Embase, and The Cochrane Library through July 2013 were performed, supplemented with manual searches.

METHODS

A priori criteria were defined to determine inclusion and exclusion of studies. Searches and data extraction were performed by independent reviewers and focused on FNA histopathologic findings and their relationship to nodule size, study design, and potential confounders.

RESULTS

Criterion-meeting studies (n = 15) included a total of 13,180 participants. The preponderance of prospective comparative studies showed a statistically significantly higher prevalence of malignancy in large nodules. Although data are mixed, evidence from the best-reported studies suggests sensitivity, false-negative rates, and frequency of true negatives among benign FNA results are worse in large nodules.

CONCLUSIONS

Large nodules have a higher pretest probability of malignancy. Data from larger studies suggest reduced FNA diagnostic accuracy in nodules >3 to 4 cm in diameter. Surgery represents a reasonable clinical option for nodules >3 cm.

Ultrasound-guided fine-needle aspiration of thyroid nodules: does size matter?

PURPOSE

Some authors have questioned the benefit of fine-needle aspiration (FNA) of thyroid nodules ≥ 4 cm. They report that the results of the FNA are not as reliable when compared to nodules <4 cm. The aims of this study are to evaluate the accuracy and predictive values of ultrasound-guided FNA (USFNA) of thyroid nodules ≥ 4 cm and compare these findings to nodules <4 cm.

METHODS

A retrospective study of 998 patients who underwent thyroid surgery between 2006 and 2012 at the McGill University Thyroid Cancer Center was performed. USFNA and post-operative pathology diagnoses of nodules ≥ 4 cm versus those <4 cm were compared. Pre-operative USFNA results were divided into three groups: benign, indeterminate, and malignant/suspicious for malignancy subgroups. Post-operative results were separated into benign and malignant groups.

RESULTS

There were 225 patients with nodules ≥ 4 cm and 773 patients with nodules <4 cm. The sensitivity, specificity, positive predictive value and negative predictive value for USFNA of nodules ≥ 4 cm were 84.62% (CI 71.91-93.10), 91.49% (CI 79.6-97.58), 91.67% (CI 80.0-97.63) and 84.31% (CI 71.4-92.95), respectively. The sensitivity, specificity, positive predictive value and negative predictive value for USFNA of nodules <4 cm were 90.48% (CI 86.1-93.8), 85.92% (CI 75.6-93.02), 95.8% (CI 92.41-97.96) and 71.76% (CI 60.95-81.0), respectively. The difference in diagnostic accuracy of USFNA between both groups was not statistically significant (p>0.05).

CONCLUSION

This study shows that the sensitivity, specificity, positive predictive value and negative predictive value for USFNA of nodules ≥ 4 cm are similar to that of smaller nodules. It is therefore suggested that these nodules undergo USFNA.

Thyroid nodules with benign findings at cytologic examination: results of long-term follow-up with US

PURPOSE

To investigate the natural history of thyroid nodules found to be benign at initial fine-needle aspiration biopsy (FNAB) to determine the percentage of nodules that increased in volume by more than 50% as being an indicator of malignancy.

MATERIALS AND METHODS

This retrospective observational cohort study was approved by the institutional review board, and the need to obtain informed consent was waived. The study included 854 FNAB-confirmed benign thyroid nodules. Suspicious ultrasonographic (US) features included marked hypoechogenicity, irregular or microlobulated margin, microcalcification, and taller-than-wide shape. Univariate and multivariate generalized linear mixed models were used to assess the association with nodule growth greater than 50% in volume.

RESULTS

For the 854 nodules, the initial mean diameter was 19.92 mm (range, 3.10-60.00 mm), and the initial mean volume was 3.19 cm(3) (range, 0.01-4.64 cm(3)). The majority (682 [79.9%] of 854) of thyroid nodules with benign cytologic results at initial FNAB did not grow more than 50% in volume during 4 years of mean follow-up (range, 7-101 months). More than 4 years of follow-up time versus less than 2 years, younger age, a cystic component of less than 25%, and nodule size 1 cm or larger versus less than 1 cm were independently associated with growth. There was only one malignant nodule (0.6%) among 172 thyroid nodules with a volume increase of 50% or greater during the entire follow-up time. Ten malignant nodules (overall malignancy rate: 1.2%) were detected among the 854 total nodules, and eight of these 10 nodules showed suspicious features at US.

CONCLUSION

Repeat FNAB for nodules showing more than 50% growth in volume is unlikely to result in a diagnosis of malignancy. A positive FNAB result for malignancy is significantly more likely in the presence of suspicious US features.

