Ultrasound guidance improves the adequacy of our preoperative thyroid cytology but not its accuracy

Comparison of the collection approaches of 2 large thyroid fine-needle aspiration practices reveals differing advantages for cytology and molecular testing adequacy rates

INTRODUCTION

At our institution, almost all thyroid fine-needle aspiration (FNA) procedures are performed by either Endocrinology or Radiology personnel. In this study, we compared the cytology and molecular adequacy rates of these 2 thyroid FNA practices, which differ on several aspects of specimen procurement.

MATERIALS AND METHODS

All thyroid FNA specimens from Endocrinology and Radiology practices between September 2008 and December 2016 were included. Over this time frame, the molecular testing modality transitioned from polymerase chain reaction (PCR)-based (7-gene panel era) to next generation sequencing (NGS)-based (ThyroSeq era). In measuring cytology adequacy, the Bethesda System unsatisfactory rate was determined. Molecular adequacy was categorized as Optimal, Limited Thyroid Epithelial Cells, Limited Nucleic Acids, or Failed. These parameters were compared for the 2 practices.

RESULTS

The study cohorts comprised 5810 specimens from Endocrinology and 4597 from Radiology. More Endocrinology specimens were satisfactory for cytology diagnosis than those from Radiology (94.7% versus 90.0%, P < 0.001). For molecular adequacy, fewer Endocrinology specimens were optimal than specimens from Radiology for both the 7-gene panel era (76.2% versus 82.9%, P < 0.001) and the ThyroSeq era (88.1% versus 91.9%, P = 0.049).

CONCLUSIONS

The 2 thyroid FNA practices varied inversely in their adequacy rates for cytology and molecular testing. Had one practice been superior for both cytology and molecular adequacy, a recommendation for the method of choice would have been straightforward. However, our results show that optimization of FNA practice for the current practice of thyroid cytology requires further investigation due to the complex nature of specimen procurement.

Comparison of 1869 thyroid ultrasound-guided fine-needle aspiration biopsies between general surgeons and interventional radiologists

BACKGROUND

Thyroid nodules are commonly encountered problems in clinical practice. For patients who have a thyroid nodule, the fine-needle aspiration biopsy (FNAB) is the most important test, as it is the most reliable diagnostic method for distinguishing between benign thyroid nodules and cancerous nodules. FNAB is able to be performed either via an ultrasound (USG) or alone and is the first choice when it comes to diagnosing thyroid nodules, given that it is cheap, safe and provides accurate results.

OBJECTIVE

In this study-a retrospective analysis of FNAB via USG - our aim is to evaluate the multiple variables related to FNAB procedures, including the experience of the person performing the biopsy, the age and gender of the patient, the number of nodules, the size of the nodule(s) and the number of lams recorded from the cytopathology report on non-diagnostic rates, conducted at an invasive radiology clinic and at a general surgery clinic.

MATERIALS AND METHODS

A total of 1062 patients involving 1869 nodules, examined using FNAB via USG, were reviewed retrospectively from records dated between November 2011 and July 2014 and from pathology reports taken from the ANEAH General Surgery clinic and Interventional Radiology clinic. Cytopathology results were classified according to the 2007 Bethesda System for Reporting. Gender, age, number of nodules, diameter of the nodules, biopsied nodules, location of the nodules, number of lams, symptoms and the date of biopsies were the parameters used to examine the factors involved in non-diagnostic cytopathology invasive radiology. These parameters were inspected at both of the clinics (ANEAH General Surgery clinic and Interventional Radiology clinic). In analyzing the results, the statistical significance level was set at 0.05, where in cases that the p value was under 0.05 (p < 0.05), it was determined that no significant relationship existed. In this study, data were analyzed using SPSS 20 software.

