The role of repeat fine needle aspiration in the management of indeterminate thyroid nodules

Current controversies in the management of patients with indeterminate thyroid nodules

The management of cytologically indeterminate thyroid nodules remains debatable as their malignancy is difficult to establish. Most nodules have benign postoperative histology, but an accurate assessment of their proclivity for malignant transformation is crucial. Numerous studies have investigated the effects of various tools, including clinical, radiological, and cytological features, as well as biochemical and molecular markers, on the management of these heterogeneous nodules. Collectively, strategies aim to treat malignant nodules and avoid unnecessary surgery for asymptomatic benign nodules. Currently, no clear guidelines for the optimal management of cytologically indeterminate thyroid nodules exist to determine whether a conservative approach with long-term observation or surgical intervention should be selected. Thus, personalized approaches have been recommended. Large-scale multicenter prospective studies are needed to elucidate controversial issues. As this topic has not been comprehensively covered based on publications from the Gulf region, this review aims to shed light on remaining controversies.

Repeat Fine-Needle Aspiration With Molecular Analysis in Management of Indeterminate Thyroid Nodules

OBJECTIVE

To analyze clinical outcomes in a series of indeterminate thyroid nodules (ITNs) with repeat fine-needle aspiration (FNA) biopsy and results of genomic classifier.

STUDY DESIGN

Historical chart review.

SETTING

Tertiary care center.

METHODS

We reviewed FNA samples from subjects with Bethesda III or IV diagnoses from January 2015 to December 2018 at a single institution and selected those with repeat FNA and ThyroSeq testing of the same nodule. Patient demographics, Bethesda classifications, ThyroSeq results, treatment detail, and surgical pathology, when available, were analyzed.

RESULTS

Ninety-six patients with cytologic diagnosis of ITN, repeat FNA, and ThyroSeq testing were identified. Following repeat FNA, 55 nodules (57%) remained ITN; 40 (42%) were reclassified as benign; and 1 (1%) was reclassified as suspicious for malignancy. In 31 patients with ThyroSeq analysis accompanying initial and repeat FNA, 26 (84%) had the same result on each, while 5 (16%) tested ThyroSeq positive following an initially negative result (κ = 0.24). Most nodules that were downgraded to Bethesda II on repeat FNA (37/40, 93%) were managed nonsurgically. Patients with ThyroSeq-positive results were treated with surgery more often (25/28, 89%) than patients with ThyroSeq-negative results (11/68, 16%; P < .0001). In excised nodules, the prevalence of malignancy and noninvasive follicular thyroid neoplasm with papillary-like nuclear features was 28% (n = 10) and 22% (n = 8), respectively, and all malignancies were low risk.

CONCLUSION

In this case series, repeat FNA helped patients with ITNs avoid diagnostic surgery through reclassification to benign cytology. The risk of high-risk malignancy in ThyroSeq-positive nodules with repeat indeterminate cytology was low.

Risk assessment of cytologically indeterminate thyroid nodules with integrated molecular testing and repeat biopsy: a surgical decision-oriented tool

BACKGROUND

The preoperative diagnosis of cytologically indeterminate thyroid nodules (ITNs) is very challenging. In this study, we aim to provide an integrated risk assessment for thyroid nodules with indeterminate cytology to guide surgical decision-making, which includes results of blood tests, molecular tests, and repeat fine-needle aspiration biopsy (FNAB).

METHODS

The study retrospectively included 265 ITNs between June 2019 and April 2022. According to our integrated risk assessment process that starts with blood testing, followed by supplementary DNA mutation detection on the first FNAB, and finally repeat FNAB, we divided the ITNs into high-risk and low-risk groups. Performance was evaluated with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), area under the receiver operating characteristic curve (AUC), and the consistency between the risk evaluation and histological results.

RESULTS

Of the 265 ITNs, 87 were included in the risk assessment process. The risk assessment had a sensitivity of 84.1%, specificity of 83.3%, PPV of 95.1%, NPV of 57.7%, and AUC of 0.837. The nodules with consistent results between the risk groups and histological outcomes, which included malignant cases in the high-risk group and benign cases in the low-risk group, accounted for 83.9% of all risk-assessed nodules.

CONCLUSIONS

These data suggest that the integrated risk assessment might provide proper information for surgical decision-making in patients with ITNs.

