Reliability of fine-needle aspiration for thyroid nodules greater than or equal to 4 cm

Demographic, clinical, and surgical features of patients undergoing thyroidectomy due to thyroid lesions in Southern Iran: A cross-sectional study

Background and Aims

The incidence of thyroid cancer has witnessed a significant global increase and stands as one of the most prevalent cancers in Iran. This surge is primarily attributed to the escalating incidence of papillary thyroid cancer (PTC), with overdiagnosis emerging as an equally noteworthy factor. Consequently, this study aims to ascertain the incidence of thyroid cancer, along with its clinical presentation, demographic characteristics, and surgical features in patients undergoing thyroid surgery.

Methods

This cross-sectional study involved the evaluation of patient files from referral centers in Shiraz spanning the years 2015-2020. Demographic and clinical information pertaining to thyroid cancer was extracted and subsequently analyzed using SPSS software.

Results

A total of 533 documented cases of thyroid cancer undergoing surgery revealed an annual rate of 89 cases in our location. The average age of the patients was 43.9 ± 13.4 years (ranging from 13 to 92), with females constituting 429 (83.5%) of the cases, and 278 (54.1%) being malignant. Conventional PTC emerged as the most prevalent pathology, accounting for 239 (45.0%) of the cases. Patients with thyromegaly exhibited significantly higher incidences of nonmalignant tumors (p = 0.01), while those with malignant tumors were notably younger than those with nonmalignant tumors (p = 0.001).

Conclusion

Our study revealed a progressive rise in the number of patients undergoing thyroidectomy over the years, with PTC constituting the majority of cases. Malignant cases were more frequently observed in younger patients, and in smaller lesion sizes, highlighting the importance of early screening and optimizing detection methods, especially in high-risk populations.

Risk of malignancy and diagnostic accuracy of fine-needle aspiration biopsy in thyroid nodules with diameters greater than 4 centimeters

Objective

The risk of malignancy and diagnostic accuracy of fine-needle aspiration biopsy (FNAB) of thyroid nodules (TN) with diameters ≥ 3-4 cm remains controversial. However, some groups have indicated surgical treatment in these patients regardless of the FNAB results. We aimed to evaluate the diagnostic accuracy of the FNAB in systematically resected ≥4 cm TN and if the risk of malignancy is higher in these patients.

Subjects and methods

We retrospectively evaluated 138 patients (142 nodules) with TN with diameters ≥4 cm who underwent thyroidectomy.

Results

The FNAB results were nondiagnostic/unsatisfactory (ND/UNS) in 2.1% of the cases and benign in 51.4%. They indicated atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) in 23.9% of cases, follicular neoplasia/suspicious for a follicular neoplasm (FN/SFN) in 9.2%, suspicion of malignancy (SUS) in 8.5%, and malignant in 4.9%. The histopathological analysis after thyroidectomy revealed a thyroid cancer rate of 100% in the FNABs classified as malignant, 33.3% in SUS cases, 7.7% in FN/SFN, 17.6% in AUS/FLUS, and 4.1% in benign FNABs. None of the ND/UNS FNABs were malignant. The global malignancy diagnosis was 14.8% (n = 21). However, the rate of false negatives for FNAB was low (4.1%).

Conclusion

We showed that the risk of malignancy in nodules with diameters ≥4 cm was higher compared to the risk of thyroid cancer in TN in general. However, we found a low rate of false-negative cytological results; therefore, our data do not justify the orientation of routine resection for these larger nodules.

Accuracy of fine-needle aspiration cytopathology to differentiate malignant and benign thyroid nodules with ≥4 cm diameter: A retrospective study

BACKGROUND

Thyroid nodules (TN) are commonly present in the general population and are usually pathologically benign. An initial diagnosis with fine-needle aspiration (FNA) cytopathology could help clinical decision-making with fewer complications. As the previous studies suggest surgical procedures for >4 cm TNs, we aimed to investigate the accuracy of preoperative FNA cytology to predict malignancy risk in these nodules in a sample of the Iranian population.

METHODS

Patients with ≥4 cm TNs who had preoperative FNA cytology, underwent nodulectomy and had a histopathological report were included. Each patient's preoperative demographic, ultrasonographic, and cytology data were gathered. After surgery, resected samples were assessed pathologically and diagnosed as benign or malignant. Finally, data were analyzed to evaluate the presurgical accuracy of the FNA cytology.

RESULTS

We identified 41 (51.25%) patients with malignant legions among our study population (N = 80). The pathology reports were indeterminate in 3 patients with follicular neoplasm. Bethesda scores were substantially higher in patients with malignancy. The sensitivity, specificity, and false-negative rate of FNA cytology reports using the Bethesda system were 73.7%, 74.2%, and 26.3%, respectively. There was no association between malignancy and TNs' size, neither their volume nor their highest diameter.

CONCLUSION

FNA cytology is not as sensitive and specific in nodules>4 cm as in smaller ones. However, it can still be used alongside other diagnostic procedures in malignancy screening. Clinicians should make more complex decisions considering various influential factors to avoid missing malignant lesions and reduce diverse probable complications of highly invasive diagnostic surgery. Further prospective research on >4 cm TNs and their multiple features' association with malignancy is required for more precise judgment.

