Optimized cutoff value and indication for washout thyroglobulin level according to ultrasound findings in patients with well-differentiated thyroid cancer

Application of deep-learning to the automatic segmentation and classification of lateral lymph nodes on ultrasound images of papillary thyroid carcinoma

PURPOSE

It is crucial to preoperatively diagnose lateral cervical lymph node (LN) metastases (LNMs) in papillary thyroid carcinoma (PTC) patients. This study aims to develop deep-learning models for the automatic segmentation and classification of LNM on original ultrasound images.

METHODS

This study included 1000 lateral cervical LN ultrasound images (consisting of 512 benign and 558 metastatic LNs) collected from 728 patients at the Chongqing General Hospital between March 2022 and July 2023. Three instance segmentation models (MaskRCNN, SOLO and Mask2Former) were constructed to segment and classify ultrasound images of lateral cervical LNs by recognizing each object individually and in a pixel-by-pixel manner. The segmentation and classification results of the three models were compared with an experienced sonographer in the test set.

RESULTS

Upon completion of a 200-epoch learning cycle, the loss among the three unique models became negligible. To evaluate the performance of the deep-learning models, the intersection over union threshold was set at 0.75. The mean average precision scores for MaskRCNN, SOLO and Mask2Former were 88.8%, 86.7% and 89.5%, respectively. The segmentation accuracies of the MaskRCNN, SOLO, Mask2Former models and sonographer were 85.6%, 88.0%, 89.5% and 82.3%, respectively. The classification AUCs of the MaskRCNN, SOLO, Mask2Former models and sonographer were 0.886, 0.869, 0.90.2 and 0.852 in the test set, respectively.

CONCLUSIONS

The deep learning models could automatically segment and classify lateral cervical LNs with an AUC of 0.92. This approach may serve as a promising tool to assist sonographers in diagnosing lateral cervical LNMs among patients with PTC.

Thyroglobulin in lymph node fine-needle aspiration biopsy washout fluid. A tertiary center experience

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Most PTC secretes thyroglobulin, a useful marker in monitoring preoperative staging and postoperative progression; in addition to serum thyroglobulin, fine needle aspiration washout thyroglobulin (FNA-Tg) is also used. Our aim was to determine the cut-off value for FNA-Tg in our center and to describe major discrepancies between FNA-Tg, cytology and pathology results of the lymph nodes. Methods: We retrospectively retrieved from the electronic database of our endocrinology center all the FNA-Tg measurements between December 10, 2019 and September 2021. For each measurement we also retrieved the corresponding sex, FNAB results and the pathology reports. FNA-Tg was measured by ECLIA immunoelectro-chemiluminescent method. Results: There were 58 FNAB and FNA-Tg of suspect cervical lymph nodes in 40 patients. There were 17 cytologically benign lymph nodes of which 13 had low and 4 had high FNA-Tg; 3 non-diagnostic cytology results of which one had high FNA-Tg; 38 PTC metastases of which 6 had low and 32 had high FNA-Tg titers. The cut-off value of FNA-Tg in our center is 10 ng/ml, with a sensitivity of 86.6% (in those with pathology reports available after surgery). Conclusions: Washout TG is useful in suspicious lymph nodes and has added value to cytology in selected cases. The cut-off value of FNA-Tg in our center is 10 ng/ml, with a sensitivity of 86.6%. However, we must consider the possible false negative results that may occur in some histological types of PTC.

Computed tomography complements ultrasound for the differential diagnosis of traumatic neuroma from recurrent tumor in patients with postoperative thyroid cancer

OBJECTIVES

Traumatic neuromas (TNs) mimic recurrent tumors in US after total thyroidectomy (TT) and lateral neck dissection (LND) for thyroid cancer. We aimed to evaluate whether CT could complement US in the differential diagnosis of TNs from recurrent thyroid cancer in the dissected neck.

MATERIAL AND METHODS

We retrospectively included a total of 97 consecutive US-detected lesions (28 TNs and 69 recurrent tumors) in patients with a previous history of TT and LND for thyroid cancer. The lesions were classified as benign, indeterminate, or suspicious according to the presence of benign or suspicious features on US and CT. Imaging features and categories on US and CT were compared between TNs and recurrent tumors. The diagnostic performances of US and CT for differentiating between TNs and recurrent tumors were calculated.

