Core-needle biopsy versus repeat fine-needle aspiration for thyroid nodules initially read as atypia/follicular lesion of undetermined significance

Comparison of core-needle biopsy and repeat fine-needle aspiration biopsy for thyroid nodules with initially inconclusive findings: a systematic review, diagnostic accuracy meta-analysis, and meta-regression

INTRODUCTION

The rate of nondiagnostic and indeterminate cytology findings from fine-needle aspiration biopsy (FNAB) is quite high, resulting in repeated puncture and unnecessary surgery. The primary objective of this investigation is to compare diagnostic accuracy of core-needle biopsy (CNB) with repeat FNAB for thyroid nodules with initially inconclusive (nondiagnostic and/or atypia of undetermined significance) FNAB results.

MATERIALS AND METHODS

A thorough search was performed on the Cochrane Library, Scopus, Europe PMC, and Medline databases until October 20th, 2024, employing a combination of pertinent keywords. This review incorporates literature that examines the comparison between CNB and repeat FNAB for thyroid nodule. Pooled odds ratio (OR) of nondiagnostic and inconclusive findings of CNB and repeat FNAB were calculated. A meta-analysis was conducted to assess the diagnostic accuracy of both biopsy methods for malignancy diagnosis utilizing a bivariate random-effects model.

RESULTS

A total of 9 studies were incorporated. The results of our meta-analysis indicated lower rate of nondiagnostic (OR 0.12; 95% confidence interval [CI]: 0.06-0.23, P < 0.00001), atypia of undetermined significance (OR 0.34; 95%CI: 0.21-0.56, P < 0.0001), and inconclusive (OR 0.12; 95%CI: 0.07-0.22, P < 0.00001) findings from CNB compared to repeat FNAB. CNB also exhibited markedly superior cumulative sensitivity estimates (75.1%) compared to repeat FNAB (56.5%), however cumulative specificity did not show a significant difference between CNB (99.9%) and repeat FNAB (99.7%). No patients who received CNB or repeat FNAB encountered any major complications.

CONCLUSIONS

Our study suggests that CNB can be employed to diagnose thyroid nodules that were previously inconclusive on FNAB, rather than repeating the FNAB procedure.

Superior Diagnostic Yield of Core Needle Biopsy Over Fine Needle Aspiration in Diagnosing Follicular-Patterned Neoplasms: A Multicenter Study Focusing on Bethesda IV Results

OBJECTIVE

To compare the diagnostic outcomes of core needle biopsy (CNB) and fine-needle aspiration (FNA) using Bethesda IV as a test-positive criterion for diagnosing follicular-patterned neoplasms in a large multicenter cohort.

MATERIALS AND METHODS

This retrospective study included 5463 thyroid nodules ≥1 cm from 4883 patients (4019 females, 864 males; mean age 53.8 years) that underwent FNA or CNB across 26 hospitals in Korea between June and September 2015. The final diagnosis in cases diagnosed as Bethesda IV (follicular neoplasm) in biopsies were confirmed by surgical pathology. The primary study outcome was the diagnostic yield, defined as the proportion of nodules with follicular-patterned neoplasms confirmed at surgery after receiving Bethesda IV results on biopsy (FNA or CNB), among all that underwent biopsy. Secondary outcomes included false referral rate (FRR) and positive predictive value (PPV). All nodules were analyzed before matching (823 and 4640 nodules for CNB and FNA, respectively) and after nodule matching in a 1:2 ratio (799 and 1571 nodules, respectively) according to age, sex, nodule size, and Korean Thyroid Imaging Reporting and Data System (K-TIRADS) category. Additionally, the diagnostic yields of various histological subtypes of follicular-patterned neoplasms and nodule subgroups were analyzed.

RESULTS

CNB demonstrated a significantly higher diagnostic yield than FNA both before (9.0% vs. 0.5%; P < 0.001) and after matching (9.0% vs. 0.6%; P < 0.001). CNB consistently had higher diagnostic yields than FNA for most histological subtypes and all subgroups. FRR was not significantly different between the CNB and FNA groups after matching (0.4% vs. 0.1%; P = 0.337). The PPV was consistently greater than 90% for both methods, with no significant difference.

CONCLUSION

CNB had a higher diagnostic yield than FNA for follicular-patterned neoplasms, with no significant difference in FRR using Bethesda IV as the test-positive criterion.

A simplified four-tier classification for thyroid core needle biopsy

PURPOSE

To propose a simplified histological classification for core-needle biopsy (CNB) of thyroid nodules with four diagnostic categories (DC) and provide the risk of malignancy (ROM) and the expected incidence for each DC. There is no uniform scheme for categorizing CNB specimens, except for a Korean diagnostic classification similar to the Bethesda system for FNAC.

METHODS

Data from a single institution using CNB as a routine diagnostic tool for thyroid nodules. Biopsies were classified as non-diagnostic, benign, follicular tumour (FT) or malignant. The frequency of each DC and the correlation with surgical pathology of nodules undergoing surgery after CNB were evaluated.

RESULTS

Of 6284 CNBs on 5782 nodules [195 (3.1%) non-diagnostic, 5043 (80.3%) benign, 435 (6.9%) FT and 611 (9.7%) malignant], 1914 nodules (33.1%) underwent surgery after 2016 CNBs: 48 non-diagnostic, 1035 benign, 355 FT and 578 malignant. Malignancy was diagnosed after surgery in 11 non-diagnostic (ROM: 22.9%), 23 benign (ROM: 2.2%), 44 FT (ROM: 12.4%, 11.5% excluding low-grade malignancy) and 568 malignant CNBs (ROM: 98.3%, 93.8% excluding low-grade malignancy). Sensitivity and positive predictive value for malignancy of FT or malignant CNB were 94.7% and 65.6%, and for thyroid neoplasm (adenoma or carcinoma) were 93.2% and 92.6%.

CONCLUSIONS

Our diagnostic classification for CNB of thyroid nodules has a high diagnostic accuracy with a low rate of indeterminate categories. This classification, applied in a Western practice, shows a low ROM for nodules classified as follicular tumours, which could be improved with immunohistochemical studies.