RESULTS

Of the nodules reviewed, 1620 were found on females and 249 on males. The age of the patients ranged from 10 to 87 years, with the mean age being 50 years. In the general surgery clinic, 470 nodules of 341 patients were aspirated, and in the interventional radiological clinic, 1399 nodules of 721 patients were aspirated. In the literature review conducted to compare statistical assessments of FNAB via USG, no significant difference was found between the ANEAH General Surgery clinic and the Invasive Radiology clinic (p > 0.05). In the invasive radiology clinic, non-diagnostic rates decreased with the increase in experience of the person who conducted the biopsy (p = 0.001).

CONCLUSION

The results from both of the clinic's rates of non-diagnostic FNAB, performed via USG, were found to be acceptable. Our study also demonstrates that USG-guided FNAB can be performed with a low non-diagnostic rate as experience grows.

Cytopathologists can reliably perform ultrasound-guided thyroid fine needle aspiration: a 1-year audit on 3715 consecutive cases

OBJECTIVE

In our Pathology Department, fine needle aspiration (FNA) of palpable thyroid nodules is performed by cytopathologists who ensure correct sample management and rapid on-site evaluation (ROSE). Conversely, ultrasound (US)-guided FNAs have traditionally been carried out by endocrinologists and radiologists in outside clinics, where the presence of a cytopathologist is not always feasible. To overcome this limitation, cytopathologists have started to perform US-guided FNAs themselves. This study retrospectively evaluates 1 year of this novel practice.

METHODS

A total of 2225 US-guided FNAs were performed in our clinic by cytopathologists, whereas 1490 aspirates were taken by a group of non-cytopathologists. Among these, 756 FNAs were taken by a single experienced endocrinologist. The distribution of the Bethesda classification categories was evaluated in each of these groups.

RESULTS

FNAs performed by cytopathologists were more often diagnostic and better prepared than those taken by non-cytopathologists, including those taken by the experienced endocrinologist (P < 0.01). The latter operator yielded a higher rate of suspicious and malignant FNAs, reflecting a more appropriate clinical triage of worrisome nodules.

CONCLUSION

Although the endocrinologist's evaluation is crucial to select clinically relevant thyroid nodules, cytopathologists can reliably perform US guidance in addition to their traditional expertise in sampling, specimen preparation and ROSE.

Rapid on-site evaluation of fine needle aspiration specimens by cytology scientists: a review of 3032 specimens

OBJECTIVES

To determine: (1) the accuracy of cytology scientists at assessing specimen adequacy by rapid on-site evaluation (ROSE) at fine needle aspiration (FNA) cytology collections; and (2) whether thyroid FNA with ROSE has lower inadequacy rates than non-attended FNAs.

METHODS

The ROSE of adequacy for 3032 specimens from 17 anatomical sites collected over a 20-month period was compared with the final report assessment of adequacy. ROSE was performed by 19 cytology scientists. The report profile for 1545 thyroid nodules with ROSE was compared with that for 1536 consecutive non-ROSE thyroid FNAs reported by the same cytopathologists during the study period.

RESULTS

ROSE was adequate in 75% (2276/3032), inadequate in 12% (366/3032) and in 13% (390/3032) no opinion was rendered. Of the 2276 cases assessed as adequate by ROSE, 2268 (99.6%) were finally reported as adequate for assessment; eight specimens had adequacy downgraded on the final report. Fifty eight per cent of cases with a ROSE assessment of inadequate were reported as adequate (212/366), whereas 93% (363/390) with no opinion rendered were reported as adequate. The overall final report adequacy rate for the 3032 specimens was 94% (2843/3032). Confirmation of a ROSE of adequacy at reporting was uniformly high amongst the 19 scientists, ranging from 98% to 100%. The inadequacy rate for thyroid FNAs with ROSE (6%) was significantly (P < 0.0001) lower than for non-ROSE thyroid FNAs (17%). A significantly (P = 0.02) higher proportion of adequate ROSE thyroid specimens was reported with abnormalities, compared with non-ROSE thyroid collections.