Large thyroid nodules: should size alone matter?

BACKGROUND

The management of thyroid nodules ≥ 4 cm is controversial due to conflicting evidence on the prevalence of malignancy and diagnostic accuracy of fine-needle aspiration cytology (FNAC). Some literature recommends routine excision of large thyroid nodules due to high cytology false negative rates (FNR). We aim to investigate the diagnostic accuracy of FNAC, prevalence of malignancy in large (≥ 4 cm) thyroid nodules compared to nodules < 4 cm, and the clinical and ultrasound characteristics of those large nodules with false negative cytology.

METHODS

This was a retrospective case-log review in a tertiary referral hospital. All thyroid nodules subjected to Ultrasound (US)-guided FNAC by the Interventional Radiology department between December 2011 and November 2017 were included. Data on patient demographics, thyroid US features, cytology findings, and surgical histology were collected and analyzed. Sensitivity, specificity, and FNR were calculated based on FNAC results and final post-operative histology. Factors associated with a false negative result were analyzed using univariate and multivariate analyses.

RESULTS

A total of 4982 nodules were studied, including 4419 < 4 cm and 563 ≥ 4 cm. Malignancy rates were similar in both groups. For nodules ≥ 4 cm, FNAC sensitivity was 40%, specificity 100%, and FNR 6.6% compared to 4.2% in nodules < 4 cm. Within malignant nodules, there was a significantly higher proportion of follicular and Hurthle cell carcinomas in nodules ≥ 4 cm. Amongst nodules ≥ 4 cm, multivariate analysis revealed male gender to be an independent predictor of FNR (OR 3.32; 95% CI 1.29-8.59).

CONCLUSION

Larger nodules ≥ 4 cm have a similar malignancy rate as nodules < 4 cm, and FNAC FNR is low at 6.6%. Management of large thyroid nodules should be individualized based on their clinical, sonographic and cytological features rather than routine surgery.

LEVEL OF EVIDENCE

3.

2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations

Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1-2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.

Current Evaluation of Thyroid Nodules

Thyroid nodules may be discovered in a variety of settings. Familiarity with their management is important for medical specialists. Workup should start with history and physical examination, proceed to laboratory studies, and then to imaging. Nodules are selected for fine needle aspiration (FNA) biopsy based on imaging criteria. Most nodules can be accurately diagnosed on cytopathology, but some may require additional molecular testing to evaluate risk of malignancy. Patients with malignant lesions require additional investigation before referral to an experienced thyroid surgeon. Those who have benign lesions may require monitoring by periodic ultrasound to identify nodules requiring reevaluation.

Ultrasound Parameters of Thyroid Nodules and the Risk of Malignancy: A Retrospective Analysis

Ultrasonography-guided fine-needle aspiration biopsy is the common choice for diagnosis of the suspected thyroid nodule. An algorithm(s) that finds the malignant potential of a nodule preoperatively, to overcome unnecessary diagnostic methods, does not exist. The objective of the study was to correlate thyroid nodule sizes measured by ultrasonography and risk of malignancy assessed by cytologic and histologic examinations. Data regarding fine-needle aspiration cytology and the results of histologic examinations of surgical specimens of 260 nodules were collected and analyzed. The macro or multiple calcifications, the complex echo pattern, and posterior region homogeneity were considered suspicious in ultrasonography. Bethesda system for classification of thyroid nodules was used for cytopathology. Histopathology performed as per the 2004 World Health Organization classification system. The benefit score analysis was performed for determination of clinical usefulness. Twenty-eight of 49 malignant nodules and 46 of 68 malignant nodules detected through ultrasound following fine-needle aspiration cytopathology and histopathology were <2 cm in size. A correlation was found for malignancy rate detected by ultrasonography-guided fine-needle aspiration cytology and those of the surgical specimen (r = 0.945, P = .015, R² = 0.894). Ultrasonography-guided fine-needle aspiration cytology had 0.994 sensitivities, 0.721 accuracies, and 0.08 to 0.945 diagnostic confidence for the detection of malignant nodules. Nodule size less than 2 mm (P = .011) was associated with the malignancy potential of thyroid nodules. Ultrasonography-guided fine-needle aspiration cytology had 19 (7%) results as a false negative and 1 (1%) results were false positive. Ultrasound-guided fine-needle aspiration cytopathology reported oversize of thyroid nodule than original but can predict the risk of malignancy. Level of Evidence: III.

False positive cases in thyroid cytopathology - the experience of a single laboratory and a systematic review

INTRODUCTION

Fine needle aspiration (FNA) is fundamental in the pre-operative assessment of thyroid nodules. However, the shining success of thyroid FNA is occasionally eclipsed by false positive (FP) cytological diagnoses. We describe our experience regarding FP cytological diagnoses and present a literature review concerning FP rates.

MATERIALS AND METHODS

We retrospectively analyzed 2031 consecutive cytology reports. FP was defined as a case with "suspicious for malignancy" or "malignant" cytology, whose surgical follow-up failed to confirm the initial diagnosis of malignancy. We used the PubMed database for the literature review using specific search terms ("thyroid", "cytology", "false positive").