RESULTS

On US, most TNs and recurrent tumors showed internal hyperechogenicity without hilar echogenicity or hilar vascularity and were categorized as suspicious lesions (23/28, 82.1% vs. 53/69, 76.8%). On CT, all TNs lacked strong enhancement without hilar fat or hilar vessel enhancement and were categorized as indeterminate lesions (28/28, 100%). In contrast, most recurrent tumors showed strong enhancement and were categorized as suspicious lesions (63/69, 91.3%). The addition of CT to US corrected 23 false-positive diagnoses in 28 TNs and 10 false-negative diagnoses in 69 recurrent tumors.

CONCLUSIONS

CT complements US for the correct differentiation of TNs from recurrent tumors in postoperative thyroid cancer patients. The addition of CT to US may prevent unnecessary painful biopsy or surgery.

KEY POINTS

• In the dissected neck, traumatic neuromas could mimic US suspicious LNs owing to its internal hyperechogenicity. • CT effectively differentiated traumatic neuromas from recurrent thyroid cancers by demonstrating significantly different enhancement patterns. • CT could complement US and may prevent unnecessary painful biopsy or surgery for US-detected lesions after thyroidectomy and neck dissection.

Diagnostic Algorithm for Metastatic Lymph Nodes of Differentiated Thyroid Carcinoma

Simple Summary

Fine-needle aspiration cytology (FNAC) with measurement of thyroglobulin concentrations obtained through aspiration (FNA-Tg) is routinely used for the diagnosis of metastatic lymph nodes (LNs) from differentiated thyroid carcinomas. However, some areas of uncertainty remain, including the optimal FNA-Tg cutoff and its interpretation based on ultrasound (US) features. In this study, we evaluated the appropriate strategies for interpreting FNAC and FNA-Tg results based on the sonographic features of LNs. We confirmed that the malignancy rate of LNs found to be malignant by FNAC or elevated FNA-Tg was sufficiently high to be diagnosed as metastasis, regardless of the sonographic features. The malignancy rate of LNs with indeterminate or benign FNAC findings and low FNA-Tg were stratified according to their sonographic features. We propose a diagnostic algorithm, based on combined FNAC, FNA-Tg, and US features of LNs, for diagnosing metastatic LNs of differentiated thyroid carcinomas.

Abstract

We aimed to evaluate appropriate strategies for interpreting fine-needle aspiration cytology (FNAC) and thyroglobulin concentrations obtained through aspiration (FNA-Tg) results based on the sonographic features of lymph nodes (LNs). Consecutive patients who underwent ultrasound-guided FNAC and FNA-Tg for metastatic LNs from differentiated thyroid carcinomas (DTCs) from January 2014 to December 2018 were reviewed retrospectively. LNs were categorized sonographically as suspicious, indeterminate, or benign. The optimal FNA-Tg cutoff for metastatic LNs was evaluated preoperatively, after lobectomy, and after total thyroidectomy. The diagnostic performances of FNA-Tg, FNAC, and their combination were analyzed based on the sonographic features of LNs. The malignancy rates of LNs were analyzed based on the sonographic features, FNAC, and FNA-Tg results. Of the 1543 LNs analyzed, 528 were benign, whereas 1015 were malignant. FNA-Tg increased the sensitivity and accuracy of FNAC for LNs. The malignancy rate of LNs found to be malignant by FNAC or elevated FNA-Tg ranged from 82% to 100%, regardless of the sonographic features. The malignancy rate of LNs with indeterminate or benign FNAC findings and low FNA-Tg were stratified according to their sonographic features. We propose a diagnostic algorithm, based on combined FNAC, FNA-Tg, and ultrasound features of LNs, for diagnosing metastatic LNs of DTCs.

Comparison of the diagnostic performances of US-guided fine needle aspiration cytology and thyroglobulin measurement for lymph node metastases in patients with differentiated thyroid carcinoma: a meta-analysis

OBJECTIVES

Ultrasound (US)-guided fine needle aspiration cytology (FNAC) and thyroglobulin measurement (FNA-Tg) are two common methods for confirming lymph node metastases (LNM) in patients with differentiated thyroid carcinoma (DTC). This study aimed at comparing the diagnostic performance of FNAC, FNA-Tg alone, and in combination by means of a meta-analysis.