CONCLUSIONS

Cytology scientists are highly accurate at determining specimen adequacy at ROSE for a wide range of body sites. ROSE of thyroid FNAs can significantly reduce inadequate reports.

Does elastography reduce the need for thyroid FNAs?

OBJECTIVE

Ultrasound elastography (USE) assesses lesion stiffness by evaluating tissue distortion in response to stress; it is emerging as a potentially useful tool to augment the ultrasound characterisation of thyroid nodules. The aim of this study was to assess the accuracy of USE examination of thyroid nodules compared with pathological outcome, especially to determine whether USE could reliably detect benign nodules and reduce the numbers of ultrasound guided fine needle aspiration cytology (USgFNAC).

DESIGN

Over a three-year period, thyroid nodules were initially characterised by B-mode ultrasound (US) findings. Where USgFNAC was indicated by clinical concern and/or the sonographic appearances, the lesion was then subjected to USE by an experienced operator prior to the USgFNAC.

PATIENTS

147 thyroid nodules were examined by USE and USgFNAC in 146 patients.

MEASUREMENTS

The elastographic appearance was subjectively categorized at the time of the examination (soft, intermediate or hard) and subsequently compared with the cytological/histological outcome.

RESULTS

A total of 122 nodules were non-neoplastic, 5 nodules were benign neoplasms, 10 nodules had indeterminate cytology and 10 were malignant neoplasms. The sensitivity of USE for malignancy was 90.0%, specificity was 79.6%, PPV was 24.3%, NPV was 99.1% and accuracy was 80.3%.

CONCLUSION

Thyroid nodules that are soft at USE have a high likelihood of being non-neoplastic and subjective USE assessment of thyroid nodules by an experienced operator can be a useful means of avoiding USgFNAC for benign nodules. In contrast, we suggest that all nodules that are intermediate or hard on USE undergo USgFNAC.

Comparative study of thyroid puncture biopsy guided by contrast-enhanced ultrasonography and conventional ultrasound

The aim of this study was to investigate the application value of thyroid puncture biopsy guided by contrast-enhanced ultrasound (CEUS). A total of 48 patients with 51 solid thyroid nodules (suspected papillary thyroid carcinoma, PTC) were enrolled in the study. Following detection by conventional ultrasonography and CEUS, puncture biopsy of the suspicious lesions guided by conventional ultrasonography and CEUS was conducted, respectively. Then, pathological diagnosis was performed. The number of PTC positive nodules and puncture points detected by the two methods were compared. In 51 nodules with 310 punctures, 44 nodules (86.3%, 44/51) and 240 punctures (77.4%, 240/310) were pathologically diagnosed as PTC. In the 44 nodules diagnosed as PTC, 43 and 34 nodules were detected by CEUS and conventional ultrasound, respectively, with a significant difference between the two methods (P=0.022). Eleven (25%) nodules were independently detected by CEUS. The sensitivity and accuracy of puncture point detection by CEUS (82.9 and 82.6%, respectively) were significantly higher compared with those of conventional ultra-sound (48.3 and 56.5%, respectively; P<0.001). The specificity of puncture points detected by CEUS (81.4%) was significantly lower compared with that by conventional ultrasound (84.3%; P=0.009). Compared with conventional ultrasound, a greater number of PTC-positive nodules were detected by CEUS, with increased sensitivity and accuracy of the puncture points.

Diagnostic adequacy of surgeon-performed ultrasound-guided fine needle aspiration biopsy of thyroid nodules

BACKGROUND

Surgeon-performed ultrasonography (US) of thyroid nodules might serve as a potential therapeutic guide to designate accurate surgical or clinical intervention.

OBJECTIVE

To evaluate the diagnostic adequacy of surgeon-performed ultrasonography guided fine needle aspiration biopsy (FNAB) of thyroid nodules, the factors responsible for diagnostic adequacy and the impact of surgeon-performed US on treatment approach.

