Predictive index for carcinoma of thyroid nodules and its integration with fine-needle aspiration cytology

Diagnostic Accuracy of Fine-Needle Biopsy in the Detection of Thyroid Malignancy: A Systematic Review and Meta-analysis

Importance

Fine-needle biopsy (FNB) became a critical part of thyroid nodule evaluation in the 1970s. It is not clear how diagnostic accuracy of FNB has changed over time.

Objective

To conduct a systematic review and meta-analysis estimating the accuracy of thyroid FNB for diagnosis of malignancy in adults with a newly diagnosed thyroid nodule and to characterize changes in accuracy over time.

Data Sources

PubMed, SCOPUS, and Cochrane Central Register of Controlled Trials were searched from 1975 to 2020 using search terms related to FNB accuracy in the thyroid.

Study Selection

English-language reports of cohort studies or randomized trials of adult patients undergoing thyroid FNB with sample size of 20 or greater and using a reference standard of surgical histopathology or clinical follow-up were included. Articles that examined only patients with known thyroid disease or focused on accuracy of novel adjuncts, such as molecular tests, were excluded. Two investigators screened each article and resolved conflicts by consensus. A total of 36 of 1023 studies met selection criteria.

Data Extraction and Synthesis

The MOOSE guidelines were used for data abstraction and assessing data quality and validity. Two investigators abstracted data using a standard form. Studies were grouped into epochs by median data collection year (1975 to 1990, 1990 to 2000, 2000 to 2010, and 2010 to 2020). Data were pooled using a bivariate mixed-effects model.

Main Outcomes and Measures

The primary outcome was accuracy of FNB for diagnosis of malignancy. Accuracy was hypothesized to increase in later time periods, a hypothesis formulated prior to data collection.

Results

Of 16 597 included patients, 12 974 (79.2%) were female, and the mean (SD) age was 47.3 (12.9) years. The sensitivity of FNB was 85.6% (95% CI, 79.9-89.5), the specificity was 71.4% (95% CI, 61.1-79.8), the positive likelihood ratio was 3.0 (95% CI, 2.3-4.1), and the negative likelihood ratio was 0.2 (95% CI, 0.2-0.3). The area under the receiver operating characteristic curve was 86.1%. Epoch was not significantly associated with accuracy. None of the available covariates could explain observed heterogeneity.

Conclusions and Relevance

Accuracy of thyroid FNB has not significantly changed over time. Important developments in technique, preparation, and interpretation may have occurred too heterogeneously to capture a consistent uptrend over time. FNB remains a reliable test for thyroid cancer diagnosis.

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.

A Scoring System for Assessing the Risk of Malignant Partially Cystic Thyroid Nodules Based on Ultrasound Features

Objective

To assess the ultrasound (US) features of partially cystic thyroid nodules (PCTNs) and to establish a scoring system to further improve the diagnostic accuracy.

Methods

A total of 262 consecutive nodules from September 2017 to March 2020 were included in a primary cohort to construct a scoring system. Moreover, 83 consecutive nodules were enrolled as an validation cohort from May 2018 to August 2020. All nodules were determined to be benign or malignant according to the pathological results after surgery or ultrasound-guided fine-needle aspiration (US-FNA). The US images and demographic characteristics of the patients were analyzed. The ultrasound features of PCTNs were extracted from primary cohort by two experienced radiologists. The features extracted were used to develop a scoring system using logistic regression analysis. Receiver operating characteristic (ROC) curves were applied to evaluate the diagnostic efficacy of the scoring system in both the primary cohort and validation cohort. In addition, the radiologists evaluated the benign and malignant PCTNs of the validation cohort according to the ACR TI-RADS guidelines and clinical experience, and the accuracy of their diagnosis were compared with that of the scoring system.

Results

Based on the eight features of PCTNs, the scoring system showed good differentiation and reproducibility in both cohorts. The scoring system was based on eight features of PCTNs and showed good performance. The area under the curve (AUC) was 0.876 (95% CI, 0.830 - 0.913) in the primary cohort and 0.829(95% CI, 0.730 - 0.903) in the validation cohort. The optimal cutoff value of the scoring system for the diagnosis of malignant PCTNs was 4 points, with a good sensitivity of 71.05% and specificity of 87.63%. The scoring system (AUC=0.829) was superior to radiologists (AUC= 0.736) in diagnosing PCTNs and is a promising method for clinical application.