RESULTS

Out of 2031 FNA reports, 93 cases with "suspicious for malignancy" or "malignant" cytology underwent surgical excision. Histopathology did not confirm malignancy in 10 cases (0.6% FP rate). Nodules with FP cytology were significantly larger (P = 0.0024) than those with with TP (true positive) cytology. A review of 25 publications shows comparable results to ours with some slight differences. The majority of studies achieve a FP rate below 3%. Most FP cytological diagnoses turn out to be non-neoplastic lesions (nodular hyperplasia, adenomatous nodule, lymphocytic thyroiditis), which combined account for 80.5% of all histological diagnoses.

CONCLUSIONS

Thyroid nodules with FP cytology were larger than nodules with TP cytology. Most studies manage to adhere to the recommended FP rates, or values close to them, with some outliers. Nevertheless, the mean FP rate values are very close to the value recommended by The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). The FP rate value depends on how one defines true negative cases, which can be either histologically proven benign cases, via a benign clinical course, or by assuming that cytologically benign cases remain as such.

The Risk of Thyroid Cancer in Patients with Thyroid Nodule 3 Cm Or Larger

OBJECTIVE

There are conflicting data on the risk of thyroid cancer in thyroid nodules 3 cm or larger, and few such studies on this issue have been conducted in Asia. This study aimed to examine the risk of thyroid cancer in patients with thyroid nodules 3 cm or larger.

METHODS

This was a 7-year retrospective study conducted in a tertiary referral hospital in Taiwan. All patients with a thyroid nodule measuring ≥3 cm who underwent thyroid operation with or without fine-needle aspiration biopsy (FNAB) were included. The prevalence rate of thyroid cancer, as well as the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and false-negative rate of FNAB for thyroid nodule ≥3 cm were also examined.

RESULTS

A total of 132 patients were included in this study. Thyroid cancer was detected in 19 of 132 (14.4%) thyroid nodules measuring ≥3 cm. The performance of FNAB for detecting cancer in nodules 3 cm or larger without considering other ultrasonography parameters was relatively poor with a sensitivity of 50%, but the specificity (100%), PPV (100 %), and NPV (93.4 %) were excellent.

CONCLUSION

The risk of thyroid cancer for thyroid nodules ≥3 cm in this study was low. The PPV and NPV of FNAB were high for the detection of cancer in large nodules. The decision to perform thyroidectomy should not be solely based on nodule size and should include other factors, such as ultrasound characteristics and surgical risk.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.

BACKGROUND

Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in the US.

METHODS

The medical literature from 1/1/1985 to 11/9/2018 was reviewed by a panel of 19 experts in thyroid disorders representing multiple disciplines. The authors used the best available evidence to construct surgical management recommendations. Levels of evidence were determined using the American College of Physicians grading system, and management recommendations were discussed to consensus. Members of the American Association of Endocrine Surgeons reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines analyze the indications for thyroidectomy as well as its definitions, technique, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Fine Needle Aspiration Biopsy Diagnosis, Molecular Testing, Indications, Extent and Outcomes of Surgery, Preoperative Care, Initial Thyroidectomy, Perioperative Tissue Diagnosis, Nodal Dissection, Concurrent Parathyroidectomy, Hyperthyroid Conditions, Goiter, Adjuncts and Approaches to Thyroidectomy, Laryngology, Familial Thyroid Cancer, Postoperative Care and Complications, Cancer Management, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal surgical management of thyroid disease.

The relationship of thyroid nodule size on malignancy risk according to histological type of thyroid cancer

Background

Although several studies have examined the value of thyroid nodule size as a malignancy predictor, the results are conflicting.

Purpose

To investigate the relationship between nodule size and malignancy risk and to evaluate the impact of nodule size on the false-negative rate of fine needle aspiration or core needle biopsy according to the histological type of thyroid cancer.

Material and Methods

From January 2013 to December 2013, 3970 thyroid nodules that underwent ultrasound-guided fine needle aspiration or core needle biopsy were retrospectively reviewed. We assessed the relationship between nodule size and malignancy risk according to histological type of thyroid cancer. In addition, we compared the false-negative rate by thyroid nodule size category.

Results

Of 3970 thyroid nodules, 1170 nodules were malignant. For papillary thyroid carcinoma, nodule size was inversely related to malignancy risk, whereas in nodules of follicular carcinoma and follicular variant papillary thyroid carcinoma, nodule size was positively related to malignancy risk ( P < 0.001). The false-negative rate tended to increase as nodule size increased ( P = 0.002) for all nodules and the overall false-negative rate was 2.3%.

Conclusion

Overall, nodule size does not correlate with risk of malignancy, but the relationship between nodule size and malignancy risk depends on the histological type of thyroid cancer.

Thyroid Nodule Size and Prediction of Cancer: A Study at Tertiary Care Hospital in Saudi Arabia

Background

Thyroid noduleshave become relatively common in clinical practice,and their prevalence increases with age. The majority of thyroid nodules are benign, with 5-15% being malignant. There are a number of well-established predictors of malignancy in thyroid nodules, but thyroid nodule size has been a cause for concern for many researchers and results of the studies are still controversial about their probability of malignancy. Up to the current knowledge, there is no published study that evaluates if thyroid nodule size is associated with the risk of malignancy in Saudi Arabia, so in this study, we aim to find that.