Rate of malignancy for thyroid nodules with AUS/FLUS cytopathology in a tertiary care center - a retrospective cohort study

BACKGROUND

Thyroid nodules are stratified through fine-needle aspiration (FNA) and are often categorized using The Bethesda System for Reporting Thyroid Cytopathology, which estimates the risk of malignancy for six cytopathological categories. The atypia of undetermined significance (AUS) and follicular lesion of undetermined significance (FLUS) categories have varying malignancy rates reported in the literature which can range from 6 to 72.9%. Due to this heterogeneity, we assessed the malignancy rate and effectiveness of repeat FNA (rFNA) for AUS/FLUS thyroid cytopathology at our institution.

METHODS

Electronic health records of patients with AUS/FLUS thyroid cytopathology on FNA at our center since the implementation of the Bethesda System on May 1, 2014-December 31, 2019 were retrospectively reviewed. Patient demographics, treatment pathway, and pathology results were collected. The treatment pathway of the nodules, the rFNA results, and the malignant histopathology results were reported. Malignancy rates were calculated as an upper and lower limit estimate.

RESULTS

This study described 182 AUS/FLUS thyroid nodules from 177 patients. In total, 24 thyroid nodules were deemed malignant upon histopathology, yielding a final malignancy rate of 13.2-25.3%. All of the malignancies were variants of papillary thyroid carcinoma. The malignancy rate of the nodules which underwent resection without rFNA (21.5%) was lower than the malignancy rate of the nodules which underwent resection after rFNA (43.8%). 45.5% of the rFNA results were re-classified into more definitive categories.

CONCLUSION

The malignancy rate of AUS/FLUS thyroid cytopathology at our center is in line with the risk of malignancy stated by the 2017 Bethesda System. However, our malignancy rate is lower than some other Canadian centers and approximately half of our rFNAs were re-classified, highlighting the importance of establishing center-specific malignancy and rFNA re-classification rates to guide treatment decisions.

Analysis of Clinical-Radiological-Pathological Factors in FN/SFN Bethesda Category Thyroid Nodules, Contribution of FNAB Repeat, Single Center Experience

Objectives:

Follicular neoplasm/suspected follicular neoplasm (FN/FNS) Bethesda Category (BC)-4 group cases are known as the gray zone. Nodules diagnosed in cytology are excised. However, very few of these nodules are malignant. Our aim is to investigate the usability of clinical-radiological-pathological parameters to reduce unnecessary surgery. In addition, we questioned the benefit of repeating fine-needle aspiration biopsy (rFNAB) in these nodules, which is not recommended, but performed for clinical or patient-related reasons.

Methods:

The files of all thyroid FNAB patients conducted in our institution between January 2014 and September 2020 were scanned in the database. In our study, 185 (5.1%) nodules with cytology results of which were classified as FN/FNS were identified among 3624 nodules that were applied FNAB during this period. Twenty-eight patients were excluded from the study group. 157 nodules belonging to 157 patients between the ages of 21 and 82 years who were operated and met the study criteria were identified from patients with these nodules. The files of all patients were scanned and the results of age, gender, ultrasonographic nodule characteristics, FNAB repeat, type of surgery, and postoperative pathology were recorded. All data were analyzed by comparing them with nodule features. SPSS 15.0 for Windows program was used for statistical analysis.

Results:

A significant correlation was found between the incidence of malignancy and male gender and hypervascularization (p=0.017 and p=0.002, respectively). Malignancy was less in nodules larger than 2 cm (p=0.014). There was no relationship between other clinical and radiological features and malignancy. In 29 nodules with rFNAB, a significant correlation was found between malignancy and advanced age (52.9-years-old), presence of nodules smaller than 2 cm and hypervascularization (p=0.047, p=0.047, and p=0.030, respectively).

Conclusion:

We recommend careful review of patients with hypervascular, hypoechogenic, and microcalcific BC-4 nodules (male gender and older patients at greater risk). Because of the serious risk of malignancy, patients with these features should be prepared for patient management with total thyroidectomy after examination with frozen section applied to the nodule during the operation.

The value of repeating fine-needle aspiration for thyroid nodules

BACKGROUND

Fine-needle aspiration (FNA) is an invaluable technique used in the evaluation of thyroid nodules.