Diagnostic implication of thyroid spherules for cytological diagnosis of thyroid nodules

OBJECTIVE

Thyroid fine-needle aspiration (FNA) is a principal diagnostic procedure for thyroid nodules. A specific cytomorphological structure, known as the thyroid spherule, is often seen in FNA specimens. The clinical significance of these spherules in terms of diagnosis and prevalence remains largely unexplored.

METHODS

We performed a retrospective study on 310 thyroid FNA specimens and categorized them according to the Bethesda System for Reporting Thyroid Cytopathology. The presence, size and number of thyroid spherules in each specimen were examined and these data were subsequently correlated with the clinicopathological features.

RESULTS

Thyroid spherules were almost exclusively detected in benign cases, comprising 7.6% of all benign diagnoses. The average diameter of spherules in benign cases was 84.9 μm. Benign cases and cases with atypia of undetermined significance cases primarily exhibited low cellularity, while follicular neoplasms and malignant cases typically showed moderate to high cellularity. In the subgroup of FNA cases with moderate to high cellularity, spherules were identified in 12 (20%) of 59 benign FNA cases. Within this group, the sensitivity and specificity of thyroid spherules for detecting benign FNA cases were 20% and 100%, respectively.

CONCLUSIONS

Our results suggest that the presence of thyroid spherules in FNA specimens can serve as a highly specific marker for benign thyroid conditions. The prevalence of spherule detection is strongly influenced by the cellularity. In cases with moderate to high cellularity, the identification of spherules can assist the cytopathologists in diagnosing thyroid FNA cases as benign.

A comparative analysis of core needle biopsy and repeat fine needle aspiration in patients with inconclusive initial cytology of thyroid nodules

Purpose

To assess and compare the effectiveness of ultrasound-guided core needle biopsy (CNB) in comparison to repeat fine-needle aspiration(rFNA) for thyroid nodules that yield inconclusive results following the initial fine-needle aspiration (FNA).

Methods

A cohort of 471 patients who received an inconclusive cytological diagnosis following the initial FNA were included in this study. These patients subsequently underwent either CNB (n=242) or rFNA (n=229). The inconclusive FNA results encompassed categories I, III, and IV of The Bethesda System for Reporting Thyroid Cytopathology(TBSRTC), as well as the ultrasound images indicating malignancy despite FNA results falling under TBSRTC category II. This study assessed the sampling satisfaction rate, diagnostic efficacy, and complications associated with CNB compared to rFNA. Additionally, the impact of repeat puncture time and nodule size on diagnostic efficacy was analyzed.

Results

Following repeat punctures, the satisfaction rate of the CNB sampling was found to be significantly higher than that of rFNA (83.9% vs 66.8%). The diagnostic rate in the CNB group was significantly greater compared to that of the rFNA group (70.7% vs 35.8%). In patients with nodule maximum diameters ranging from 5 mm to 20 mm, the diagnostic accuracy was significantly higher in the CNB group compared to that in the rFNA group. In patients with intervals less than 90 days, between 90 days and one year, the diagnostic rate in the CNB group was found to be higher compared to that in the rFNA group. In CNB, not immediately adjacent to the capsule was a risk factor for nodular puncture bleeding (37.0% vs 22.7%.).

Conclusion

CNB demonstrated higher rates of satisfaction and diagnosis compared to the rFNA. The diagnostic effectiveness of CNB was not influenced by the time interval or the size of the thyroid nodule. Therefore, in cases where the initial FNA diagnosis of thyroid nodules is inconclusive, CNB should be considered as a viable option for re-puncture.

Combined fine-needle aspiration with core needle biopsy for assessing thyroid nodules: a more valuable diagnostic method?

PURPOSE

This study aimed to evaluate the diagnostic value of combined fine-needle aspiration (FNA) with core needle biopsy (CNB) in thyroid nodules.

METHODS

FNA and CNB were performed simultaneously on 703 nodules. We compared the proportions of inconclusive results and the diagnostic performance for malignancy among FNA, CNB, and combined FNA/CNB for different nodule sizes.

RESULTS

Combined FNA/CNB showed lower proportions of inconclusive results than CNB for all nodules (2.8% vs. 5.7%, P<0.001), nodules ≤1.0 cm (4.9% vs. 7.3%, P=0.063), nodules >1.0 cm (2.0% vs. 5.0 %, P<0.001), nodules ≤1.5 cm (3.8% vs. 7.9 %, P<0.001), and nodules >1.5 cm (2.1% vs. 3.9 %, P=0.016). The sensitivity of combined FNA/CNB in predicting malignancy was significantly higher than that of CNB (89.0% vs. 80.0%, P<0.001) and FNA (89.0% vs. 58.1%, P<0.001) for all nodules. Within American College of Radiology Thyroid and Imaging Reporting and Data System grades 4-5, in the subgroup of nodules ≤1.5 cm, combined FNA/ CNB showed the best sensitivity in predicting malignancy (91.4%), significantly higher than that of CNB (81.0%, P<0.001) and FNA (57.8%, P<0.001). However, in the subgroup of nodules >1.5 cm, the difference between combined FNA/CNB and CNB was not significant (84.2% vs. 78.9%, P=0.500).

CONCLUSION

Regardless of nodule size, combined FNA/CNB tended to yield lower proportions of inconclusive results than CNB or FNA alone and exhibited higher performance in diagnosing malignancy. The combined FNA/CNB technique may be a more valuable diagnostic method for nodules ≤1.5 cm and nodules with a risk of malignancy than CNB and FNA alone.