Methods

This is a retrospective study of 987 patients who underwent thyroid nodule fine-needle aspiration (FNA) and subsequent thyroidectomy for thyroid nodules measuring ≥ 1 cm.

Results

Thyroid cancer was more prevalent in males than females, and in patients who were older than or equal to 45 years. Nodular size of 1 - 1.9 cm was more prevalent among cancer patients than in benign cases (p<0.001).

Conclusions

The highest malignancy risk was observed in nodules <2 cm and no increase in malignancy risk for nodules >2 cm. Nevertheless, when examined by type of thyroid malignancy, the rate of follicular carcinoma and other rare malignancy increased with increasing nodule size.

Association between thyroid nodule size and malignancy rate

INTRODUCTION

The diagnostic performance of ultrasound-fine needle aspiration to identify thyroid nodules harbouring malignancy remains variable. The aim of this study was to determine thyroid nodule size and cytological classification as predictors of malignancy risk.

MATERIALS AND METHODS

We conducted a retrospective cohort analysis at an academic hospital involving 499 consecutive patients who underwent thyroid surgery between 2004 and 2015.

RESULTS

A total of 503 thyroid nodules (499 patients, 84% female; mean age 50.8 years, standard deviation, SD, 15.4 years) were analysed. Of these, 19.5% were malignant. The mean (± SD) nodule size was 3.28 ± 1.63 cm and 3.27 ± 1.54 cm for benign and malignant nodules, respectively. The odds of malignancy for thyroid nodules less than 3.0 cm was similar to those for nodules of 3.0 cm or greater (0.26 compared with 0.29; p=0.77). Overall, the sensitivity and specificity of fine-needle aspiration in this cohort were 71.4% and 100%, respectively. The overall false negative rate was 5.4%. When the cut-off of 3.0 cm was used, the false negative rate in thyroid nodules less than 3.0 cm was 0% compared with 7.0% in nodules of 3.0 cm or greater. Thus, class (p<0.01) but not nodule size (p=0.49), was associated with higher malignancy risk.

CONCLUSIONS

Our results suggest that thyroid nodule size did not accurately predict the risk of thyroid malignancy irrespective of fine-needle aspiration cytology. Routine diagnostic thyroid lobectomy solely owing to thyroid nodule size of 3.0 cm or greater is currently not justified.

Clinical and Ultrasound Thyroid Nodule Characteristics and Their Association with Cytological and Histopathological Outcomes: A Retrospective Multicenter Study in High-Resolution Thyroid Nodule Clinics

INTRODUCTION

Thyroid nodules are a common finding. A high-resolution thyroid nodule clinic (HR-TNC) condenses all tests required for the evaluation of thyroid nodules into a single appointment. We aimed to evaluate the clinical outcomes at HR-TNCs.

DESIGN AND METHODS

A retrospective cross-sectional multicenter study including data from four HR-TNCs in Spain. We evaluated fine-needle aspiration (FNA) indications and the association between clinical and ultrasound characteristics with cytological and histopathological outcomes.

RESULTS

A total of 2809 thyroid nodules were included; FNA was performed in 82.1%. Thyroid nodules that underwent FNA were more likely larger, isoechoic, with microcalcifications, and in younger subjects. The rate of nondiagnostic FNA was 4.3%. A solid component, irregular margins or microcalcifications, significantly increased the odds of Bethesda IV-V-VI (vs. Bethesda II). Irregular margins and a solid component were independently associated with increased odds of malignancy. Thyroid nodules <20 mm and ≥20-<40 mm had a 6.5-fold and 3.3-fold increased risk for malignancy respectively in comparison with those ≥40 mm.

CONCLUSION

In this large multicenter study, we found that the presence of a solid component and irregular margins are factors independently related to malignancy in thyroid nodules. Since nodule size ≥40 mm was associated with the lowest odds of malignancy, this cut-off should not be a factor leading to indicate thyroid surgery. HR-TNCs were associated with a low rate of nondiagnostic FNA.

Computed tomography versus ultrasound/fine needle aspiration biopsy in differential diagnosis of thyroid nodules: a retrospective analysis

Introduction

Ultrasound sonography provides a quick method for determining which nodule to sample for fine needle aspiration biopsy in thyroid nodules. On the other hand, the computed tomography examination is not restricted by echo attenuation and distinguishes between benign and malignant nodules.

Objective

To compare computed tomography examinations against ultrasound/fine needle aspiration biopsy in the differential diagnosis of thyroid nodules.

Methods

Data regarding computed tomography examinations, sonographic finding following fine needle aspiration biopsy, and tumor histology of 953 nodules from 698 patients who underwent thyroidectomy were collected and analyzed. The beneficial score for detection of the malignant tumor for each adopted modality was evaluated.