METHODS

Retrospective review of a single surgeon performed 621 US-guided FNABs without on-site cytological specimen assessment. Outside US findings were compared to the surgeon-performed US. Measured variables and outcomes for the study included diagnostic adequacy rates and the effects of detected differences between US reports on treatment variability.

RESULTS

Diagnostic adequacy rate of surgeon-performed US-guided FNAB was determined to be 94.52% without on-site specimen evaluation by cytologist. Non-diagnostic specimens occurred in 34 of 621 (5.48%) nodules. The differences detected between the outside US and surgeon-performed US altered invasive treatment algorithm in 30 (5.47%) patients. FNAB was avoided for 15 (2.7%) patients. Total thyroidectomy became the preferred surgical option in 15 (2.7%) patients after the discovery of additional nodules in the contralateral lobe.

CONCLUSION

Surgeon-performed US offers clear clinical benefits in terms of diagnostic yield of FNAB with providing valuable additional data that might alter surgical treatment approach.

How to interpret thyroid biopsy results: a three-year retrospective interventional radiology experience

Results of thyroid biopsy determine whether thyroid nodule resection is appropriate and the extent of thyroid surgery. At our institution we use 20/22-gauge core biopsy (CBx) in conjunction with fine-needle aspiration (FNA) to decrease the number of passes and improve adequacy. Occasionally, both ultrasound (US)-guided FNA and CBx yield unsatisfactory specimens. To justify clinical recommendations for these unsatisfactory thyroid biopsies, we compare rates of malignancy at surgical resection for unsatisfactory biopsy results against definitive biopsy results. We retrospectively reviewed a database of 1979 patients who had a total of 2677 FNA and 663 CBx performed by experienced interventional radiologists under US guidance from 2003 to 2006 at a tertiary-care academic center. In 451 patients who had surgery following biopsy, Fisher's exact test was used to compare surgical malignancy rates between unsatisfactory and malignant biopsy cohorts as well as between unsatisfactory and benign biopsy cohorts. We defined statistical significance at P = 0.05. We reported an overall unsatisfactory thyroid biopsy rate of 3.7% (100/2677). A statistically significant higher rate of surgically proven malignancies was found in malignant biopsy patients compared to unsatisfactory biopsy patients (P = 0.0001). The incidence of surgically proven malignancy in unsatisfactory biopsy patients was not significantly different from that in benign biopsy patients (P = 0.8625). In conclusion, an extremely low incidence of malignancy was associated with both benign and unsatisfactory thyroid biopsy results. The difference in incidence between these two groups was not statistically significant. Therefore, patients with unsatisfactory biopsy specimens can be reassured and counseled accordingly.

Quality improvement by standardization of procurement and processing of thyroid fine-needle aspirates in the absence of on-site cytological evaluation

BACKGROUND

Thyroid nodules are relatively common and are routinely evaluated by fine-needle aspiration cytology, usually performed by clinicians. We noticed qualitative and/or quantitative variability in samples submitted to the cytopathology laboratory from clinicians, for example, the number of glass slides submitted (2-25) and air-dried smears versus alcohol-fixed slides, with variability in specimen adequacy and interpretability. The objective of this study was to standardize the preanalytic variables to determine if there is an improvement in the specimen quality.

METHODS

We standardized the method of collection (ultrasound-guided, 25-gauge needle, four passes) and preparation of samples (four total smears: two air-dried, two fixed, with liquid-based preparation and/or cell block) and personnel involved.

RESULTS

Standardization of thyroid nodule fine-needle aspiration and sample preparation by clinical staff resulted in an overall improvement in the quality of sample (odds ratio = 3.82, 95% confidence interval 2.02-7.24, p < 0.0001) with an increased proportion of satisfactory samples from 67% prestandardization to 89% poststandardization.

CONCLUSIONS

Standardization resulted in a significant improvement in specimen interpretability.