Diagnostic performance of six ultrasound-based risk stratification systems in thyroid follicular neoplasm: A retrospective multi-center study

This study aimed to compare the diagnostic performances of six commonly used ultrasound-based risk stratification systems for distinguishing follicular thyroid adenoma (FTA) from follicular thyroid carcinoma (FTC), including the American Thyroid Association Sonographic Pattern System (ATASPS), ultrasound classification systems proposed by American Association of Clinical Endocrinologists, American College of Endocrinology, and Associazione Medici Endocrinology (AACE/ACE/AME), Korean thyroid imaging reporting and data system (K-TIRADS), European Thyroid Association for the imaging reporting and data system (EU-TIRADS), American College of Radiology for the imaging reporting and data system (ACR-TIRADS), and 2020 Chinese Guidelines for Ultrasound Malignancy Risk Stratification of Thyroid Nodules (C-TIRADS). A total of 225 FTA or FTC patients were retrospectively analyzed, involving 251 thyroid nodules diagnosed by postoperative pathological examinations in three centers from January 2013 to October 2021. The diagnostic performances of six ultrasound-based risk stratification systems for distinguishing FTA from FTC were assessed by plotting the receiver operating characteristic (ROC) curves and compared at different cut-off values. A total of 205 (81.67%) cases of FTA and 46 (18.33%) cases of FTC were involved in the present study. Compared with those of FTA, FTC presented more typical ultrasound features of solid component, hypoechoic, irregular margin and sonographic halo (all P<0.001). There were no significant differences in ultrasound features of calcification, shape and comet-tail artifacts between cases of FTA and FTC. There was a significant difference in the category of thyroid nodules assessed by the six ultrasound-based risk stratification systems (P<0.001). The areas under the curve (AUCs) of ATASPS, AACE/ACE/AME, K-TIRADS, EU-TIRADS, ACR-TIRADS and C-TIRADS in distinguishing FTA from FTC were 0.645, 0.729, 0.766, 0.635, 0.783 and 0.798, respectively. Our study demonstrated that all the six ultrasound-based risk stratification systems present potential in the differential diagnosis of FTA and FTC. Specifically, C-TIRADS exerts the best diagnostic performance among the Chinese patients. ATASPS possesses a high sensitivity, while K-TIRADS possesses a high specificity in distinguishing FTA from FTC.

Core Needle Biopsy in Suspicious Malignant Thyroid Nodules with Repeated Nondiagnostic Fine Needle Aspiration

Key message

The clinician could have CNB in mind for thyroid nodules when FNA results were nondiagnostic. Our study would suggest CNB a safe and efficient method for investigating thyroid nodules.

Abstract

Usefulness of preoperative tissue sampling and pathology diagnoses in thyroid tumors were accepted worldwide. We investigate the role of Core needle biopsy (CNB) in the thyroid nodules lesions when FNA results are nondiagnostic. We conducted a cross-sectional study to evaluate twenty-six CNBs results of suspicious malignant thyroid nodules with nondiagnostic repeated fine needle aspiration. 25 from 26 CNBs were diagnostic. Twenty-one needle biopsy reports were papillary thyroid carcinoma, three CNB samples diagnosed medullary thyroid carcinoma and one of them had anaplastic results. All diagnostic needle biopsies results were compatible with final pathology. Our study would suggest CNB a safe and efficient method for investigating thyroid nodules while repeated FNA yielded nondiagnostic results.

Fine Needle Aspiration Cytology vs. Core Needle Biopsy for Thyroid Nodules: A Prospective, Experimental Study Using Surgical Specimen

PURPOSE

To evaluate and compare the diagnostic outcomes of ultrasonography (US)-guided fine needle aspiration (FNA) and core needle biopsy (CNB) performed on the same thyroid nodule using a surgical specimen for direct comparison.

MATERIALS AND METHODS

We included 89 thyroid nodules from 88 patients from February 2015 to January 2016. The inclusion criterion was thyroid nodules measuring ≥ 20 mm (mean size: 40.0 ± 15.3 mm). Immediately after surgical resection, FNA and subsequent CNB were performed on the surgical specimen under US guidance. FNA and CNB cytopathologic results on the specimen were compared with the surgical diagnosis.

RESULTS

Among the 89 nodules, 30 were malignant and 59 were benign. Significantly higher inconclusive rates were seen in FNA for malignant than benign nodules (80.0% vs. 39.0%, p < 0.001). For CNB, conclusive and inconclusive rates did not differ between benign and malignant nodules (p = 0.796). Higher inconclusive rates were seen for FNA among cancers regardless of US features, and in the subgroup of size ≥ 40 mm (62.5% vs. 22.9%, p = 0.028). Eleven cancers were diagnosed with CNB (36.7%, 11/30), while none was diagnosed using FNA.

CONCLUSION

In this experimental study using surgical specimens, CNB showed a potential to provide improved diagnostic sensitivity for thyroid cancer, especially when a conclusive diagnosis is limited with FNA.

Diagnostic efficacy, performance and safety of side-cut core needle biopsy for thyroid nodules: comparison of automated and semi-automated biopsy needles

PURPOSE

This study was performed to compare the utility of the semi-automated and automated side-cut core biopsy needles for thyroid nodules.

METHODS

Between January 2014 and March 2020, biopsy was performed for 278 thyroid nodules using the semi-automated core needle and for 225 nodules using the automated core needle. Nondiagnostic rate, inconclusive rate, diagnostic performance and complication rates were evaluated and compared between two core needle types.

RESULTS

There were 1.2% (6/503) nondiagnostic results and 15.9% (80/503) inconclusive results. Nondiagnostic rate between two needle types was not significantly different. The semi-automated type (33/278, 11.9%) showed lower inconclusive rate than the automated type (47/225, 20.9%) (p = 0.006). The sensitivity, specificity, PPV, NPV and diagnostic accuracy for diagnosis of malignancy of the semi-automated type were 70.18, 100, 100, 84.96 and 88.89%, respectively; the corresponding rates of automated type were 70.45, 100, 100, 86.6, and 89.84%. There were 12 minor complications: four hematomas (4/278, 1.4%) for the semi-automated type and eight hematomas (8/225, 3.6%) for the automated type, which difference was not statistically significant.

CONCLUSION

Core needle biopsy for thyroid nodules using either the semi-automated or automated needle is a safe diagnostic tool. Semi-automated needle has lower inconclusive rate than automated needle.

Diagnostic Performance of Thyroid Core Needle Biopsy Using the Revised Reporting System: Comparison with Fine Needle Aspiration Cytology

BACKGROUND

We aim to validate the diagnostic performance of thyroid core needle biopsy (CNB) for diagnosing malignancy in clinical settings to align with the changes made in recently updated thyroid CNB guidelines.

METHODS

We retrospectively analyzed 1,381 thyroid CNB and 2,223 fine needle aspiration (FNA) samples. The FNA and CNB slides were interpreted according to the Bethesda System for Reporting Thyroid Cytopathology and updated practice guidelines for thyroid CNB, respectively.