METHODS

Eligible articles were selected according to predefined criteria, and their quality was evaluated as per the QUADAS-2 checklist. We calculated pooled sensitivity (Se), specificity (Sp), positive/negative likelihood ratio, and diagnostic odds ratio (DOR), and plotted the summary receiver operating characteristic (SROC) curve using the Meta-DiSc1.4 software.

RESULTS

Twenty-one studies pooling 1662 malignant and 1279 benign LNs from 2712 patients with DTC were included. The results showed that FNAC was more specific (pooled Sp, 0.98) while FNA-Tg was more sensitive (pooled Se, 0.94). FNAC and FNAC+FNA-Tg performed better postoperatively than FNA-Tg, while FNA-Tg performed better preoperatively. The combination of FNAC and FNA-Tg could achieve a better diagnostic performance than each alone (DOR 446.00, area under the curve [AUC] 0.9862), no matter preoperatively (DOR 378.14, AUC 0.9879) or postoperatively (DOR 788.72, AUC 0.9930). Besides, the combination of FNAC and FNA-Tg/serum-Tg ratio obtained a higher Sp (0.98) than the combination of FNAC and FNA-Tg.

CONCLUSION

The addition of FNA-Tg, especially the FNA-Tg/serum-Tg ratio, to FNAC could increase the diagnostic performance of LNM in both preoperative and postoperative patients with DTC. Since one test or test combinations could perform differently according to the clinical situation, the best-fitting test should be chosen accordingly.

KEY POINTS

• FNAC is more specific than FNA-Tg while FNA-Tg is more sensitive than FNAC. • The combination of FNAC and FNA-Tg could achieve a better diagnostic performance than either alone, no matter preoperatively or postoperatively. • The combination of FNAC and FNA-Tg/serum-Tg ratio could reach a higher Sp than the combination of FNAC and FNA-Tg.

Diagnostic values of thyroglobulin in lymph node fine-needle aspiration washout: a systematic review and meta-analysis diagnostic values of FNA-Tg

Thyroglobulin measurement in the needle washout after fine-needle aspiration (FNA-Tg) served as an important measurement for suspicious recurrent or metastatic lesions. We conducted a pooled analysis to evaluate the diagnostic accuracy of FNA-Tg and searched electronic databases for original articles in English from 1993 through 2017. Finally, a total of 22 studies containing 2,670 lymph nodes (LNs) that enrolled participants with suspicious neck LNs during thyroid nodule workup or papillary thyroid cancer (PTC) follow-up were included. In our analysis, the overall pooled sensitivity for FNA-Tg was 0.91 (95%CI: 0.87-0.93), specificity was 0.94 (95% CI: 0.91-0.96). Meta regression revealed that the cutoff value and status of serum Tg were sources of heterogeneity for sensitivity, and the cutoff value was source of heterogeneity for specificity. Additionally, the cutoff value and status of serum Tg were sources of heterogeneity in the joint model. Subgroup analysis about cut-off value showed that the choice of 1 ng/mL had highest sensitivity, 40 ng/mL had highest specificity. At last, we arrived at the conclusion that FNA-Tg measurement had high specificity and sensitivity in the early detection of LNs metastases from PTC by our meta-analysis. The technique was simple and could be recommended to apply in any FNA facility, especially when LN were small-sized. Significantly, a better standardization of criteria for FNA-Tg detection and cutoff value was required to provide useful data and to improve management of PTC patients in the future.

BRAFv600e mutation combined with thyroglobulin and fine-needle aspiration in diagnosis of lymph node metastasis of papillary thyroid carcinoma

BACKGROUND

Papillary thyroid carcinoma (PTC) is often associated with cervical lymph node metastasis (LNM), which may cause poor prognosis. Both fine-needle aspiration cytology (FNAC) and thyroglobulin measurement with fine-needle aspiration (Tg-FNA) have high diagnostic efficacy, but the diagnostic values and relationships among BRAF_v600e mutation (BRAF^MUT) testing, FNAC and FNA-Tg are unclear.

METHODS

We enrolled 145 patients with confirmed PTC and lymph nodes (LNs) that were suspected to be metastatic based on ultrasound findings, who were treated from May 2017 to April 2018, and underwent FNAC, Tg-FNA and BRAF^MUT tests. Diagnostic efficacy was calculated by diagnostic and chi-square tests.

