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

Thyroid cytology in pediatric patients: a single-center study from 2015 to 2023-is there a necessity for distinct treatment approaches for patients with and without autoimmune thyroiditis?

The management of thyroid nodules is guided by the cytological classification provided by The Bethesda System for Reporting Thyroid Cytology. Notably, the biology of thyroid tumors in pediatric patients differs from that in adults, and there is limited research focused on pediatric cases. This study aimed to assess the effectiveness of the Bethesda system in pediatric patients treated at the largest tertiary pediatric thyroid center in Poland between 2015 and 2023. A retrospective analysis was conducted on 566 patients with thyroid nodules, of whom 555 underwent fine-needle aspiration biopsy (FNAB). A total of 217 patients underwent thyroid surgery. Of these, 206 had previously undergone FNAB with cytological evaluation at our center, while 11 patients underwent thyroid surgery due to a RET mutation or the need for an extended procedure. The initial FNAB results showed distribution across Bethesda categories as follows: 7.6% for category I, 54.6% for category II, 20.9% for category III, 4.1% for category IV, 7.6% for category V, and 5.6% for category VI. Among patients who underwent surgery, the distribution of Bethesda categories I through VI was 2.9%, 25.2%, 29.1%, 8.3%, 19.4%, and 15%, respectively. The risk of malignancy (ROM) from the initial FNAB was estimated at 33.3%, 11.5%, 22.2%, 4.8%, 84.4%, and 96.8% for Bethesda categories I through VI, respectively. In patients with autoimmune thyroiditis (AIT), the ROM was higher than in non-AIT patients for Bethesda categories I through IV, while it was lower in category VI. The sensitivity for detecting non-benign neoplasms across Bethesda categories III through VI was approximately 86% in both AIT and non-AIT patients. However, for papillary thyroid carcinoma, sensitivity in Bethesda categories V and VI was 86% in non-AIT patients but decreased to 61.5% in AIT patients. These findings emphasize the importance of considering surgical intervention in pediatric patients with Bethesda III-VI cytology, particularly in those with AIT.

Clinical risk factors and cancer risk of thyroid imaging reporting and data system category 4 A thyroid nodules

PURPOSE

Beyond the Thyroid Imaging Reporting and Data System (TIRADS) classification of thyroid nodules, additional factors must be weighed in the decision to perform fine needle aspiration (FNA). In this study, we aimed to identify risk factors for malignancy in patients with ultrasound-classified Chinese-TIRADS (C-TIRADS) 4 A nodules.

METHODS

Patients who underwent thyroid FNA at our institution between May 2021 and September 2022 were enrolled. We collected demographic data, including age, sex, previous radiation exposure, and family history. An in-person questionnaire was used to collect lifestyle data, such as smoking habits and alcohol consumption. Body mass index (BMI) was calculated. The serum levels of thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TGAb) were measured. Prior to FNA, ultrasonic inspection reports were reviewed. The cytologic diagnoses for FNA of thyroid nodules followed the Bethesda System for Reporting Thyroid Cytopathology (2017).

RESULTS

Among the 252 C-TIRADS 4 A nodules, 103 were malignant. Compared to those in the benign group, the patients in the malignant group had a younger age (42.2 ± 13.6 vs. 51.5 ± 14.0 years, P < 0.001). Logistic regression showed that advanced age was associated with a lower risk of malignancy in C-TIRADS 4 A nodules (OR = 0.95, 95% CI 0.93 ~ 0.97, P < 0.001). We demonstrated a decreased risk of malignancy in patients with 48.5 years or older.

CONCLUSION

Advanced age was associated with a decreased risk of malignancy in patients with C-TIRADS 4 A nodules. This study indicated that in addition to sonographic characteristics, patient age should be considered when assessing the risk of malignancy.

Do large thyroid nodules (≥4 cm) without suspicious cytology need surgery?

Background

Fine-needle aspiration biopsy (FNAB) is a good diagnostic tool for thyroid nodules; however, its high false-negative rate for giant nodules remains controversial. Many clinicians recommend surgical resection for nodules >4 cm owing to an increased risk of malignancy and an increased false-negative rate. This study aimed to examine the feasibility of this approach and investigate the incidence of malignancy in thyroid nodules >4 cm without suspicious cytology based on medical records in our center.

Methods

This was a retrospective analysis of 453 patients that underwent preoperative FNAB for nodules measuring >4 cm between January 2017 and August 2022 at Severance Hospital, Seoul.