Thyroid fine-needle aspiration biopsy: variability in reporting

BACKGROUND

The low incidence of thyroid cancer despite the high prevalence of thyroid nodules necessitates a screening tool to determine which patients require surgical management. The utility of fine-needle aspiration biopsy (FNAB) for this purpose requires a low false-negative (FN) rate and an acceptable sensitivity and specificity for the detection of malignancy. While reviewing our institution's experience with thyroid FNAB, we found significant discrepancies in how statistics of thyroid FNAB were tabulated and reported in the literature. Here we examine the sources of these discrepancies by evaluating large series of thyroid FNAB with regard to cytopathologic reporting and statistical calculation.

METHODS

Published series of thyroid FNAB with >200 FNAB and available histological data with sufficient raw data to recalculate statistics were analyzed. Considering indeterminate and malignant results to be positive FNAB results, since, in a four-tier system, both lead to surgical management, specificity, sensitivity, accuracy, positive predictive value, negative predictive value, FN, and false-positive (FP) rates were recalculated. Differences between reported and recalculated statistics were then evaluated for significance.

RESULTS

Nineteen studies and 20 series were identified. The following are reported and recalculated means, respectively: for sensitivity, 81% and 86%; for specificity, 81% and 62%; for accuracy, 77% and 71%; for positive predictive value, 65% and 50%; for negative predictive value, 84% and 93%; for FN rates, 13% and 14%; for FP rates, 10% and 38%. FP rates had a mean of 1.4% when recalculated considering only malignant FNAB as positive tests. Specificity and FP rates had statistically significant differences between the means of reported and recalculated values.

CONCLUSIONS

Thyroid FNAB remains the screening tool of choice in the evaluation of thyroid nodules. However, the variability in the calculation of reported thyroid FNAB statistics highlights the need for uniformity in statistical reporting for accurate understanding of thyroid FNAB's clinical utility.

Thin core needle biopsy crush preparations in conjunction with fine-needle aspiration for the evaluation of thyroid nodules: a complementary approach

BACKGROUND

Fine-needle aspiration (FNA) is widely accepted as the initial test to evaluate thyroid nodules; however, inadequate and suboptimal specimens have been 1 of its limitations. Unsatisfactory rates of 4.1% to 43% have been reported, but suboptimal specimens with adequate epithelial cells and other limiting factors, such as clotting, often are not addressed. The authors' institution has a low unsatisfactory rate, especially for thyroid biopsies performed under ultrasound in the Interventional Radiology (IR) Department. In addition to on-site evaluation for all cases, they concomitantly use thin, 22/20-gauge core needle biopsy (CB) crush preparations (CP) for unsatisfactory/suboptimal FNAs. The CB usually is done after 2 FNA passes and, in most cases, is exhausted by making an air-dried CP, which is evaluated on site for adequacy; any residual tissue is processed for tissue sections. Experience is required to interpret CP on air-dried smears. In this report, the authors describe a complementary approach to thyroid biopsy that has worked well.

METHODS

All thyroid FNA and CB/CP that were performed in the IR Department during the year 2005 were reviewed. Follow-up histology and records of all procedural complications were retrieved.

RESULTS

Seven hundred thirteen thyroid biopsies qualified, 225 biopsies (31%) had FNA with CB/CP (85% had only CP for evaluation), and 488 biopsies (69%) had only FNA. The final unsatisfactory rate in IR for FNA was 8.7%; this was reduced to 3.4% with the use of CB/CP. The addition of CB also helped to obtain a more definitive diagnosis in suboptimal FNA specimens. Cytologic-histologic correlation was comparable for FNA only cases and FNA/CB cases. There were no significant procedural complications in CB cases.

CONCLUSIONS

FNA in conjunction with a thin CB/CP performed during the same procedure is a safe technique that can reduce the rate of unsatisfactory and suboptimal thyroid biopsy.