Conclusions

The scoring system described herein is a convenient and clinically valuable method that can diagnose PCTNs with relatively high accuracy. The use of this method to diagnose PCTNs, which have been previously underestimated, will allow PCTNs to receive reasonable attention, and assist radiologist to confidently diagnose the benignity or malignancy.

Clinical profile and management of primary thyroid cancer in patients with nodular goitre at the Douala General Hospital, Cameroon

Introduction

thyroid cancer (TC) is considered to have become the fastest growing cancer in terms of incidence worldwide. Despite literature reporting a prevalence of 5-10% in clinically identified thyroid nodules, Cameroon still has limited data on the profile of TCs in patients with Nodular Goitres (NGs). The Objective were to describe the epidemiological, diagnostic and therapeutic profiles of TCs in patients with nodular goitres at the Douala General Hospital (DGH).

Methods

this was a retrospective cross-sectional analysis of patient records with diagnoses of NGs, over 11 years (2006 to 2016) at the DGH.

Results

overall, 187 patients (mean age= 46.8±13.9 years, men=27 (14.4%)) were included; 43 (23%) cancers were identified. The most common histological type was papillary cancer (50%). Nodule size of >4cm and hypoechogenicity were independently associated with malignancy. Most patients presented with TNM stage II (47.4%) and well-differentiated cancers were considered to be predominantly at low-risk according to MACIS (55%) and AMES (74%) scores. Surgery was offered to 95.3% of patients.

Conclusion

TCs are frequent in patients with NGs with papillary cancer dominating. A high index of suspicion should be held if a nodule is >4cm and/or is hypoechogenic. Prognostic studies are needed to describe the outcome of TCs in our setting.

A Prospective Observational Study Assessing the Relationship Between Solitary Thyroid Nodule Size and Incidence of Malignancy

Background

Solitary thyroid nodule (STN) is a well-documented entity. Autopsy data indicate a 50% prevalence of thyroid nodules >10 mm in patients without clinical evidence of thyroid disease. Prevalence of palpable nodules is 4-7%. Solitary thyroid nodules are often asymptomatic and found incidentally. Fine needle aspiration cytology is recommended to determine the nature of the thyroid nodule. 5-10% of the thyroid nodules are found to be malignant following thyroidectomy.

Objective

Our study aims to explore the relationship between solitary thyroid nodule size and malignancy.

Methods

A prospective, observational analysis looking at preoperative thyroid ultrasound scan findings and post-operative histology for a total of 100 female patients referred to our unit within a university hospital from November 2016 to April 2019. Statistical analysis including One-Way ANOVA was performed where appropriate.

Results

Total number of patients was 100 female patients divided according to the size of the nodule into three groups with the correlation between the size of the nodule and the incidence of malignancy.

Group A: Patients with a STN <20 mm; eight patients; post-operative histology = all benign.

Group B: Patients with a STN measuring 20-40 mm; 80 patients: 68 patients were benign, and 12 patients (12%) were malignant (incidence of malignancy in the group is 15%).

Group C: Patients with a STN >40 mm; 12 patients: eight patients were benign, four patients were malignant, (incidence of malignancy = 33%).

Correlation between the size of the nodule and the incidence of malignancy:

Group A: 0/8 malignancy; Group B: 12/80 patients were malignant; Group C: 4/12 malignant.

Conclusion

Our results suggest that the size of a solitary thyroid nodule cannot be reliably used for at predicting malignancy and should not be influencing patient’s management.

Malignancy Analyses of Thyroid Nodules in Patients Subjected to Surgery with Cytological- and Ultrasound-Based Risk Stratification Systems