Results

Ultrasound images did not show a well-circumscribed solid mass in 89 nodules, and ultimately did not detect nodules in fine needle aspiration biopsies (false positive non-malignant nodules). Ultrasound images showed parenchymatous disease (false positive malignant nodules) in several nodules. Computed tomography examinations demonstrated higher difficulty in detection of malignant nodules of 1.0–2.0 cm size than ultrasound examination following fine needle aspiration biopsies; compared to tumor histological data, computed tomography examinations had a sensitivity of 0.879.

Conclusion

Computed tomography examinations are a more reliable method for differential diagnosis of thyroid nodules than ultrasound examinations followed by fine needle aspiration biopsy.

Level of Evidence

III.

Thyroid nodules over 4 cm do not have higher malignancy or benign cytology false-negative rates

PURPOSE

Whether thyroid nodules 4 cm or larger with benign cytology carry a higher risk of malignancy, and should be managed differently than smaller nodules remains controversial. We aimed to evaluate the malignancy rate and benign cytology false-negative rate in thyroid nodules ≥4 cm compared with those <4 cm.

METHODS

All thyroidectomies between January 2010 and December 2014 were reviewed. Patient demographics, preoperative sonographic nodule size, fine needle aspiration cytology (FNAC), and final surgical pathology results were compared for index nodules ≥4 vs. <4 cm.

RESULTS

A total of 490 index nodules with preoperative FNAC were identified. A total of 137 nodules were ≥4 cm and 353 nodules were <4 cm. The prevalence of carcinoma was lower (23 vs. 53%) in nodules ≥4 vs. <4 cm (p < 0.0001). The false-negative rate of benign FNAC for ≥4 and <4 cm index nodule was 5.2% and 5.9%, respectively (p = 1.000).

CONCLUSIONS

This study shows that thyroid nodules ≥4 cm do not have a higher malignancy rate at surgery nor higher benign cytology false-negative rate than smaller nodules. Thyroid nodules over 4 cm do not require resection, to rule out malignancy, based on size alone.

Treatment of solitary thyroid nodules according to size, preoperative fine-needle aspiration cytology and frozen section: a retrospective single centre study

Background: In order to avoid unnecessary thyroidectomies, it is important to predict the nature of thyroid nodules the more accurately possible. The size of the nodule as a predictive factor for malignancy is very controversial. Another point of debate is the accuracy of preoperative fine-needle aspiration cytology (FNAC) and frozen section (FS). The aim of our study is to correlate the nodule size with the final histological diagnosis and to estimate the accuracy of preoperative FNAC and FS. Methods: Retrospective study including 387 operated patients with ultrasound-detected solitary thyroid nodules from 01 January 2001 to 31 December 2013. The following data were collected: patient age and sex, nodule size, FNAC, FS and final histology results. Results: The odds ratio for malignancy within nodules <40 mm was 2.12 (95% CI: 1.104-4.084). The specificity of FNAC was 97.78% and the negative predictive value (NPV) was 97.78% for nodules ≥40 mm and 93.2% and 96.5% for nodules <40 mm, respectively. The observed specificity and NPV of FS ranged from 98% to 100% and from 87.4% to 98%, respectively. When combining FNAC and FS, the specificity and the NPV were 99% and 98%, respectively. Conclusions: The nodule size is not a predictive factor for thyroid cancer and therefore nodules ≥40 mm should not be routinely resected. A lege artis preparation and performance of FNAC along with an expertise on cytological interpretation can considerably diminish false-negative rate. FS can offer additional accuracy on FNAC results and should, therefore, be a part of patient treatment.

Ultrasound-guided needle biopsy of large thyroid nodules: Core needle biopsy yields more reliable results than fine needle aspiration

PURPOSE

The objective of this study was to compare the false negative rate, sensitivity and false positive rate of ultrasound (US)-guided fine needle aspiration (FNA) with those of US-guided core needle biopsy (CNB) for large thyroid nodules ≥2.0 cm, which reportedly have an increased risk of thyroid malignancy.

METHODS

We retrospectively studied surgically confirmed thyroid nodules that had preoperative US-guided FNA or CNB between March 2005 and December 2013. We reviewed nodule size, sonographic features, cytohistologic results, and final surgical pathology. We assessed false negative rates, sensitivity, and false positive rates by biopsy method and nodule size for diagnosis of thyroid malignancy. We assessed complications for procedures.

RESULTS

US-guided CNB showed better diagnostic performance, in terms of lower false negative rates and greater sensitivity, than US-guided FNA in large thyroid nodules. There was no significant difference in false positive rate according to biopsy methods in large thyroid nodules. The false negative rates of large thyroid nodules (≥2.0 cm) were higher than those of small nodules (<2.0 cm). There were no major complications, and no significant differences in complication according to biopsy methods.

CONCLUSION

US-guided CNB improved the false negative rate and sensitivity for large nodules. Therefore, US-guided CNB can be considered a useful diagnostic method for large thyroid nodules that might reduce the risk of unnecessary diagnostic surgery.

Is thyroid nodule volume predictive for malignancy?

OBJECTIVE

We aimed to determine the roles of preoperative thyroid nodule diameter and volume in the prediction of malignancy.