Results

Among the 453 patients, 140 nodules were benign and 119 were indeterminate. Among 259 patients, the final pathology results were divided into benign (149) and cancerous (110) groups, and the prevalence of malignancy was 38.9% in the benign group and 55.5% in the indeterminate group. Among the malignancies, follicular carcinoma and follicular variants of papillary carcinoma were observed in 83% of the cytologically benign group and 62.8% of the indeterminate group.

Conclusion

Preoperative FNAB had high false-negative rates and low diagnostic accuracy in patients with thyroid nodules >4 cm without suspicious cytologic features; therefore, diagnostic surgery may be considered a treatment option.

Delayed Cancer Diagnosis in Thyroid Nodules Initially Treated as Benign With Radiofrequency Ablation: Ultrasound Characteristics and Predictors for Cancer

OBJECTIVE

Regrowth after radiofrequency ablation (RFA) of symptomatic large thyroid nodules, initially treated as benign, sometimes turns out to be malignancies. This study aimed to assess the ultrasound (US) characteristics of thyroid nodules initially treated as benign with RFA and later diagnosed as cancers, predictive factors for cancers masquerading as benign, and methods to avoid RFA in these cancers.

MATERIALS AND METHODS

We reviewed the medical records of 134 consecutive patients with 148 nodules who underwent RFA between February 2008 and November 2016 for the debulking of symptomatic thyroid nodules diagnosed as benign using US-guided biopsy. We investigated the pre-RFA characteristics of the thyroid nodules, changes at follow-up after RFA, and the final surgical pathology.

RESULTS

Nodule regrowth after RFA was observed in 36 (24.3%) of the 148 benign nodules. Twenty-two of the 36 nodules were surgically removed, and malignancies were confirmed in seven (19.4% of 36). Of the 22 nodules removed surgically, pre-RFA median volume (range) was significantly larger for malignant nodules than for benign nodules: 22.4 (13.9-84.5) vs. 13.4 (7.3-16.8) mL (P = 0.04). There was no significant difference in the regrowth interval between benign and malignant nodules (P = 0.49). The median volume reduction rate (range) at 12 months was significantly lower for malignant nodules than for benign nodules (51.4% [0-57.8] vs. 83.8% [47.9-89.6]) (P = 0.01). The pre-RFA benignity of all seven malignant nodules was confirmed using two US-guided fine-needle aspirations (FNAs), except for one nodule, which was confirmed using US-guided core-needle biopsy (CNB). Regrown malignant nodules were diagnosed as suspicious follicular neoplasms by CNB. Histological examination of the malignant nodules revealed follicular thyroid carcinomas, except for one follicular variant, a papillary thyroid carcinoma.

CONCLUSION

Symptomatic large benign thyroid nodules showing regrowth or suboptimal reduction after RFA may have malignant potential. The confirmation of these nodules is better with CNB than with FNA.

Comparative analysis of accuracy between fine-needle aspiration biopsy and postoperative histopathology for detecting large thyroid nodules: A retrospective observational study

To avoid unnecessary surgeries, ultrasound-guided fine-needle aspiration biopsy (FNAB) is an effective and reliable procedure for the preoperative evaluation of thyroid nodules. However, there have been only a limited number of studies exploring the ability of preoperative FNAB to distinguish malignancy compared to postoperative histopathology in thyroid nodules larger than 4 cm. The aim of this study was to investigate the diagnostic accuracy of FNAB compared to postoperative histopathology in distinguishing malignancy in thyroid nodules larger than 4 cm. A single-center retrospective observational study was conducted at Dr. Zainoel Abidin Hospital, Banda Aceh, Indonesia, between January 2014 and December 2018. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were calculated. A total of 83 patients were included in the study. The results showed that preoperative FNAB may have the ability to distinguish malignancy compared to postoperative histopathology. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 42.85%, 98.38%, 90.00%, 83.56%, and 84.33%, respectively. These data suggested that ultrasound-guided preoperative FNAB is a reliable diagnostic tool in the preoperative evaluation of thyroid nodules larger than 4 cm, but it has limited capability in distinguishing malignancies. In conclusion, although FNAB may be useful in reducing unnecessary surgeries, histopathology remains the preferred method for confirming malignancy in thyroid nodules.

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.