RESULTS

Compared to FNA, CNB showed lower rates of inconclusive results categories I (2.8% vs. 11.2%) and III (1.2% vs. 6.2%), and higher rates of categories II (60.9% vs. 50.4%) and IV (17.5% vs. 2.0%). The upper and lower bounds of the risk of malignancy (ROM) for category IV of CNB were 43.2% and 26.6%, respectively. The CNB subcategory IVb with nuclear atypia had a higher ROM than the subcategory without nuclear atypia (40%-62% vs. 23%-36%). In histologically confirmed cases, there was no significant difference in the diagnostic performance between CNB and FNA for malignancy. However, neoplastic diseases were more frequently detected by CNB than by FNA (88.8% vs. 77.6%, P=0.046). In category IV, there was no difference in unnecessary surgery rate between CNB and FNA (4.7% vs. 6.9%, P=0.6361).

CONCLUSION

Thyroid CNB decreased the rate of inconclusive results and showed a higher category IV diagnostic rate than FNA. The revised guidelines for thyroid CNB proved to be an excellent reporting system for assessing thyroid nodules.

Approach to Bethesda system category III thyroid nodules according to US-risk stratification

This study evaluated how to manage Bethesda category III (Bethesda III) (atypia of undetermined significance/follicular lesion of undetermined significance [AUS/FLUS]) thyroid nodules according to the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) to reduce unnecessary surgeries. A total of 161 thyroid nodules diagnosed as Bethesda III underwent surgery from 2016 to 2019. Ultrasonography-guided fine-needle aspiration (US-FNA) or core needle biopsy (CNB) was used for repeat examination. K-TIRADS category was assigned to the thyroid nodules. The proportion of malignancy in Bethesda III nodules confirmed by surgery were significantly increased in proportion relative to K-TIRADS with 60.0% low suspicion, 88.2% intermediate suspicion, and 100% high suspicion nodules (p < 0.001). The proportion of malignancy in AUS and FLUS were significantly different (94.2% vs. 40.0% p = 0.003). The proportion of malignancy in AUS increased with K-TIRADS categories, but there was no difference in FLUS. All K-TIRADS high suspicion nodules were AUS as papillary carcinomas (99%), while 80% of FLUS nodules and 50% of follicular carcinomas showed K-TIRADS low suspicion. In 116 nodules with repeat FNA or CNB after initial Bethesda III results, the conclusive result rate was significantly increased in proportion to K-TIRADS with 58.3% low suspicion, 83.3% intermediate suspicion, and 88.8% high suspicion nodules (p = 0.015). K-TIRADS low suspicion nodules of Bethesda III nodules should be managed after risk-benefit consideration rather than immediate surgery or repeat examination. K-TIRADS for Bethesda III nodules can predict papillary carcinoma well, but not follicular carcinoma.

Comparison of thyroid nodule FNA rates recommended by ACR TI-RADS, Kwak TI-RADS and ATA guidelines

OBJECTIVES

To compare the differences among the thyroid imaging reporting and data system (TI-RADS) proposed by American College of Radiology (ACR TI-RADS), TI-RADS proposed by Kwak (Kwak TI-RADS), and American Thyroid Association (ATA) guidelines in the specificity, sensitivity and the unnecessary FNA rate (the UFR, the false positive rate) of recommended fine needle aspiration (FNA), and to observe the changes of the UFR in the KwakTI-RADS and ATA guidelines with the recommended FNA nodule size threshold.

METHODS

The specificities, sensitivities and UFRs of recommended FNA in the ACR TI-RADS, ATA guidelines and Kwak TI-RADS were calculated and compared. The nodule sizes for recommended FNA of ATA guidelines and Kwak TI-RADS were systematically varied to establish new FNA thresholds. The specificities, sensitivities and UFRs of recommended FNA under the new models were calculated and compared to those in the ACR TI-RADS.

RESULTS

For all thyroid nodules, the UFRs in the ACR TI-RADS, ATA guidelines and Kwak TI-RADS were 26.3%, 47.4% and 40.0%, respectively. The UFR in the ACR TI-RADS was lower than that in the others, and the specificity of recommended FNA in the ACR TI-RADS(73.7%) was higher than that in the others (all P < 0.001), but the sensitivity of recommended FNA in the ACR TI-RADS(89.3%) was lower than that in the others (all P < 0.001). When nodule sizes threshold of the recommended FNA for ATA guidelines Intermediate Suspicion, Low Suspicion, and Very Low Suspicion, and Kwak TI-RADS grade 4b and 4a were gradually increased, the UFRs gradually decreased.

CONCLUSIONS

The UFRs of FNA recommended by the Kwak TI-RADS and ATA guidelines were higher than that of the ACR TI-RADS, and were affected by the recommended FNA nodule size threshold.

Comparison of Core Needle Biopsy and Repeat Fine-Needle Aspiration in Avoiding Diagnostic Surgery for Thyroid Nodules Initially Diagnosed as Atypia/Follicular Lesion of Undetermined Significance

Objective

To compare core needle biopsy (CNB) and repeat fine-needle aspiration (rFNA) to reduce the rate of diagnostic surgery and prevent unnecessary surgery in nodules initially diagnosed as atypia/follicular lesions of undetermined significance (AUS/FLUS).

Materials and Methods

This study included 231 consecutive patients (150 female and 81 male; mean age ± standard deviation, 51.9 ± 11.7 years) with 235 thyroid nodules (≥ 1 cm) initially diagnosed as AUS/FLUS, who later underwent both rFNA and CNB. The nodules that required diagnostic surgery after the biopsy were defined using three different scenarios according to the rFNA and CNB results: criterion 1, surgery for low-risk indeterminate (categories I and III); criterion 2, surgery for high-risk indeterminate (categories IV and V); and criterion 3, surgery for all indeterminate nodules (categories I, III, IV, and V). We compared the expected rates of diagnostic surgery between CNB and rFNA in all 235 nodules using the three surgical criteria. In addition, the expected rates of unnecessary surgery (i.e., surgery for benign pathology) were compared in a subgroup of 182 nodules with available final diagnoses.