The clinical and diagnostic impact of using standard criteria of adequacy assessment and diagnostic terminology on thyroid nodule fine needle aspiration

The study was aimed to investigate the impact of using standard criteria for assessing specimen adequacy and diagnostic terminology (CAST) on fine-needle aspiration (FNA) diagnosis and clinical management of thyroid nodules. The study included similar numbers of FNAs performed in 2 year before (group A) and 1.5 year after (group B) implementing the standard CAST. In comparison to group A, group B showed a significantly lower rate of nondiagnostic specimens (RND) (16.1% vs. 21.6%, P <or= 0.01) and rate of descriptive diagnoses (RDD) (3.8% vs. 14.5%, P <or= 0.001) and greater non-neoplastic (70.0% vs. 64.1%, P<0.05) and follicular cell lesions (7.4% vs. 4.3%, P<0.05) but a similar percentage of neoplastic diagnoses. The rate of surgical follow-up (RSF) was significantly higher in group B than in group A, overall (21.6% vs. 17.0%, P<0.05), or in subgroups of non-neoplastic (12.6% vs. 5.4%, P<0.01) and neoplastic categories (81.0% vs. 61.0%, P<0.05). The rate of cytohistologic concordance was higher in group B although the difference was not statistically significant. We concluded that use of the standard CAST on FNA diagnosis of thyroid nodules significantly reduced RND and RDD, providing more consistent diagnoses among the pathologists as well as better and more uniform communication between the pathologists and the clinicians. Furthermore, the cytohistological concordance was slightly better after CAST implementation, indicating that the improvement of diagnostic consistency among pathologists did not sacrifice the diagnostic accuracy.

The preoperative exclusion of thyroid carcinoma in multinodular goiter: Dynamic contrast-enhanced magnetic resonance imaging versus ultrasonography-guided fine-needle aspiration biopsy

BACKGROUND

We compared the diagnostic values of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and ultrasonography (USG)-guided fine-needle aspiration biopsy (FNAB) in the detection of thyroid carcinoma associated with multinodular goiter.

METHODS

USG-guided FNAB and DCE-MRI were performed consecutively on 26 patients who had multinodular goiter with dominant nodules and clinical suspicion of malignancy. DCE-MRI findings, cytodiagnosis, and final histopathologic results were correlated. We compared the sensitivity, specificity, diagnostic accuracy, and positive (PPV) and negative predictive values (NPV) of DCE-MRI and USG-guided FNAB.

RESULTS

Of 57 nodules in 26 patients, 16, 37, and 4 nodules showed delayed, plateau, and rapid washout patterns, respectively. Thyroid carcinoma was found in 8 patients (31%). Delayed washout pattern in a nodule was correlated with the histologic diagnosis of thyroid carcinoma (P < .001). None of the nodules with thyroid carcinoma had a plateau or rapid washout pattern. The sensitivity and NPV of DCE-MRI to diagnose thyroid carcinoma were greater when compared with those in USG-guided FNAB (100 vs 71.4%, and 100 vs 91.7%, respectively; P < .001).

CONCLUSION

When other diagnostic methods are inconclusive, DCE-MRI is superior to USG-guided FNAB to exclude thyroid carcinoma in patients with multinodular goiter.

Thyroid FNAC cytology: can we do it better?

This article reviews recent developments in thyroid fine needle aspiration cytology (FNAC). While thyroid nodules are common, carcinoma is comparatively rare. Although histological assessment is used in most studies as the benchmark, the differential diagnosis on cytology or histology is not always reproducible. The literature shows wide variations in criteria for inadequate thyroid FNAC and study inclusion or exclusion criteria. In-clinic assessment of specimen adequacy and in-clinic reporting of thyroid FNAC has become popular although the costs and resource implications of in-clinic thyroid FNAC assessment and reporting are substantial. Many centres continue to use conventional techniques although liquid-based cytology and ultrasound-guided FNAC are gaining in popularity. Standardized categorical systems for FNAC reporting can make results easier to understand for clinicians and give clear indications for therapeutic action. Multidisciplinary case review is also essential, especially when there is diagnostic uncertainty. While currently of limited use, molecular pathology testing holds out some promise for the future.