Comparison Study of FNAC Using the Milan System Cytopathology versus Definitive Histology for the Diagnosis of Salivary Gland Tumors

INTRODUCTION

Salivary gland tumors (SGT) represent 6 to 8 percent of head and neck tumors. The cytologic diagnosis of SGT is performed by fine-needle aspiration cytology (FNAC) with variable sensitivity and specificity. The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) categorizes the cytological results and provides the risk of malignancy (ROM). The aim of our study was to evaluate the cytological findings with the definitive pathological findings to assess the sensitivity, specificity, and diagnostic accuracy of FNAC in SGT according to MSRSGC classification.

METHOD

An observational, retrospective, single-center study was carried out at a tertiary referral hospital over a period of 10 years. Patients that underwent FNAC for major SGT and that have undergone surgery to remove the tumor were included. A histopathological follow-up was performed on the surgically excised lesions. Results from the FNAC were categorized into one of the six MSRSGC categories. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of FNAC for determining benign and malignant cases were calculated.

RESULTS

A total of 417 cases were analyzed. The cytological prediction of ROM was 10% in nondiagnostic, 12.12% in non-neoplastic, 3.58% in neoplasm benign group, 60% in AUS and SUMP groups, and 100% in suspicious and malignant group. The statistical analysis of sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for determining benign cases was 99%, 55%, 94%, 93%, and 94%, respectively, and for determining malignant neoplasm was 54%, 99%, 93%, 94%, and 94%, respectively.

CONCLUSION

In our hands, MSRSGC is highly sensitive for benign tumors and highly specific for malignant tumors. The low sensitivity to differentiate malignant from benign cases makes it necessary to apply an adequate anamnesis, physical examination, and imaging tests to consider surgical treatment in most cases.

Ultrasound classification of thyroid nodules: does size matter?

Objective

To determine whether the size of thyroid nodules in ACR-TIRADS ultrasound categories 3 and 4 is correlated with the Bethesda cytopathology classification.

Methods

Thyroid nodules (566) subclassified as ACR-TIRADS 3 or 4 were divided into three size categories according to American Thyroid Association guidelines. The frequency of different Bethesda categories in each size range within ACR-TIRADS 3 and 4 classifications was analyzed.

Results

Most nodules in both ACR-TIRADS classifications fell in the Bethesda 2 category, regardless of size (90.8% and 68.6%, ACR-TIRADS 3 and 4 respectively). The prevalence of Bethesda 6 nodules in the ACR-TIRADS 4 group was 14 times higher than in the ACR-TIRADS 3 group. There were no significant differences between nodule size and fine needle aspiration biopsy classification in any of the ACR-TIRADS categories.

Conclusion

Size does not appear to be an important criterion for indication of fine needle aspiration biopsy in thyroid nodules with a high suspicion of malignancy on ultrasound examination.

Navigating the Debate on Managing Large (≥4 cm) Thyroid Nodules

PURPOSE

Discordant practice guidelines for managing large thyroid nodules may result in unnecessary surgeries and costs. Recent data suggest similar false-negative rates in fine needle aspiration (FNA) biopsies between small (<4 cm) and large (≥4 cm) nodules, indicating that monitoring rather than surgery may be appropriate for large biopsy-negative nodules. We investigated the management of thyroid nodules ≥4 cm to determine the proportion of surgeries not necessary for diagnostic purposes and examined for potential predictors.

METHODS

This was a retrospective cohort study of patients who received a FNA of nodule(s) ≥4 cm between 11/1/2014 and 10/31/2019 at the University of Vermont Medical Center. A surgery was considered unnecessary if the FNA result was benign in the absence of any of the following: compressive symptoms, family history of thyroid cancer in a first degree relative, history of neck irradiation, toxic nodule or toxic multinodular goiter, or substernal extension. Data were analyzed with Wilcoxon rank sum tests, chi square, or Fisher's exact tests.

RESULTS

177 patients had a ≥4 cm nodule during the timeframe and half (54.2%) had surgery. Patients who underwent surgery were significantly younger (51.5 years vs. 62 years; P < 0.001), more likely to report obstructive symptoms (34.4% vs. 12.1%; P < 0.001) and had a larger nodule size (5.0 cm vs. 4.7 cm; P=0.26). Forty-one patients with benign (Bethesda II) FNA results had surgery, all with negative surgical pathology. Thirteen percentage (23/177) of surgeries were potentially not necessary for diagnostic purposes.

CONCLUSION

Approximately half of our patients with ≥4 cm nodules had surgery, with 13% having surgery not necessary for diagnostic purposes revealing opportunities for improving care and costs.

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.