OBJECTIVES

Evaluate the concordance of results for consecutive FNA readings.

DESIGN

Retrospective, descriptive.

SETTINGS

Two tertiary care centers.

METHODS

Demographics were collected along with every FNA result and final pathology results for all patients (aged 9-90 years old) who underwent thyroid surgery from 2010 to 2017. The Bethesda system was used for cytology. Agreement levels were calculated and compared with final pathology.

SAMPLE SIZE

Of 1237 initially included, 1134 had at least one FNA performed with results available for review.

RESULTS

For the 1134 patients, demographic and clinical data were collection and a comparison was made between the three FNA results; the highest agreement was between FNA 2 and 3 (53.6%); however, the kappa value was consistently low for all comparisons, indicating a poor level of agreement overall. Also, the risk of malignancy was higher in this study than in the 2017 Bethesda system for reporting thyroid cytopathology in FNA cytology categories I and II.

CONCLUSION

Repeating FNA biopsies yield different results every time; hence, there is a low level of agreement. The clinical decision should therefore include other important risk factors. Prospective studies could help shed more light on this topic.

LIMITATIONS

Retrospective design.

CONFLICT OF INTEREST

None.

Differential outcomes of patients with thyroid FNA diagnoses of AUS/FLUS with and without nuclear atypia: The potential need for separation in the Bethesda System

BACKGROUND

In the current version of The Bethesda System (TBS) for thyroid cytopathology, the atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) category has an estimated risk of malignancy of 10% to 30%. Diagnostic criteria include presence of nuclear atypia, suggestive of papillary thyroid carcinoma (PTC), as well as other types of atypia, which can be seen with non-malignant entities. Aim of this study was to investigate differential outcomes of AUS/FLUS, based on specific morphologic criteria, and assess their respective malignancy risks.

METHODS

From a total of 1233 patients undergoing thyroid FNAs between 2010 and 2014 at the University of Washington, 119 had AUS/FLUS without nuclear atypia, and 64 with nuclear atypia. Outcomes for patients with and without nuclear atypia (with the exception of 24 patients lost to follow-up) were evaluated and results were compared.

RESULTS

16/57 (28.1%) patients with AUS/FLUS and nuclear atypia subsequently had carcinomas on thyroidectomy, statistically higher than the 8/102 patients (7.8%, P = .001) without nuclear atypia. When comparing only patients who underwent surgery (n = 63), again those with AUS/FLUS and nuclear atypia had statistically higher rates of carcinoma (16/31, 51.6%), compared to those without (8/32, 25%; P = .0394). Overall, 24/159 (15.1%) of patients with AUS/FLUS had carcinoma on subsequent histology.

CONCLUSION

Malignancy rates for AUS/FLUS were in line with TBS estimated risks. However, our data demonstrate that the presence or absence of nuclear atypia is associated with different malignancy rates, suggesting the possibility that the AUS/FLUS category may best be split into two subcategories with different implied risks of malignancy.

Hashimoto's thyroiditis elicits decreased diagnostic efficacy of thyroid nodule ultrasound-guided fine needle aspiration

BACKGROUND

False negative (FN) or false positive (FP) results of thyroid ultrasound-guided fine needle aspiration (US-guided FNA) cause missed diagnosis of thyroid cancer or unnecessary thyroidectomy.

PURPOSE

To explore the impact of Hashimoto's thyroiditis (HT) on the diagnostic efficacy of US-guided FNA and to analyze the differences in diagnostic efficacy between US-guided FNA and thyroid ultrasonography (US) in patients with HT.

METHOD

Medical records were reviewed retrospectively. Patients with and without Hashimoto's thyroiditis (HT) were included in the exposure and non-exposure group, respectively.

RESULTS

HT was not an independent risk factor for thyroid cancer. The percentage of undetermined results of US-guided FNA (Bethesda I, III, IV) in the exposure group was significantly higher. The US-guided FNA's diagnostic sensitivity, specificity, and accuracy were significantly lower, and FP rate (FPR) and FN rate (FNR) were higher in the exposure group. In the exposure group, US tended to give higher diagnostic sensitivity, accuracy, PPV, NPV, and lower FPR and FNR. Receiver operating characteristic (ROC) curve analysis showed that, in the exposure group the diagnostic efficacy of thyroid US was significantly higher than of US-guided FNA.