SUBJECTS AND METHODS

The medical records of patients who underwent thyroidectomy between January 2007 and December 2014 were reviewed. The nodule diameters were grouped as < 1 cm, 1-1.9 cm, 2-3.9 cm and ≥ 4 cm, and volume was grouped as > 5 cm3, 5-9.9 cm3 and > 10 cm3. ROC (Receiver Operating Characteristic) curve analysis was performed to find the optimal cutoff value of diameter and volume that can predict malignancy.

RESULTS

There were 5561 thyroid nodules in 2463 patients. Five hundred and forty (9.7%) nodules were < 1 cm, 2,413 (43.4%) were 1-1.9 cm, 1,600 (28.8%) were 2-3.9 cm and 1,008 (18.1%) were ≥ 4 cm. Malignancy rates were 25.6%,10.6%, 9.7% and 8.5% in nodules < 1 cm, 1-1.9 cm, 2-3.9 cm and ≥ 4 cm, respectively. When classified according to volume, 3,664 (65.9%) nodules were < 5 cm3, 594 (10.7%) were 5-9.9 cm3 and 1,303 (23.4%) were ≥ 10 cm3. The malignancy rates were 12.7%, 11.4% and 7.8% for the nodules < 5 cm3, 5-9.9 cm3 and ≥ 10 cm3, respectively (p < 0.001). In ROC curve analysis, an optimal cutoff value for diameter or volume that can predict malignancy in all thyroid nodules or nodules ≥ 4 cm could not be determined.

CONCLUSION

In this surgical series, malignancy risk did not increase with increasing nodule diameter or volume. Although the volume of malignant nodules ≥ 4 cm was higher than that of benign nodules ≥ 4 cm, there was no optimal cutoff value. The diameter or volume of the nodule cannot be used to predict malignancy or decide on surgical resection.

The influence of thyroid nodule size on the diagnostic efficacy and accuracy of ultrasound guided fine-needle aspiration cytology

BACKGROUND

Diagnostic accuracy of fine-needle aspiration cytology (FNAC) in large and subcentimeter nodules is still debated. We aimed to evaluate the impact of nodule size on efficacy of the ultrasound-guided FNAC.

METHODS

B-mode grayscale ultrasound (US), US-guided FNAC according to Bethesda system and histopathological data of 514 nodules from 371 patients, who underwent thyroidectomy were examined retrospectively. Nodules were grouped by maximal diameter; group A nodules were smaller than 10 mm (n = 59), group B nodules were between 10 and 29 mm (n = 218), and group C nodules were 30 mm or greater (n = 130).

RESULTS

Sensitivity, specificity, and accuracy of FNAC was 92.0%, 100%, and 95.1% in group A, 80.7%, 99.1%, and %92.9 in group B, 70.0%, 98.9%, and 95.8% in group C nodules, respectively. The prevalence of papillary thyroid cancer (PTC) and incidental PTC were 44.2% (n = 164) and 6.4% (n = 24), respectively. Malignancy rate was more frequent in group A when compared to groups B and C (P < 0.01). Nodule size was positively associated with follicular cancer risk (P = 0.009). The thyroid stimulating hormone level was positively associated with malignancy (P = 0.02) and optimal cut-off value was 0.96 mIU/L. False-negative rate was 8.0%, 19.3%, and 30.0% in groups A, B, and C nodules, respectively.

CONCLUSIONS

Although the malignancy rate was low in nodules ≥30 mm, diagnostic surgery for large nodules should be considered because of decreased reliability of FNAC, ineffectiveness of clinical and sonographic criteria. False-negative rate was relatively low and malignancy rate was high in subcentimeter nodules, supporting the accuracy of FNAC.

Malignancy risk for thyroid nodules larger than 4 cm and diagnostic reliability of ultrasound-guided FNAB results

Objectives

Our aim in the present study was to investigate the relation between thyroid nodule diameter and malignancy, and the diagnostic accuracy of fine needle aspiration biopsy (FNAB) for thyroid nodules larger than 4 cm.

Material and Methods

Preoperative patient demographics such as age and gender, thyroid nodule diameter, FNAB results and postoperative pathology results were recorded. The relation between age, gender, thyroid nodule size of the patients and malignancy was examined. Also, the sensitivity, specificity, false negativity, false positivity and accuracy rates of FNBA of the patients whose thyroid nodule size was lower than 4 cm and the ones whose thyroid nodule size was higher than 4 cm were analyzed.

Results

There was no significant difference between males and females in terms of malignancy rate (p= 0.15). There was no significant relation between malignancy and patient age (p= 0.92). No significant difference was found between the group with thyroid nodule diameter of > 4 cm and the group thyroid with nodule diameter of <4 cm in terms of malignancy (p= 0.91). In the group with thyroid nodule diameter of > 4 cm, sensitivity, specificity, false negativity, false positivity, and accuracy rates of FNAB were 15%, 100%, 84%, 0%, and 70%, respectively. In the group with thyroid nodule diameter of <4 cm, sensitivity, specificity, false negativity, false positivity, and accuracy rates of FNAB were 53%, 100%, 46%, 0% and 80%, respectively.

Conclusion

Our study put forward that thyroid nodule diameter is not the only predictor parameter whilst predicting malignancy. However, it was observed that FNAB sensitivity and false negativity were higher when the thyroid nodules with > 4 cm diameter were compared to the thyroid nodules with <4 cm diameter.