Thyroglobulin Measurement Through Fine-Needle Aspiration for Optimizing Neck Node Dissection in Papillary Thyroid Cancer

BACKGROUND

Thyroglobulin measurement in fine-needle aspiration (FNA-Tg) is an additional diagnostic tool of lymph node metastasis (LNM) in papillary thyroid carcinoma (PTC). However, its performance as a preoperative indicator of lateral neck LNM in PTC is unclear. We evaluated the use of FNA cytology and FNA-Tg to detect neck LNM presurgery using a simple methodology, and established a cut-off value for diagnosing LNM in PTC.

METHODS

We performed a retrospective cohort study based on hospital records, including 299 FNA-Tg measurements from 228 patients with PTC. The cut-off value for FNA-Tg was obtained through a receiver operating characteristic (ROC) curve analysis. The relationships between various parameters and FNA-Tg were analyzed using Spearman's correlation.

RESULTS

Of 299 lymph nodes (LNs) from 228 patients following surgery, 151 were malignant and 148 were benign. The median FNA-Tg levels were 414.40 ng/mL and 6.36 ng/mL in the metastatic and benign LNs, respectively. An FNA-Tg cut-off value of 28.3 ng/mL had the best diagnostic performance (93.38% sensitivity, 70.27% specificity, area under the ROC curve [AUC] 0.868) in the whole cohort. The diagnostic value performed better in the lateral neck group (level II-V, n = 163) than in the central neck group (level VI, n = 136); in the lateral neck group, the sensitivity and specificity of the FNA-Tg cut-off (16.8 ng/mL) were 96.25% and 96.36%, respectively.

CONCLUSIONS

FNA-Tg is a useful technique for the diagnosis of LNM before surgery, especially in lateral neck dissection.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR1900028547.

Update on the Evaluation of Thyroid Nodules

Thyroid nodules (TN) are prevalent in the general population and represent a common complaint in clinical practice. Most are asymptomatic and are associated with a 7%-15% risk of malignancy (1). Methods: PubMed and Medline were searched for articles with a focus on the epidemiology, diagnosis, and management of TN over the past 5 y. Results: The increase in frequency of imaging has led to a rise in the incidence of incidentally diagnosed TN. The initial evaluation of a TN includes assessing thyroid function, clinical risk factors, and neck imaging. Ultrasound remains the gold standard for assessing TN morphology, and biopsy is the standard method for determining whether a TN is benign. Recently published risk stratification systems using morphologic characteristics on ultrasonography have been effective in reducing the number of unnecessary biopsies. Advances in molecular testing have reduced the number of surgical procedures performed for diagnostic purposes on asymptomatic TN with indeterminate cytology. Scintigraphy is the first-line study for assessing a hyperfunctioning nodule. Many TN can be followed clinically or with serial ultrasound after the initial diagnosis. Surgical intervention is warranted when local symptoms are present, in patients with clinical risk factors, as well as in most situations with malignant cytology. Active surveillance is an option in cases of micropapillary thyroid cancer. Emerging nonsurgical approaches for treating TN include ethanol ablation for TN; sclerotherapy for thyroid cysts; and thermal techniques, such as radiofrequency ablation, laser ablation, microwaves, and high-intensity focused ultrasound. Conclusion: Most TN are benign and can be safely monitored. The indications for biopsy and frequency of imaging should be tailored on the basis of risk stratification. Treatment options should be individualized for each patient's particular situation. Active surveillance should be considered in certain cases of papillary microcarcinoma.

The Role of Cytology in the Diagnosis of Subcentimeter Thyroid Lesions

Thyroid nodules are common and typically detected by palpation and/or ultrasound (US). Guidelines have defined the management of large nodules, but controversy exists regarding nodules ≤ 1 cm. We evaluated a cohort of patients with subcentimeter nodules to determine their rate of malignancy (ROM). A total of 475 thyroid FNAs of lesions ≤ 1 cm with available follow-up were identified from January 2015–December 2019. For comparative analysis, we added a control series of 606 thyroid lesions larger than 1 cm from the same reference period. All aspirates were processed with liquid-based cytology and classified according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). Subcentimeter nodules were stratified as 35 category I—non-diagnostic cases (ND; 7.3%), 144 category II—benign lesions (BL; 30.3%), 12 category III—atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS; 2.5%), 12 category IV—follicular neoplasm/suspicious for follicular neoplasm (FN/SFN; 2.5%), 124 category V—suspicious for malignancy (SM; 26.1%), and 148 category VI—positive for malignancy (PM; 31.1%). A total of 307 cases (64.6%) underwent subsequent surgery. Only one ND and three BLs had a malignant outcome. ROM for indeterminate lesions (III + IV) was 3.2%; with 1.6% for category III and 3.2% for category IV. ROM for the malignant categories (V + VI) was 88.2%. The control cohort of lesions demonstrated a higher number of benign histological diagnoses (67.3%). We documented that 57.2% of suspected subcentimeter lesions were malignant, with a minor proportion that belonged in indeterminate categories. There were very few ND samples, suggesting that aspirates of subcentimeter lesions yield satisfactory results. Suspected US features in subcentimeter lesions should be evaluated and followed by an interdisciplinary team for appropriate patient management.