RESULTS

Diagnostic values were FNAC-sensitivity: 67%, specificity: 100%, PPV: 100%, NPV: 66%, accuracy: 80%; and FNA-Tg (at a cut-off of 2.23 ng/mL)-sensitivity: 97.3%, specificity: 87.8%, PPV: 87.8%, NPV: 97.3%, accuracy: 92.3%. In the BRAF^MUT+ group, sensitivities and specificities were FNAC: 68.6% and 100%, Tg-FNA: 94.4% and 85.7%; compared with FNAC: 75% and 90.9%, Tg-FNA: 80% and 100% in the BRAF^MUT- group.

CONCLUSION

The combination of Tg-FNA + FNAC is useful in diagnosing metastatic PTC. BRAF mutational status does not affect the diagnostic performance of FNAC or Tg-FNA.

Lymph node fine-needle aspiration washout thyroglobulin in papillary thyroid cancer: Diagnostic value and the effect of thyroglobulin antibodies

PURPOSE

Thyroglobulin (Tg) assessment in the needle washout after fine-needle aspiration biopsy (FNAB) of a suspicious neck lymph node (LN) is known to improve the diagnostic accuracy in patients with papillary thyroid cancer (PTC). However, there is still controversy on the best diagnostic cut-off levels for FNAB-Tg and whether thyroglobulin antibody (TgAb) positivity affects FNAB-Tg. The objectives of this study were to determine (i) the diagnostic power of different cut-offs for FNAB-Tg and (ii) if serum TgAb(+) negatively affects the FNAB-Tg evaluation.

METHODS

This was a retrospective cohort study analyzing PTC patients with suspicious neck LNs, in a university hospital setting, from October 2009 to October 2013. In total, 103 patients with PTC (226 LNs) undergoing ultrasound-guided FNAB for LNs were included. Cytology and FNAB-Tg levels were compared in reference to LN histopathology and the effect of TgAb(+) on FNAB-Tg levels was evaluated.

RESULTS

The diagnostic accuracies of FNAB-Tg cut-off of 1 and 10 ng/mL were 94.1% and 88.2%, respectively. Raising the cut-off from 1 to 10 ng/mL led to decreased sensitivity rates (91.9% vs. 83.9%). The receiver operating characteristic curve analysis demonstrated that the best FNAB-Tg cut-off was 1.2 ng/mL. There were no LNs with an FNAB-Tg ≥ 10 ng/mL that turned out to be cytologically or histopathologically benign. FNAB-Tg levels of the histopathologically malignant LNs were similar between TgAb (+) and TgAb (-) patients (p = 0.546). Serum Tg predicted FNAB-Tg levels above 1 ng/mL (p = 0.002) and FNAB-Tg predicted malignant histopathology (p = 0.004), both independently of the TgAb status of the patient.

CONCLUSIONS

FNAB-Tg ≥ 1 ng/mL has a superior diagnostic power, irrespective of TgAb (+), in PTC patients with suspected LN involvement.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS, AMERICAN COLLEGE OF ENDOCRINOLOGY, AND ASSOCIAZIONE MEDICI ENDOCRINOLOGI MEDICAL GUIDELINES FOR CLINICAL PRACTICE FOR THE DIAGNOSIS AND MANAGEMENT OF THYROID NODULES--2016 UPDATE

Thyroid nodules are detected in up to 50 to 60% of healthy subjects. Most nodules do not cause clinically significant symptoms, and as a result, the main challenge in their management is to rule out malignancy, with ultrasonography (US) and fine-needle aspiration (FNA) biopsy serving as diagnostic cornerstones. The key issues discussed in these guidelines are as follows: (1) US-based categorization of the malignancy risk and indications for US-guided FNA (henceforth, FNA), (2) cytologic classification of FNA samples, (3) the roles of immunocytochemistry and molecular testing applied to thyroid FNA, (4) therapeutic options, and (5) follow-up strategy. Thyroid nodule management during pregnancy and in children are also addressed. On the basis of US features, thyroid nodules may be categorized into 3 groups: low-, intermediate-and high-malignancy risk. FNA should be considered for nodules ≤10 mm diameter only when suspicious US signs are present, while nodules ≤5 mm should be monitored rather than biopsied. A classification scheme of 5 categories (nondiagnostic, benign, indeterminate, suspicious for malignancy, or malignant) is recommended for the cytologic report. Indeterminate lesions are further subdivided into 2 subclasses to more accurately stratify the risk of malignancy. At present, no single cytochemical or genetic marker can definitely rule out malignancy in indeterminate nodules. Nevertheless, these tools should be considered together with clinical data, US signs, elastographic pattern, or results of other imaging techniques to improve the management of these lesions. Most thyroid nodules do not require any treatment, and levothyroxine (LT4) suppressive therapy is not recommended. Percutaneous ethanol injection (PEI) should be the first-line treatment option for relapsing, benign cystic lesions, while US-guided thermal ablation treatments may be considered for solid or mixed symptomatic benign thyroid nodules. Surgery remains the treatment of choice for malignant or suspicious nodules. The present document updates previous guidelines released in 2006 and 2010 by the American Association of Clinical Endocrinologists (AACE), American College of Endocrinology (ACE) and Associazione Medici Endocrinologi (AME).