Large Cytologically Benign Thyroid Nodules Do Not Have High Rates of Malignancy or False-Negative Rates and Clinical Observation Should be Considered: A Meta-Analysis

Background: Management of large thyroid nodules is controversial, as data are conflicting regarding overall rates of malignancy (ROM) in all nodules and frequency of false-negative fine-needle aspiration results (FNR) in cytologically benign nodules. This meta-analysis aimed to evaluate and compare ROM and FNR in small versus large nodules published in the literature. Methods: Articles indexed in PubMed, written in English, published electronically or in print on or prior to December 8 2017 were searched for "false negative thyroid size or cm" and "malignancy rates benign thyroid nodules." Three hundred fifty-two unique citations were identified. Multiple reviewers selected a final set of 35 articles that contained nodules stratified by size (3, 4, or 5 cm), with benign or all cytologic diagnoses, and with postsurgical histologic diagnoses. Multiple observers extracted data, including numbers of total, cytologically benign, and histologically malignant nodules. Size cutoffs of 3, 4, and/or 5 cm were analyzed in 14, 24, and 1 article, respectively. Results: ROM in all nodules ≥3 cm (13.1%) and ≥4 cm (20.9%) was lower than those <3 cm (19.6%) and <4 cm (19.9%; odds ratio [OR] = 0.72 [confidence interval (CI) 0.64-0.81] and OR = 0.85 [CI 0.77-0.95]). FNR in nodules ≥3 cm (7.2%) was not different from smaller nodules (5.7%; OR = 1.47 [CI 0.80-2.69]). FNR in nodules ≥4 cm (6.7%) was slightly higher than those <4 cm (4.5%; OR = 1.38 [CI 1.06-1.80]). The most frequently reported false-negative diagnosis was papillary thyroid carcinoma. Conclusions: Rates of malignancy and false-negative FNA results vary but, in most studies, are not higher in larger nodules. Patients with large, cytologically benign thyroid nodules need not undergo immediate surgical resection, as false-negative FNA rates are low and are expected to decrease in light of nomenclature revision of a subset of follicular variants of papillary thyroid carcinoma.

Controversy regarding when clinically suspicious thyroid nodules should be subjected to surgery: Review of current guidelines

BACKGROUND

The work-up of a thyroid nodule to diagnose malignancy is not always straightforward. There are various international thyroid societies each with their own guidelines on the approach to a thyroid nodule. The aim is therefore to determine whether a clinically suspicious thyroid nodule should be subjected to surgery.

METHOD

A review of various international thyroid society guidelines on their approach to a suspicious thyroid nodule.

RESULTS

Sixty-two relevant articles were identified of which 4 current international thyroid guidelines, consisting of 6 different international societies, were reviewed. The commonalities of each of the thyroid society guidelines are imaging, with ultrasound, and cytopathology as the main diagnostic investigations. The description and the size of the nodule are the 2 most important factors on ultrasound; however, the guidelines vary in their recommendations whether to biopsy a suspicious thyroid nodule. An indeterminate group exists whereby thyroid nodules cannot be confirmed as malignant even with fine needle aspiration cytology (FNA). Although further investigations (Technetium-99m -sestamethoxyisobutylisonitryl scan, 18F-fluorodeoxyglucose positron emission tomography/computed tomography scan, and molecular testing) may assist in the diagnosis, there are limitations. There are differences in the guidelines whether suspicious nodules should be subjected to surgery.

CONCLUSION

Ultrasound and cytopathology are the 2 most appropriate investigations to diagnose whether a suspicious thyroid nodule is benign or malignant. The clinician needs to be aware of the differences between the guidelines from the various international thyroid societies, specifically concerning the indeterminate group of patients where a definitive diagnosis cannot be made. Management decisions should be discussed with a thyroid multidisciplinary team for a consensus decision whether or not to subject a patient with a suspicious thyroid nodule to surgery.

Thyroid nodule size calculated using ultrasound and gross pathology as predictors of cancer: A 23-year retrospective study

BACKGROUND

Thyroid nodules are very common. Ultrasound (US) and fine needle aspiration (FNA) are both integral in cancer screening. This study investigated the concordance between thyroid nodule sizes measured by US and gross pathologic examination and their relationship with malignancy.

METHODS

A retrospective design was used to select consecutive patients with proven carcinoma of the thyroid. The number and maximum diameter of nodules, rates and types of malignancy, as well as predictors of malignancy were determined.

RESULTS

The 10 944 patients examined had 15 283 thyroid nodules, 44.6% of which were malignant. Of the 4449 nodules sampled by FNA and the 8748 not sampled by FNA, 76.5% and 30.5% were malignant, respectively. The sensitivity, specificity, positive and negative predictive values (NPVs), and overall accuracy of FNA based on final pathology were 97.9%, 96.3%, 98.8%, 93.5%, and 97.5%, respectively. Nodule sizes determined by US were comparable with most nodules having either the same size range (n = 2959, 77.7%) or differing only by one size range (n = 770, 20.5%).