The global epidemic of thyroid cancer overdiagnosis illustrated using 18 months of consecutive nodule biopsy correlating clinical priority, ACR-TIRADS and Bethesda scoring

Low thyroid cancer mortality worldwide has not been altered by decades of increasing radiological, pathological and surgical intervention for thyroid nodules. Ultrasound-based risk stratification of thyroid nodules, such as TIRADS, has been introduced to reduce intervention for the 'global epidemic' of thyroid cancer 'overdiagnosis'. This article illustrates the use of TIRADS at a New Zealand tertiary centre, during its introduction, with all nodules undergoing fine-needle aspiration biopsy (FNAB) correlated with clinical referral priority and cytological Bethesda score. The correlation between TIRADS and Bethesda score was not significant but cytology had a strong association with clinical priority. Accuracy of TIRADS was poor though the risk of malignancy for TIRADS 5 nodules was 5.1 times those rated as TIRADS 3. After TIRADS was introduced, there was no significant trend in the proportion of malignant nodules diagnosed by FNAB. Despite an incomplete TIRADS programme, the ACR targets of malignancy rates were achieved. The number of patients, as well as the number of nodules per patient, referred for FNAB continues to rise. Changing papillary thyroid cancer nomenclature and other control measures by health policymakers, such as adjustments to payment systems, may be justified. Radiologists are wasting precious health resources that can be better deployed. The use of TIRADS is expensive and a symptom of health policy failure. Clear recommendations from professional societies to not report incidental small thyroid nodules may be a useful start. Whether TIRADS merits continuing use and promotion should be further investigated.

The comparison of the histopathological results of the thyroid fine-needle aspiration biopsies in the 795 patients with thyroidectomy

BACKGROUND

We aimed to evaluate the effectiveness of preoperative fine-needle aspiration biopsies (FNAB) by the postthyroidectomy pathology results.

METHOD

Seven hundred and ninety-five patients with FNAB and following thyroid operations which have been performed between April 2008 and December 2019 were included in this study. By comparing the results of the FNAB and final pathologies, the specificity, sensitivity, FNR, false positivity ratio (FPR), accuracy and also the effect of nodule diameter on these have been evaluated. In Bethesda III subgroup according to FNAB, we investigated the malignancy rates and in whom this risk has been increased more.

RESULTS

In our study, the sensitivity of FNAB is 73.40%, the specificity is 95.33%, the accuracy is 91.81%, FNR is 26.60% and FPR is 4.67%. In the patients with nodules ≥4 cm and < 4 cm respectively, we calculated the sensitivity 20.0% vs 79.76%, specificity 95.73% vs 95.19%, accuracy 89.82% vs 92.78%, FNR 80.0% vs 20.24%, FPR 4.27% vs 4.8%.

CONCLUSION

Thyroid FNAB is an easy procedure with a high specificity and sensitivity. Nevertheless, when the nodule diameter was ≥4 cm, increased FNR and decreased sensitivity should be kept in mind while evaluating the patients.

Is patient age associated with risk of malignancy in a ≥4 cm cytologically benign thyroid nodule?

BACKGROUND

Current data regarding the risk of malignancy in a large thyroid nodule with benign fine-needle aspiration biopsy(FNAB) is conflicting. We investigated the impact of patient age on the risk of malignancy in nodules≥4 cm with benign cytology.

METHODS

We performed a single-institution retrospective review of patients who underwent surgery from 07/2008-08/2019 for a cytologically benign thyroid nodule ≥4 cm. The relationship between malignant histopathology and patient and ultrasound features was assessed with multivariable logistic regression.