CONCLUSION

HT tends to cause undetermined results and elicit lower diagnostic performance of US-guided FNA. In patients with HT, the diagnostic efficacy of thyroid US is, at least, not inferior to US-guided FNA.

Core needle biopsy in the management of thyroid nodules with an indeterminate fine-needle aspiration report

Ultrasonography (US)-guided fine-needle aspiration biopsy (FNAB) cytology is widely used but is limited due to its pathologically indeterminate results in diagnosing thyroid nodules. Recently, US-guided core-needle biopsy (CNB) was introduced as an effective and safe technique for diagnosing indeterminate thyroid nodules. Using CNB, information about architectural histologic structure such as nodule capsule or more immunochemical staining can be obtained which lead to a more accurate diagnosis. Up to 98% of indeterminate thyroid lesions can be classified as malignant or benign when CNB is used for follow-up analysis. Other evidences revealed the effectiveness of CNB in reducing inconclusive results and improving the diagnostic performance of thyroid nodules initially diagnosed as AUS/FLUS by FNAB. In this review, we investigate how to deal with indeterminate thyroid nodules diagnosed by FNAB and determine how CNB has a role in diagnosing these indeterminate thyroid nodules.

The role of repeat fine needle aspiration in managing indeterminate thyroid nodules

BACKGROUND

The Bethesda System is the most widely used for reporting fine needle aspiration (FNA) cytology. It recommends a repeat FNA (rFNA) when initial results are category I or III. It is unclear how often rFNA provides additional diagnostic information. We sought to investigate its utility at our institution.

METHODS

A retrospective chart review was performed of patients who had a category I or III FNA result and underwent rFNA of the same thyroid nodule between 2013 and 2015 at the QE II Health Sciences Centre in Nova Scotia, Canada. Results of initial FNA and ultrasound characteristics, rFNA, demographic data, surgical details, and pathology were collected.

RESULTS

A total of 237 patients (474 thyroid FNAs) were included. Most initial FNAs were category I (82%), the remainder category III (18%). rFNA yielded a different category 60% of the time. However, 60% remained category I or III. rFNA results of benign or malignant were found in 40% of cases; 1% were SFN/SFM. Twenty-seven percent of patients had surgery after rFNA; of those 68% had category I or III rFNA results. Of all nodules that underwent surgery, 46% were malignant, including 32% with category I rFNA results, and 42% category III.

CONCLUSIONS

rFNA for category I and III nodules provided a definitive diagnosis in only 40% of cases, which is important for patient counseling. Malignancy rates at our centre were higher for these categories than predicted by Bethesda. Clinical management should consider institution specific malignancy rates, patient factors, and ultrasound findings.

Outcomes of Bethesda categories III and IV thyroid nodules over 5 years and performance of the Afirma gene expression classifier: A single-institution study

OBJECTIVE

The second edition Bethesda System for Reporting Thyroid Cytology estimates 6%-18% malignancy rate of category III (B3) and 10%-40% for category IV (B4) nodules; however, reported malignancy rates have considerable variability among institutions. Use of molecular classifiers (including Afirma Gene Expression Classifier, GEC) can be utilized in management of thyroid nodules. Our objective was to analyse malignancy rates of B3 and B4 nodules and determine clinical outcomes of GEC Benign nodules.

METHODS

A retrospective analysis of 2019 thyroid FNAs was performed at the University of Colorado from 2011 to 2015, including molecular, surgical and clinical follow-up.

RESULTS

Of 2019 FNAs analysed, 231 (11.4%) were diagnosed as B3 and 80 (4.0%) as B4. GEC was obtained in 54.1% of B3 cases, with nearly half (48.8%) having a Benign result. Surgery was performed in 40.7% B3 cases with a 24.5% malignancy rate, ranging 8%-38% by year. In the B4 group, 52.5% underwent molecular testing with 28.6% as GEC Benign. About 68.8% of B4 cases underwent surgery with a 20% malignancy rate, ranging 0%-42% by year. Seventy-three GEC Benign cases were reviewed: 5 (6.8%) underwent surgery, with none demonstrating malignancy in the target nodule. Size remained stable for most GEC Benign nodules: 75.9% (B3) and 71.4% (B4) with no malignancy on repeat FNA.