The fine needle aspiration (FNA) cytology is the gold standard for the preoperative diagnosis of thyroid cancer. However, up to 30% of FNA examinations yield nondiagnostic or indeterminate results and this complicates patient management. Clinical features and ultrasound (US) patterns, including US risk stratification systems, could be useful in the preoperative diagnostic workup and prediction of malignancy, but the evidences are not univocal. Methods: 400 consecutive patients subjected to thyroid surgery were retrospectively enrolled at our institution in Calabria, Southern Italy. Preoperative US and FNA cytological descriptions, formulated according to the “Italian consensus for reporting thyroid fine-needle aspiration cytology” (ICCRTC) classification and three US risk stratification systems (those developed by the American Association of Clinical Endocrinologists, American College of Endocrinology and Associazione Medici Endocrinologi (AACE/ACE/AME), American Thyroid Association (ATA), and American College of Radiology (ACR-TIRADS)), were collected, along with histological results. Results: 147 thyroid cancer cases, in large majority papillary carcinomas, were detected on final histological examination. Almost two-thirds of patients subjected to thyroid surgery for either benign or malignant lesions were female. Patient’s age ≤20 years and between 21–30 years were clinical features associated with increased risk of thyroid cancer in logistic regression analyses. US features associated with thyroid cancer included irregular margins, solid composition, microcalcifications, and marked hypoechogenicity. The AACE/ACE/AME, ATA, and ACR-TIRADS risk categories, corresponding to specific US patterns, were strong predictors of malignancy in both genders, but not in nodules with indeterminate cytology. A measured difference between the longitudinal (L) and the anteroposterior (AP) diameter >5 mm, a proxy for a parallel-oriented oval shape of a nodule, emerged as a robust protective factor against thyroid cancer (OR 0.288 (95%CI 0.817–0.443); p < 0.001), regardless of cytological risk. Conclusions: Some, but not all, well-established predictors of TC have been confirmed in this study. Controversy surrounds the diagnostic performance of US risk stratification systems for the detection of thyroid cancer in the subgroup of nodules with indeterminate cytology, suggesting their use only to set the thresholds for FNA. A measured difference between L and AP diameters >5 mm may represent an additional and practical tool for ruling out malignancy in thyroid nodules, with the potential to reduce unnecessary surgical procedures.

Advanced Ultrasound Application - Impact on Presurgical Risk Stratification of the Thyroid Nodules

Aim

Current major guidelines recommend risk stratification of the thyroid nodules, after each diagnostic evaluation, in order to focus attention on potentially risky nodules. The main aim of our study was to evaluate the performance of combined advanced ultrasound techniques in this process, compared with conventional stratification models, in order to reduce unnecessary fine-needle biopsies, respectively, surgery.

Material and Methods

We evaluated 261 cases (261 nodules) using conventional ultrasound (2B), real-time Doppler evaluation (4D) respectively, real-time elastography, using a linear multifrequency probe and a linear volumetric probe (Hitachi Prerius Machine, Hitachi Inc, Japan). All the nodules were classified using a risk stratification model comprising seven conventional US characteristics, two 4 D characteristics and a color map RTE aspect. The results were compared with the pathology results, considered the golden standard diagnosis.

Results

The prevalence of malignant nodules was 21.83% (57 cases). Conventional risk classification generated: 106 low-risk cases, 113 intermediate-risk and 42 high-risk cases. Our proposed risk classification changes the conventional risk classification with a risk upgrade in 27 cases and with a risk downgrade in 69 cases. The diagnostic quality of the combined risk stratification model was better, considering a low-risk category predictive for benignancy and a high category predictive for malignancy: Sensitivity: 80.88% versus 49.01%, respectively, Specificity: 91.22% versus 54.38. The diagnostic power differences were observed regardless of the nodule size.

Conclusion

Advanced ultrasound techniques did add diagnostic value in the presurgical risk assessment of the thyroid nodules.

Prediction of thyroid nodule malignancy using thyroid imaging reporting and data system (TIRADS) and nodule size

OBJECTIVES

Thyroid imaging reporting and data system (TIRADS) is a combination of ultrasonographic features developed to help physicians in predicting the malignancy risk of thyroid nodules based on sonographic characteristics. Thyroid nodule size is another factor in determining whether a nodule is malignant. The aim of this study was detecting the predictive value of TIRADS and nodule size based on Bethesda classification in prognostication of malignancy.

METHODS

This was a cross-sectional study of 239 patients with thyroid nodules. The patients underwent ultrasonography using TIRADS classification and FNA biopsy based on Bethesda categorization. The results were analyzed using SPSS with the cut off points and predictive values measured.

RESULTS

TIRADS ≥4 could detect malignant nodules with a sensitivity of 91.67% and specificity of 52.8%. An inverse relationship was observed between nodule size and malignancy risk and cutoff point of 12 mm was found for detecting malignant nodules.

CONCLUSIONS

Thyroid nodules with TIRADS 4 and 5 and diameter lower than 12 mm, are highly suspicious for malignancy and should be considered as indications for fine needle aspiration biopsy.

ADVANCES IN KNOWLEDGE

The study suggests TIRADS and thyroid nodule size as sensitive predictors of malignancy.

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.

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.

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.

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.

WOMEN IN CANCER THEMATIC REVIEW: Thyroid-stimulating hormone in thyroid cancer: does it matter?