Molecular markers in the diagnosis of thyroid nodules

An indeterminate thyroid nodule cytology result occurs about every sixth fine-needle aspiration. These indeterminate nodules harbor a 24% risk of malignancy (ROM); too high to ignore, but driving surgery where most nodules are benign. Molecular diagnostics have emerged to ideally avoid surgery when appropriate, and to trigger the correct therapeutic surgery when indicated, as opposed to an incomplete diagnostic surgery. No current molecular test offers both high sensitivity and high specificity. A molecular diagnostic test with high sensitivity (e.g. Afirma Gene Expression Classifier sensitivity 90%) offers a high Negative Predictive Value when the ROM is relatively low, such as < 30%. Only such tests can "rule-out" cancer. In this setting, a molecularly benign result suggests the same ROM as that of operated cytologically benign nodules (~6%). Thus, clinical observation can replace diagnostic surgery; increasing quality of life and decreasing medical costs. However, its low specificity cannot "rule-in" cancer as a suspicious result has a Positive Predictive Value (PPV) of ~40%, perhaps too low to routinely reflex to definitive cancer surgery. Conversely, high specificity tests (BRAF, RAS, PPAR/PAX-8, RET/PTC, PTEN) offer high PPV results, and only these tests can "rule-in" cancer. Here a positive molecular result warrants definitive therapeutic surgery. However, their low sensitivity cannot "rule-out" cancer and a negative molecular result cannot dissuade diagnostic surgery; limiting their cost-effectiveness. Whether or not there is a useful and cost-effective role to sequentially combine these approaches, or to modify existing approaches, is under investigation.

Indeterminate pediatric thyroid fine needle aspirations: a study of 68 cases

OBJECTIVE

The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) provides a reporting scheme for thyroid fine needle aspiration (FNA) and includes three indeterminate categories with different management strategies. This study analyzes indeterminate thyroid FNAs in children, and correlates these findings with the histological features.

METHODS

A total of 179 thyroid FNA specimens were retrieved from children. Cases were categorized by TBSRTC. Only cases diagnosed as atypia (AUS)/follicular lesion of undetermined significance (FLUS), suspicious for follicular or oncocytic neoplasm (SFON), or suspicious for malignancy (SM) were selected and correlated with the nodule size and histological follow-up.

RESULTS

Sixty-eight cases were identified, including 43 (63%) AUS/FLUS diagnoses, 19 (28%) SFON, and 6 (9%) SM. On follow-up, 48% were malignant, including 28% AUS/FLUS cases, 58% SFON, and 100% SM. The average size of the malignant lesions diagnosed preoperatively as AUS/FLUS was 1.5 cm (range 0.7-4.5), compared to 3.3 cm (range 1.2-6.6) in SFON and 2.8 cm (range 0.7-3.8) in SM. Malignancies included 92% papillary thyroid carcinoma (PTC), 77% of which were the follicular variant of PTC (FVPTC) and 8% follicular carcinomas. The AUS/FLUS cases were largely due to compromised specimens (49%) and the highest malignancy rate occurred in those with cytological atypia (50%).

CONCLUSIONS

This study shows an incremental risk of malignancy within the indeterminate categories using TBSRTC in children. Malignant nodules with a preoperative AUS/FLUS diagnosis tended to be smaller than those with a SFON or SM diagnosis, and the vast majority of malignancies were PTC, with a high proportion being FVPTC.

The biopsy-proven benign thyroid nodule: is long-term follow-up necessary?

BACKGROUND

Thyroid nodules are common, and of those biopsied by fine-needle aspiration (FNA), the majority will be benign colloid nodules (BCN). Current guidelines suggest these BCN should be followed by ultrasonographic examination (US) every 3 years, with no endpoint specified. This study evaluated if long-term follow-up of benign thyroid nodules was associated with change in treatment or improvement in diagnosing a missed malignancy compared with short-term follow-up.

STUDY DESIGN

All patients with FNA-based diagnosis of BCN at our institution from 1998 to 2009 were identified. Patients observed after the diagnosis were divided into short-term follow-up (<3 years) and long-term follow-up (≥3 years). Rates of repeat FNA, thyroidectomy, and malignancy detection were compared.

RESULTS

Of 738 patients with BCN, 92 patients underwent thyroid resection after the initial US. Six hundred forty-six patients were observed, of which 366 returned for 1 or more follow-up US: 226 in the short-term group (median 13 months) and 140 in the long-term group (median 57 months). There were more follow-up US in long-term vs short-term (medians 4 vs 2, p < 0.01), more repeat FNAs in the long-term group (18 of 140 vs 8 of 226, p < 0.01); but no difference in interval thyroidectomies (13 of 140 vs 31 of 226, p = 0.25) or malignant final pathology (0 of 13 vs 2 of 31, p > 0.99). For all patients undergoing surgery, pathology was malignant in 2 of 136 (1.5%).

CONCLUSIONS

Long-term follow-up of patients with BCN is associated with increased repeat FNA and US without improvement in the malignancy detection rate. After 3 years of follow-up, consideration should be given to ceasing long-term routine follow-up of biopsy-proven BCN.