CONCLUSIONS

Our 5-year review demonstrated that malignancy rates of B3 and B4 nodules showed year-to-year variability. We suggest that clinicians use a multi-year average of their institution's malignancy rates to optimally manage patients. Follow-up for GEC Benign cases thus far supports their indolent nature.

Molecular testing for indeterminate thyroid nodules: Performance of the Afirma gene expression classifier and ThyroSeq panel

BACKGROUND

The ThyroSeq mutational panel and Afirma gene expression classifier (GEC) are used to risk stratify cytologically indeterminate thyroid nodules. In the current study, the authors evaluated the performance of these tests within the context of ultrasonographic features and with the incorporation of the noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) nomenclature.

METHODS

The authors reviewed nodules using ThyroSeq or Afirma GEC testing. For nodules that were surgically resected, both tests were studied within the context of ultrasound findings, comparing performance stratified by the 2015 American Thyroid Association guideline (ATA 2015) sonographic patterns and assessing the positive predictive value (PPV) of these tests both including and excluding NIFTP in the malignant category.

RESULTS

A total of 304 cases were identified, 119 of which were resected. All cases that met the criteria for NIFTP on excision demonstrated either high-risk mutations on ThyroSeq or a "suspicious" result on Afirma GEC. When NIFTP cases were shifted from the malignant to nonmalignant category, the PPV of "positive" tests for both ThyroSeq and Afirma GEC decreased from 42.9% to 14.3% (an absolute decrease of 28.6%) and 30.1% to 25.3% (an absolute decrease of 4.8%), respectively. No cases of malignancy were found in the ATA 2015 "very low suspicion" group, even with a "suspicious" Afirma GEC result.

CONCLUSIONS

Both the ThyroSeq and Afirma GEC tests demonstrated decreases in the PPV when NIFTP was considered nonmalignant. In the era of NIFTP, a "positive" test result for either the Afirma GEC or ThyroSeq should be interpreted in light of clinical factors and should not exclude conservative (ie, lobectomy) surgical management. ATA 2015 "very low suspicion" nodules, even with "suspicious" Afirma GEC results, were not found to demonstrate malignancy in this series. Cancer Cytopathol 2018. © 2018 American Cancer Society.

The Role of Core Needle Biopsy for Thyroid Nodules with Initially Indeterminate Results on Previous Fine-Needle Aspiration: A Systematic Review and Meta-Analysis

BACKGROUND

Sonography-guided fine-needle aspiration leads to relatively frequent cases of indeterminate cytology for the diagnosis of thyroid nodules.

PURPOSE

Our aim was to evaluate the efficacy and safety of core needle biopsy for the examination of thyroid nodules with initially indeterminate results on fine-needle aspiration.

DATA SOURCES

A computerized search of the MEDLINE and Embase databases was performed to identify relevant original articles.

STUDY SELECTION

Studies investigating the use of core needle biopsy for thyroid nodules with initially indeterminate results on previous fine-needle aspiration were eligible for inclusion.

DATA ANALYSIS

The pooled proportions for nondiagnostic results, inconclusive results, malignancy on core needle biopsy, the ability of core needle biopsy to diagnose malignancy, and the related complications of the procedure were analyzed.

DATA SYNTHESIS

The meta-analytic pooling was based on a random-effects model. Nine eligible studies, involving 2240 patients with 2245 thyroid nodules, were included. The pooled proportion for nondiagnostic results was 1.8% (95% CI, 0.4%-3.2%), and the pooled proportion for inconclusive results was 25.1% (95% CI, 15.4%-34.9%). The pooled proportion for malignancy was 18.9% (95% CI, 8.4%-29.5%). With regard to the diagnostic performance for malignancy, the sensitivity of core needle biopsy varied, ranging from 44.7% to 85.0%, but the specificity was 100% in all cases. No major complications of core needle biopsy were observed.

LIMITATIONS

The relatively small number of included studies and retrospective nature were limitations.

CONCLUSIONS

Core needle biopsy has low nondiagnostic result rates and high specificity for the diagnosis of malignancy. It is a safe diagnostic technique with a higher diagnostic yield, especially when molecular testing is not available or fine-needle aspiration did not yield enough cells for molecular testing.