Results

CNB showed significantly lower rates of nondiagnostic, AUS/FLUS, and suspicious for malignancy diagnoses (p ≤ 0.016) and higher rates of follicular neoplasm or suspicious for a follicular neoplasm (p < 0.001) and malignant diagnoses (p = 0.031). CNB showed a significantly lower expected rate of diagnostic surgery than rFNA for criterion 1 (29.8% vs. 48.1%, p < 0.001) and criterion 3 (46.4% vs. 55.3%, p = 0.029), and a significantly higher rate for criterion 2 (16.6% vs. 7.2%, p = 0.001). CNB showed a significantly lower expected rate of unnecessary surgery than rFNA for criterion 1 (18.7% vs. 29.7%, p = 0.024).

Conclusion

CNB was superior to rFNA in reducing the rates of potential diagnostic surgery and unnecessary surgery for nodules initially diagnosed as AUS/FLUS in a scenario where nodules with low-risk indeterminate results (categories I and III) would undergo surgery.

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

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

Diagnostic Utility of p62 Expression in Intranuclear Inclusions in Thyroid Core Needle Biopsy Specimens

BACKGROUND/AIM

Core needle biopsy (CNB) has been widely used as an alternative method to ultrasound-guided fine-needle aspiration cytology for histological diagnosis of thyroid specimens. However, nuclear artifactual vacuoles (NuVas) produced during tissue processing can be very difficult and sometimes impossible to distinguish from intranuclear inclusions (NuIns). P62 is an autophagy receptor that recognizes, targets, and eliminates toxic cellular materials during autophagy. Herein, we examined the utility of p62 immunohistochemical staining to detect NuIns in thyroid core needle biopsy specimens.

PATIENTS AND METHODS

Thirty-five thyroid CNB slides from 32 patients and corresponding resection specimens stained with hematoxylin and eosin were reviewed by two pathologists. The immunohistochemical staining pattern of p62 was used to differentiate NuIns from NuVas. The diameter of each nucleus (A) and NuIn (B) was measured, and the number of p62-expressing NuIn-positive (p62In) cells was counted using 1/2 (B/A) and 1/3 (B/A) criteria. The criterion of 1/3 includes NuIns larger than 1/3 and smaller than 1/2 of the nuclear diameter. The criteria of 1/2 includes NuIns larger than 1/2 of the nuclear diameter.

RESULTS

By applying the 1/2 criterion, there were no p62In cells in follicular adenoma (FA) samples. However, in papillary thyroid carcinoma (PTC) samples, 22 of 25 specimens exhibited p62In cells. The sensitivity and specificity to distinguish FA from PTC using the 1/2 criterion were 0.88 and 1.00, respectively. By applying the 1/3 criterion, there was one p62In cell hit in FA samples. However, 23 of 25 PTC specimens showed p62In cells. The sensitivity and specificity to distinguish FA from PTC using the 1/3 criterion were 1.00 and 0.90, respectively.

CONCLUSION

P62 is a useful marker for distinguishing FA and PTC based on CNB specimens. We suggest the 1/2 criteria for identifying p62In cells.

Strategy to reduce unnecessary surgeries in thyroid nodules with cytology of Bethesda category III (AUS/FLUS): a retrospective analysis of 667 patients diagnosed by surgery

PURPOSE

Fine-needle aspiration (FNA) is widely used for the diagnosis of thyroid nodules detected by ultrasonography. However, the cytology of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) often leads to unnecessary thyroid surgery. This study aimed to identify a strategy to reduce unnecessary surgeries in patients with AUS/FLUS nodules.

METHODS

Medical records of 667 patients with the cytology of AUS/FLUS who underwent surgery from January 2007 to December 2017 were retrospectively reviewed. Clinicopathological data were analyzed to identify malignant factors in thyroid nodules with AUS/FLUS. Factors were compared between patients with thyroid cancer and those with benign thyroid nodules, using stepwise multivariate logistic regression and decision tree model.

RESULTS

Pathological thyroid cancer was identified in 193 (43.3%) patients. There was a significant difference in malignancy incidence with respect to family history, number of nodules, number of FNAs, ultrasonographic finding, lymphocytic thyroiditis, and BRAFV600E mutation. Multivariate analysis showed that ultrasonography (K-TIRADS 5) was the most influential independent predictor of malignancy in AUS/FLUS (odds ratio = 11.02, p < 0.001), followed by possessing BRAFV600E mutation (odds ratio = 4.54, p < 0.001). This strategy enabled 226 (89.3%) patients to avoid unnecessary surgeries based on the decision tree model. There was no node of repeated FNA in the decision tree model, which reduced the risk of malignancy (odds ratio = 0.35, p = 0.029).

CONCLUSION

K-TIRADS 5 and BRAFV600E mutation were predictive of malignancy in nodules of AUS/FLUS. These factors should be considered in strategies to reduce unnecessary surgeries for AUS/FLUS.

Usage and Diagnostic Yield of Fine-Needle Aspiration Cytology and Core Needle Biopsy in Thyroid Nodules: A Systematic Review and Meta-Analysis of Literature Published by Korean Authors

Objectives

The usefulness of core needle biopsy (CNB) for the diagnosis of thyroid nodules remains controversial, and preferences vary across hospitals. The purpose of this study was to assess the actual use of CNB in Korea and to analyze the advantages and disadvantages of CNB through a systematic review and meta-analysis of papers published by Korean authors.

Methods

A meta-analysis of full-text publications published in English presenting data from Korea retrieved from the Embase literature database was performed.

Results

CNB led to a significantly lower proportion of non-diagnostic results than fine-needle aspiration (FNA). However, the frequency of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) did not decrease as a result of performing CNB in nodules with initial AUS/FLUS results, while it increased in consecutive cases. A subcategory analysis of AUS/FLUS showed that the increased frequency of AUS/FLUS findings on CNB was due to more frequent diagnoses of architectural atypia and follicular neoplasm, which resulted in a higher frequency of inconclusive findings in consecutive cases compared to FNA. Hospitals favoring CNB had a higher proportion of AUS/FLUS diagnoses. Although the complication rate did not differ significantly between CNB and FNA, serious complications of CNB did occur.