Differentiated thyroid cancer is the most common endocrine malignancy and the incidence is increasing rapidly worldwide. Appropriate diagnosis and post-treatment monitoring of patients with thyroid tumours are critical. Fine needle aspiration cytology remains the gold standard for diagnosing thyroid cancer, and although there have been significant refinements to this technique, diagnostic surgery is often required for patients suspected to have malignancy. Serum thyroid-stimulating hormone (TSH) is higher in patients with malignant thyroid nodules than in those with benign disease, and TSH is proportionally increased in more aggressive tumours. Importantly, we have shown that the pre-operative serum TSH concentration independently predicts the presence of malignancy in subjects presenting with thyroid nodules. Establishing the use of TSH measurements in algorithms identifying high-risk thyroid nodules in routine clinical practice represents an exciting, cost-efficient and non-invasive approach to optimise thyroid cancer diagnosis. Binding of TSH to receptors on thyrocytes stimulates a number of growth promoting pathways both in normal and malignant thyroid cells, and TSH suppression with high doses of levothyroxine is routinely used after thyroidectomy to prevent cancer recurrence, especially in high-risk tumours. This review examines the relationship between serum TSH and thyroid cancer and reflects on the clinical potential of TSH measurements in diagnosis and disease monitoring.

Malignancy in solitary thyroid nodule: A clinicoradiopathological evaluation

BACKGROUND

Thyroid nodules are common. They can be either benign or malignant. Solitary thyroid nodules (STN) have a high likelihood of being malignant. They should be characterized properly for optimum management.

MATERIALS AND METHODS

In this study, we have analyzed our departmental data over a period of 5 years. All the patients who presented to the outpatient department with a clinically detected STN were included in the study group. Our approach was individualized. Preoperative ultrasonography (USG) and fine-needle aspiration cytology were planned in all these patients. Hemi thyroidectomy and total thyroidectomy with and without neck dissection were performed wherever appropriate.

RESULTS

There were 162 cases of clinically detected STN. USG findings were available in 146 cases. Postoperative histopathology was reported as malignant in 58 cases. Malignant STN was more likely in males. Ultrasonographically detected solid STN were more prone for malignancy as compared to multinodular goiter (P = 0.000) Presence of micro calcification and cervical lymphadenopathy were more commonly noted in malignant thyroid swellings.

CONCLUSION

Solitary thyroid nodules do have a high likelihood of harboring a malignancy. Solid echogenicity, micro calcification and cervical lymphadenopathy on USG were seen more frequently in malignant nodules.

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.

Quantification of cancer risk of each clinical and ultrasonographic suspicious feature of thyroid nodules: a systematic review and meta-analysis

OBJECTIVE

In order to quantify the risk of malignancy of clinical and ultrasonographic features of thyroid nodules (TNs), we did a systematic review and meta-analysis of published studies.

METHODS

We did a literature search in MEDLINE for studies published from 1st January 1989 until 31st December 2012. Studies were considered eligible if they investigated the association between at least one clinical/ultrasonographic feature and the risk of malignancy, did not have exclusion criteria for the detected nodules, had histologically confirmed the diagnoses of malignancy, and had a univariable analysis available. Two reviewers independently extracted data on study characteristics and outcomes.

RESULTS

The meta-analysis included 41 studies, for a total of 29678 TN. A higher risk of malignancy expressed in odds ratio (OR) was found for the following: nodule height greater than width (OR: 10.15), absent halo sign (OR: 7.14), microcalcifications (OR: 6.76), irregular margins (OR: 6.12), hypoechogenicity (OR: 5.07), solid nodule structure (OR: 4.69), intranodular vascularization (OR: 3.76), family history of thyroid carcinoma (OR: 2.29), nodule size ≥4 cm (OR: 1.63), single nodule (OR: 1.43), history of head/neck irradiation (OR: 1.29), and male gender (OR: 1.22). Interestingly, meta-regression analysis showed a higher risk of malignancy for hypoechoic nodules in iodine-sufficient than in iodine-deficient geographical areas.

CONCLUSIONS

The current meta-analysis verified and weighed out each suspicious clinical and ultrasonographic TN feature. The highest risk was found for nodule height greater than width, absent halo sign, and microcalcifications for ultrasonographic features and family history of thyroid carcinoma for clinical features. A meta-analysis-derived grading system of TN malignancy risk, validated on a large prospective cohort, could be a useful tool in TN diagnostic work-up.