CONCLUSIONS

Thyroid nodule size is inversely related to malignancy risk, as larger nodules have lower malignancy rates. Nodule size estimated by US shows relatively good correlation with final pathologic size. However, thyroid nodules should undergo FNA regardless of size. If the FNA is not benign, nodule size should influence therapeutic decision making.

Utility of Intraoperative Frozen Section in Large Thyroid Nodules

OBJECTIVE

To determine if the routine use of intraoperative frozen section (iFS) results in cost savings among patients with nodules >4 cm with nonmalignant cytology undergoing a thyroid lobectomy.

STUDY DESIGN

Case series with chart review; cost minimization analysis.

SETTING

Single academic center.

SUBJECTS AND METHODS

Records were reviewed on a consecutive sample of 48 patients with thyroid nodules >4 cm and nonmalignant cytology who were undergoing thyroid lobectomy in which iFS was performed between 2010 and 2015. A decision tree model of thyroid lobectomy with iFS was created. Comparative parameters were obtained from the literature. A cost minimization analysis was performed comparing lobectomy with and without iFS and the need for completion thyroidectomy with costs estimated according to 2014 data from Medicare, the Bureau of Labor Statistics, and the Nationwide Inpatient Sample.

RESULTS

The overall malignancy rate was 25%, and 33% of these malignancies were identified intraoperatively. When the malignancy rates obtained from our cohort were applied, performing routine iFS was the less costly scenario, resulting in a savings of $486 per case. When the rate of malignancy identified on iFS was adjusted, obtaining iFS remained the less costly scenario as long as the rate of malignancies identified on iFS exceeded 12%. If patients with follicular lesions on cytology were excluded, 50% of malignancies were identified intraoperatively, resulting in a savings of $768 per case.

CONCLUSIONS

For patients with nodules >4 cm who are undergoing a diagnostic lobectomy, the routine use of iFS may result in decreased health care utilization. Additional cost savings could be obtained if iFS is avoided among patients with follicular lesions.

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.

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.

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.

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.

Reliability of fine needle aspiration biopsy in large thyroid nodules

OBJECTIVE

Fine needle aspiration biopsy provides one of the most important data that determines the treatment algorithm of thyroid nodules. Nevertheless, the reliability of fine needle aspiration biopsy is controversial in large nodules. The aim of this study was to evaluate the adequacy of fine needle aspiration biopsy in thyroid nodules that are four cm or greater.

MATERIAL AND METHODS

We retrospectively examined 219 patients files who underwent thyroidectomy for thyroid nodules that were greater than four centimeter between May 2007 and December 2012. Seventy-four patients with hyperthyroidism, and 18 patients without preoperative fine needle aspiration cytology were excluded from the study. Histopathologic results after thyroidectomy were compared with preoperative cytology results, and sensitivity and specificity rates were calculated.

RESULTS

False-negativity, sensitivity and specificity rates of fine needle aspiration biopsy of thyroid nodules were found to be 9.7%, 55.5%, and 85%, respectively. Within any nodule of the 127 patients, 28 (22.0%) had thyroid cancer. However, when only nodules of at least 4 cm were evaluated, thyroid cancer was detected in 22 (17.3%) patients.

CONCLUSION

In this study, fine needle aspiration biopsy of large thyroid nodules was found to have a high false-negativity rate. The limitations of fine-needle aspiration biopsy should be taken into consideration in treatment planning of thyroid nodules larger than four centimeters.

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.

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.

Cost-Effectiveness of Diagnostic Lobectomy Versus Observation for Thyroid Nodules >4 cm

BACKGROUND

The management of thyroid nodules >4 cm with benign cytology after fine-needle aspiration biopsy (FNAB) is controversial. FNAB is associated with a high false-negative rate in this setting, and may result in a delayed diagnosis and management of thyroid cancer. However, the majority of these nodules are benign. Therefore, the objective of this study was to determine the cost-utility of observation versus surgical management for thyroid nodules >4 cm with benign cytology after FNAB.

METHODS

A microsimulation model comparing routine thyroid lobectomy with observation for low-risk patients with >4 cm thyroid nodules with benign FNAB cytology was constructed. Costs, quality-adjusted life-years (QALYs), and life-years gained were calculated over a lifetime time horizon from a U.S. Medicare perspective.

RESULTS

The proportion of patients undergoing thyroid lobectomy for benign final pathology was 40% in the observation strategy versus 66% in the surgical strategy (p < 0.001). Overall, the surgical strategy was associated with higher lifetime costs compared with the observation strategy (incremental difference: + US$12,992 [confidence interval (CI) 13,042-13,524]), but also more QALYs (+0.12 QALYs [CI 0.02-0.24]) and longer life expectancy (+1.67 years [CI 1.00-2.41]). Incremental lifetime costs were lower for patients <55 years compared with those ≥55 years (+11,181 vs. +14,811, p < 0.001). The probability of cost-effectiveness of the surgical strategy was 49% at a $100k/QALY threshold or 65% at a $100k/life-year gained threshold.

CONCLUSIONS

Routine thyroid lobectomy is associated with improved outcomes at an acceptable cost compared with observation for thyroid nodules >4 cm with benign cytology after FNAB. Surgical resection may be a cost-effective strategy to rule out malignancy in these nodules.

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.

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.

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.