Conclusion

A reduced frequency of non-diagnostic results may be a definite advantage of CNB over FNA. However, the increased frequency of diagnoses of architectural atypia and follicular neoplasm should be considered when selecting CNB as a diagnostic tool.

Is thyroid core needle biopsy a valid compliment to fine-needle aspiration?

Fine-needle aspiration (FNA) has long been considered the first and an important diagnostic tool in the evaluation of thyroid nodules. The advantages of FNA include simplicity, safety, cost-effectiveness, high diagnostic accuracy, and low complication rate. Nevertheless, limitations associated with FNA include a substantial rate of inconclusive results and indeterminate interpretations. Therefore, core needle biopsy (CNB) of the thyroid gland has been proposed as a complementary or even alternate diagnostic method to evaluate thyroid nodules. Although controversial, a growing number of researchers have reported CNB to be an effective and safe sampling method for thyroid nodules, especially for cases with inadequate or indeterminate FNA yields. Skeptics highlight local pain and bleeding risk. Supporters highlight the potential likelihood of overcoming FNA limitations by obtaining a larger amount of tissue and using architecture and cellular details to guide possible ancillary testing. This review evaluates the indications, advantages, and disadvantages of CNB as compared with FNA of the thyroid gland.

Core-Needle Biopsy Does Not Show Superior Diagnostic Performance to Fine-Needle Aspiration for Diagnosing Thyroid Nodules

PURPOSE

To compare the diagnostic performances of fine-needle aspiration (FNA) and core-needle biopsy (CNB) for thyroid nodules according to nodule size.

MATERIALS AND METHODS

This retrospective study included 320 thyroid nodules from 320 patients who underwent both FNA and CNB at outside clinics and proceeded with surgery in our institution between July 2012 and May 2019. According to nodule size, the diagnostic performances of FNA and CNB were calculated using various combinations of test-negatives and test-positives defined by the Bethesda categories and were compared using the generalized estimated equation and the Delong method.

RESULTS

There were 279 malignant nodules in 279 patients and 41 benign nodules in 41 patients. The diagnostic performance of FNA was mostly not different from CNB regardless of nodule size, except for negative predictive value, which was better for FNA than CNB when applying Criteria 1 and 2. When applying Criteria 3, the specificity and positive predictive value of FNA were superior to CNB regardless of size. When applying Criteria 4, diagnostic performance did not differ between FNA and CNB regardless of size. After applying Criteria 5, diagnostic performance did not differ between FNA and CNB in nodules ≥2 cm. However, in nodules ≥1 cm and all nodules, the sensitivity, accuracy, and negative predictive value of CNB were better than those of FNA.

CONCLUSION

CNB did not show superior diagnostic performance to FNA for diagnosing thyroid nodules.

Distribution and malignancy risk of six categories of the pathology reporting system for thyroid core-needle biopsy in 1,216 consecutive thyroid nodules

PURPOSE

The purpose of this study was to present the distribution of lesions among the six categories of the pathology reporting system for thyroid core-needle biopsy (CNB), along with the range of malignancy risk of each category based on different diagnostic criteria for benignity in a clinical cohort.

METHODS

For 1,216 consecutive nodules (≥1 cm) of 1,125 patients who underwent CNB at two hospitals, the diagnostic results based on the six categories of thyroid CNB were analyzed. Patients were divided into three groups according to prior fine-needle aspiration (FNA) status: second-line CNB for nodules where prior FNA yielded nondiagnostic or unsatisfactory results (n=57), second-line CNB for nodules with prior FNA results of atypia/follicular lesion of undetermined significance (AUS/FLUS) (n=303), and first-line CNB (n=856).

RESULTS

The proportion of nodules in each CNB category and the range of the malignancy rate for each category was as follows, in order from category I to VI: 1.8%, 23.1%-75.0%; 57.9%, 0.7%-16.7%; 16.0%, 13.2%-46.7%; 8.8%, 53.8%-56.8%; 2.0%, 100%; and 13.5%, 100%. First-line CNB was associated with a higher rate of conclusive diagnoses (category II, IV, or VI) (725 of 856, 84.7%) than second-line CNB with prior nondiagnostic or AUS/FLUS FNA results (241 of 360, 66.9%; P<0.001).

CONCLUSION

The overall distribution of nodules across the six categories of thyroid CNB and the ranges of malignancy risk for those categories were presented in a clinical cohort. First-line CNB tended to produce a higher rate of conclusive results than second-line CNB with prior inconclusive FNA results.

Comparison of Diagnostic Accuracy of Thyroid Cancer With Ultrasound-Guided Fine-Needle Aspiration and Core-Needle Biopsy: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to evaluate the accuracy of fine-needle aspiration (FNA) and core-needle biopsy (CNB) in diagnosing thyroid cancer. The PubMed, Embase, and Cochrane Library databases were retrieved up to May 2019, and the overall accuracy of FNA and CNB in diagnosing thyroid cancer was evaluated by meta-analysis. The sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were calculated. The summary receiver operating characteristic (ROC) curve was estimated, and the area under the ROC curve (AUC) was calculated. Ten eligible studies, involving 10,078 patients with 10,842 thyroid nodules, were included. The overall sensitivity and specificity of FNA and CNB for thyroid cancer were 0.72 [95 % confidence interval (CI): 0.69-0.74], 0.99 (95% CI: 0.98-0.99), and 0.83 (95% CI: 0.81-0.85), 0.99 (95% CI: 0.98-0.99), respectively. Other parameters used to assess efficacy included PLR 41.71 (2.15-808.27) and 51.56 (3.20-841.47), NLR 0.31 (0.22-0.42) and 0.22 (0.15-0.32), for FNA and CNB, respectively. Overall, the pooled summary ROC (AUC) value of FNA and CNB was 0.9025 and 0.7926, respectively. No significant difference was observed between the two AUCs of FNA and CNB (P = 0.164). FNA and CNB are still similar as first-line diagnostic tools. FNA remains a good first-line method for detecting thyroid malignancies.

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.