RESULTS

Of 474 nodules identified, 25(5.3%) were malignant on final pathology. In patients <55 years old, 21/273(7.7%) nodules were malignant, compared to 4/201(2.0%) in patients ≥55. Patient age ≥55 was independently associated with significantly lower risk of malignancy(OR:0.2,95%CI:0.1-0.7,p = 0.011). Increasing nodule size >4 cm and high-risk ultrasound features were not associated with risk of malignancy(OR:1.0,95%CI:0.7-1.4,p = 0.980, and OR:9.6,95%CI:0.9-107.8,p = 0.066, respectively).

CONCLUSIONS

Patients <55 years old are 3.7-fold more likely to have a falsely benign FNA biopsy in a nodule≥4 cm.

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.

High-Score US-Suspicious Subcentimeter Thyroid Nodules: What Factors Affect Adequate Sampling of US-Guided Fine-Needle Aspiration Biopsy?

BACKGROUND

Fine-needle aspiration biopsy (FNAB) is diagnostic standard for thyroid nodules. However, the influence of adequate sample rate of US-guided FNAB for subcentimeter thyroid nodules is not known well.

OBJECTIVES

To assess the factors affecting adequate sample rate of US-guided FNAB for subcentimeter thyroid nodules.

METHODS

Three hundred and forty-nine consecutive US-guided FNAB procedures were performed in 344 patients with subcentimeter thyroid nodules. The adequate sample rate was analyzed for all nodules on the basis of nodule-related and technical factors. The factors affecting adequate sample rate of US-guided FNAB for subcentimeter thyroid nodules were determined by multivariate logistic regression.

RESULTS

The adequate sample rate increased with larger nodules (72.7% for 3-6 mm nodules and 84.9% for 7-10 mm nodules (P=0.007)). The adequate sample rate was 63.9%, 81.3%, and 90.6% in nodules with macrocalcifcation, microcalcification, and no calcification, respectively (P < 0.001). The adequate sample rate was 71.8% for biopsies performed with a perpendicular needle path and 85.0% with a parallel needle path (P=0.004). The significant factors affecting adequate sample rate of US-guided FNAB for subcentimeter thyroid nodules were nodule size (P < 0.001; odds ratio (OR) for 7-10 mm nodules was approximately 3.0 times higher than that for 3-6 mm nodules), calcification (P < 0.001; OR for nodules without calcification was approximately 5.3 times higher than that for the nodules with macrocalcification), and needle path (P=0.044; OR for the use of the parallel needle path was about 1.8 times higher than that for the perpendicular needle path).

CONCLUSION

Nodule size, calcification, and needle path were the determinants of sample adequacy. The adequate sample rate was higher in larger nodules, in nodules without calcification, and upon using a parallel needle path for biopsy.

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.

Impact of ultrasound-guided fine needle aspiration cytology for diagnosis of thyroid nodules

BACKGROUND

Previous clinical studies have reported that ultrasound-guided fine needle aspiration cytology (UGFNAC) can be used for the diagnosis of thyroid nodules (TN) effectively. However, no study has systematically explored its diagnosis accuracy in patients with TN. Thus, this study will assess its diagnosis accuracy for TN.

METHODS

We will perform a comprehensive literature search from the following databases from their inceptions to the present without language restrictions: MEDILINE, EMBASE, Cochrane Library, Web of Science, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure. We will consider all case-controlled studies investigating the impacts of UGFNAC diagnosis for patients with TN for inclusion. Two authors will independently carry out study selection, data collection, and methodological quality assessment. Quality Assessment of Diagnostic Accuracy Studies tool will be used for methodological quality evaluation. We will use RevMan V.5.3 and Stata V.12.0 software to perform statistical analysis.

RESULTS

We will apply sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio to judge the diagnostic accuracy of UGFNAC for TN.

CONCLUSION

The results of this study will provide latest evidence for the diagnostic accuracy of UGFNAC for TN.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019138805.

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.

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.

2017 Thyroid Radiofrequency Ablation Guideline: Korean Society of Thyroid Radiology

Thermal ablation using radiofrequency is a new, minimally invasive modality employed as an alternative to surgery in patients with benign thyroid nodules and recurrent thyroid cancers. The Task Force Committee of the Korean Society of Thyroid Radiology (KSThR) developed recommendations for the optimal use of radiofrequency ablation for thyroid tumors in 2012. As new meaningful evidences have accumulated, KSThR decided to revise the guidelines. The revised guideline is based on a comprehensive analysis of the current literature and expert consensus.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSION

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