Validation of molecular biomarkers for preoperative diagnostics of human papillary thyroid carcinoma in fine needle aspirates

Background

Despite substantial efforts, reliable preoperative diagnostic for human thyroid malignancies in case of cytologically indeterminate nodules is still missing, resulting in high number of unnecessary thyroidectomies. In an attempt to increase precision of existing preoperative diagnostics, we aimed at validating the panel of molecular biomarkers predictive for papillary thyroid carcinoma (PTC) in preoperative fine needle aspirate (FNA) samples.

Methods

In this prospective study conducted in preoperative thyroid FNA from 44 thyroid nodules, expression levels of 11 molecular biomarkers previously validated on the postoperative samples of PTCs were measured by Cell-to-CT and QuantiGene Plex methods and correlated with final diagnosis.

Results

The QuantiGene Plex resulted in reliable gene expression measurements for FNA and core-needle biopsy (CNB) samples, however this method was less sensitive than pre-amplification based Cell-to-CT. Measurements conducted on the same samples by the two methods significantly correlated for most of the genes. Expression levels of TIMP1, c-MET and ARNTL were upregulated in PTC nodules as compared to benign counterparts, supporting previous post-operative studies. Strong correlation was observed between these biomarker alterations in the same samples. Within the sub-group of 15 indeterminate nodules (Bethesda II-V), TIMP1 had 100% specificity and 83% sensitivity for PTC cases.

Conclusions

Assessment of TIMP1, c-MET and core-clock gene ARNTL expression levels by QuantiGene Plex assay in FNA samples holds promise as an ancillary method to the cytological preoperative diagnostics.

Validation of web-based thyroid imaging reporting and data system in atypia or follicular lesion of undetermined significance thyroid nodules

BACKGROUND

Atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) show variable malignancy risk. We validated the web-based predictive models and the scoring system by the American College of Radiology (ACR) for AUS/FLUS nodules to stratify the malignancy risk.

METHODS

From January 2011 to November 2014, 275 consecutive nodules diagnosed as AUS/FLUS were enrolled. The discrimination and calibration ability of a web-based scoring with inclusion of biopsy result and sonographic features, old web-based scoring model without biopsy result, and ACR models were assessed.

RESULTS

The areas under the receiver operating characteristic curve of the validation set were 0.670 for the new web-based model, 0.710 for the old web-based model, and 0.732 for the ACR scoring risk-stratification model. All models were well calibrated.

CONCLUSION

The web-based scoring risk-stratification model using the combined information of ultrasonography features and biopsy result for AUS/FLUS nodules to stratify malignancy risk presents an acceptable predictive accuracy.

Fine needle aspiration biopsy indications for thyroid nodules: compare a point-based risk stratification system with a pattern-based risk stratification system

OBJECTIVES

We aim to compare the diagnostic performance to assess thyroid nodules and reliability for recommending fine needle aspiration biopsy (FNAB) between American College of Radiology thyroid image reporting and data system (ACR TI-RADS) and American Thyroid Association (ATA) guidelines.

METHODS

In total, this retrospective study included 1001 consecutive thyroid nodules in 918 patients from May 2016 to December 2017. US features of the thyroid nodules, including composition, echogenicity, shape, margins, echogenic foci, and size, were reviewed and were classified according to ACR TI-RADS and ATA guidelines, respectively. The diagnostic performance to assess thyroid nodules and reliability for recommending fine needle aspiration biopsy were compared between ACR TI-RADS and ATA guidelines.

RESULTS

Of the 1001 thyroid nodules, 609 (60.8%) were benign and 392 (39.2%) were malignant. The sensitivity, specificity, PPV, NPV, and accuracy were 96.7%, 77.3%, 73.3%, 97.3%, and 84.9%, respectively, for ACR TI-RADS and 99.2%, 16.1%, 43.2%, 97.0%, and 48.7%, respectively, for ATA guidelines. AUC of ACR TI-RADS was significantly greater than ATA guidelines (0.935 (0.918, 0.949) vs 0.884 (0.862, 0.903), p < 0.001). Biopsy yield of malignancy, biopsy rate of malignancy, and unnecessary FNAB rate were 59.5%, 91.3%, and 40.5%, respectively, for ACR TI-RDS and 38.5%, 97.4%, and 61.5%, respectively, for ATA guidelines.

CONCLUSIONS

ACR TI-RADS was more accurate than ATA guidelines for differentiating malignant thyroid nodules from benign nodules and more reliable than ATA guidelines for recommending thyroid nodules for FNAB.

KEY POINTS

• Malignant risk of thyroid nodules can be stratified by ultrasound. • American College of Radiology guidelines were more accurate for differentiating malignant thyroid nodules from benign nodules. • American College of Radiology guidelines were more reliable for recommending thyroid nodules for biopsy.

Tumor Growth Rate Does Not Predict Malignancy in Surgically Resected Thyroid Nodules Classified as Bethesda Category III with Architectural Atypia

BACKGROUND

It is unknown whether the growth of thyroid nodules with a Bethesda category III cytology (atypia of undetermined significance [AUS]) is predictive of malignancy, especially in cases with architectural atypia (AUS-A). This study evaluated whether tumor growth rates can help distinguish malignant from benign nodules in the AUS-A subcategory.

METHODS

This retrospective, single-center cohort study included 172 patients who underwent diagnostic thyroid surgery because of a nodule with a cytological diagnosis of AUS-A. The growth kinetics of nodules was assessed by serial preoperative neck ultrasonography over a median follow-up of 52.6 months (range 12.7-198.3 months).

RESULTS

Pathologic examinations showed that 112 (65%) and 60 (35%) patients had benign and malignant nodules, respectively. The largest diameter and volume of both benign and malignant nodules increased gradually (p < 0.001). However, there was no significant difference in the growth rates of benign and malignant nodules based on the largest diameter (p = 0.132) and volume (p = 0.200). The time to tumor growth curves and estimated median time to significant tumor growth from baseline were not significantly different in malignant nodules compared to benign nodules (p = 0.458 and p = 0.568, respectively). The relative risk (RR) of malignancy of growing and stable nodules did not differ significantly based on the largest diameter (RR = 0.5; p = 0.064) and volume (RR = 0.9; p = 0.748).

CONCLUSIONS

The size of thyroid nodules classified as AUS-A increased linearly, regardless whether these nodules were benign or malignant. These results suggest that growth kinetics on serial preoperative neck ultrasonography cannot predict malignancy in the AUS-A subcategory.

Role of Immunohistochemistry in Fine Needle Aspiration and Core Needle Biopsy of Thyroid Nodules

Objectives

Immunohistochemistry (IHC) has been used for the diagnosis of indeterminate results in fine needle aspiration (FNA) of thyroid nodules. However, the role of IHC in core needle biopsy (CNB) is not clear and the efficacy of testing for molecular markers following CNB has not been evaluated. The aim of this study is to compare the role of IHC staining in CNB with that in FNA when examining thyroid nodules and to compare the sensitivity and usefulness of different molecular markers.

Methods

Consecutive cases of thyroid FNA and CNB accompanied by IHC from 2004 to 2014 were included in this study with retrospective review of medical record. The rate of remaining nondiagnostic result (unsatisfactory, atypia of undetermined significance or follicular lesion of undetermined significance [AUS/FLUS]) and rate of strong expression of each molecular marker according to the diagnosis were evaluated.

Results

IHC was more frequently performed in CNB with multiple molecular markers compared to FNA (38.1% vs. 2.8%, 3 or 4 markers [Gal-3, HBME-1, CK19, and CD56] vs. 1 marker [Gal-3]). In the CNB group, 11.3% remained as AUS/FLUS after IHC, and the rate remaining nondiagnostic was significantly less than in the FNA group (42.9%). Gal-3 and CK19 showed higher specificity and expressed mainly in conventional type of papillary carcinoma and HBME-1 showed higher sensitivity for the diagnosis of carcinoma with expression in both conventional type and follicular variant papillary thyroid carcinoma.

Conclusion

With these data, we could conclude that IHC was more effective following CNB than following FNA.

Web-based thyroid imaging reporting and data system: Malignancy risk of atypia of undetermined significance or follicular lesion of undetermined significance thyroid nodules calculated by a combination of ultrasonography features and biopsy results

BACKGROUND

The purpose of this study was to construct a web-based predictive model using ultrasound characteristics and subcategorized biopsy results for thyroid nodules of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) to stratify the risk of malignancy.

METHODS

Data included 672 thyroid nodules from 656 patients from a historical cohort. We analyzed ultrasound images of thyroid nodules and biopsy results according to nuclear atypia and architectural atypia. Multivariate logistic regression analysis was performed to predict whether nodules were diagnosed as malignant or benign.

RESULTS

The ultrasound features, including spiculated margin, marked hypoechogenicity, calcifications, biopsy results, and cytologic atypia, showed significant differences between groups. A 13-point risk scoring system was developed, and the area under the curve (AUC) of the receiver operating characteristic (ROC) curve of the development and validation sets were 0.837 and 0.830, respectively (http://www.gap.kr/thyroidnodule_b3.php).

CONCLUSION

We devised a web-based predictive model using the combined information of ultrasound characteristics and biopsy results for AUS/FLUS thyroid nodules to stratify the malignant risk.

Statement and Recommendations on Interventional Ultrasound as a Thyroid Diagnostic and Treatment Procedure

The recently published guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) on interventional ultrasound (INVUS)-guided procedures summarize the intended interdisciplinary and multiprofessional approach. Herewith, we report on recommendations for interventional procedures for diagnosis and treatment of the thyroid gland.

Recent Advances in Core Needle Biopsy for Thyroid Nodules

Core needle biopsy (CNB) was introduced as an alternative diagnostic tool to fine-needle aspiration (FNA), and is increasingly being used in the preoperative assessment of thyroid nodules. CNB provides a definitive diagnosis in most cases, but it sometimes may be inconclusive. CNB has the advantage of enabling a histologic examination in relation to the surrounding thyroid tissue, immunohistochemistry, and molecular testing that can provide a more accurate assessment than FNA in selected cases. Nevertheless, CNB should be performed only by experienced experts in thyroid interventions to prevent complications because CNB needles are larger in caliber than FNA needles. As recent evidence has accumulated, and with improvements in the technique and devices for thyroid CNB, the Korean Society of Thyroid Radiology released its 2016 thyroid CNB guidelines and the Korean Endocrine Pathology Thyroid Core Needle Biopsy Study Group published a consensus statement on the pathology reporting system for thyroid CNB in 2015. This review presents the current consensus and recommendations regarding thyroid CNB, focusing on indications, complications, and pathologic classification and reporting.

Comparison of Core-Needle Biopsy and Fine-Needle Aspiration for Evaluating Thyroid Incidentalomas Detected by 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: A Propensity Score Analysis

BACKGROUND

This study used a propensity score analysis to assess the roles of core-needle biopsy (CNB) and fine-needle aspiration (FNA) in the evaluation of thyroid incidentalomas detected on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT).

METHODS

The study population was obtained from a historical cohort who underwent ¹⁸F-FDG PET/CT between October 2008 and September 2015. Patients were included who underwent ultrasound-guided CNB or FNA for incidental focal uptake of ¹⁸F-FDG in the thyroid gland on PET/CT. The primary study outcomes included the inconclusive result rates in the CNB and FNA groups. The secondary outcome measures included the non-diagnostic result rate and the diagnostic performance for neoplasms. Multivariate analysis, propensity score matching, and inverse probability weighting were conducted.

RESULTS

A total of 1360 nodules from 1338 patients were included in this study: 859 nodules from 850 patients underwent FNA, and 501 nodules from 488 patients underwent CNB. Compared to FNA, CNB demonstrated a significantly lower inconclusive result rate in the pooled cohort (23.8% vs. 35.4%; p < 0.001), propensity score-matched cohorts (22.9% vs. 36.6%; p < 0.001), and with inverse probability weighting (22.4% vs. 35.2%; p < 0.001). Non-diagnostic result rates were also significantly lower in CNB than in FNA. The diagnostic performance of the two groups in the pooled and matched cohorts was similar, with no significant differences found.

CONCLUSIONS

The significantly lower inconclusive result rates in CNB than in FNA were consistent within the propensity score-matched cohorts. Therefore, CNB appears to be a promising diagnostic tool for patients with thyroid incidentalomas detected on ¹⁸F-FDG PET/CT.