Influence of thyroid gland status on the thyroglobulin cutoff level in washout fluid from cervical lymph nodes of patients with recurrent/metastatic papillary thyroid cancer

BACKGROUND

The influence of serum thyroglobulin (Tg) and thyroidectomy status on Tg in fine-needle aspiration cytology (FNAC) washout fluid is unclear.

METHODS

A total of 282 lymph nodes were prospectively subjected to FNAC, fine-needle aspiration (FNA)-Tg measurement, and frozen and permanent biopsies. We evaluated the diagnostic performance of several predetermined FNA-Tg cutoff values for recurrence/metastasis in lymph nodes according to thyroidectomy status.

RESULTS

The diagnostic performance of FNA-Tg varied according to thyroidectomy status. The optimized cutoff value of FNA-Tg was 2.2 ng/mL. However, among FNAC-negative lymph nodes, the FNA-Tg cutoff value of 0.9 ng/mL showed better diagnostic performance in patients with a thyroid gland. An FNA-Tg/serum-Tg cutoff ratio of 1 showed the best diagnostic performance in patients without a thyroid gland.

CONCLUSION

Applying the optimal cutoff values of FNA-Tg according to thyroid gland status and serum Tg level facilitates the diagnostic evaluation of neck lymph node recurrences/metastases in patients with papillary thyroid carcinoma (PTC). © 2015 Wiley Periodicals, Inc. Head Neck 38: E1705-E1712, 2016.

Lowered cutoff of lymph node fine-needle aspiration thyroglobulin in thyroid cancer patients with serum anti-thyroglobulin antibody

OBJECTIVE

Fine needle aspiration cytology (FNAC) and measurement of thyroglobulin (Tg) in needle washout (FNA-Tg) are recommended for the diagnosis of metastatic or recurrent lymph nodes (LNs) in differentiated thyroid cancer (DTC). However, the effect of serum Tg antibody (TgAb) on FNA-Tg levels still remains unclear in the preoperative setting. We analyze the interference of serum TgAb on FNA-Tg levels as proof of concept in the diagnostic advantage of serum TgAb combined with FNA-Tg.

SUBJECTS AND METHODS

A total of 370 suspicious cervical LNs from 273 patients with DTC were included. The primary tumor was confirmed as DTC on preoperative pathology in all patients. We performed FNA-Tg measurement and FNAC on suspicious LNs and evaluated the diagnostic performance of FNAC and FNA-Tg according to TgAb status. Final diagnoses were confirmed by histological examination of excised specimens or by follow-up ultrasonography for at least 6 months.

RESULTS

Data from 273 subjects with suspicious 370 LNs were evaluated. Fifty-five LNs (14.9%) were from TgAb+ positive serum TgAb (TgAb+) patients. Serum Tg and FNA-Tg levels were significantly lower in patients with TgAb+ than in those with TgAb-negative (TgAb-). Final pathology confirmed 109 LNs (29.5%) as malignant. Diagnostic performance of FNA-Tg at the same cutoff level was lower in the TgAb+ than TgAb- group. FNA-Tg cutoff levels determined by ROC curve were lower in the TgAb+ group.

CONCLUSION

The results suggested that the cutoff value of FNA-Tg should be lowered in suspicious LN before thyroidectomy in thyroid cancer patients with TgAb.

A Study on Serum Antithyroglobulin Antibodies Interference in Thyroglobulin Measurement in Fine-Needle Aspiration for Diagnosing Lymph Node Metastasis in Postoperative Patients

Purpose

Thyroglobulin measurement in fine-needle aspiration washout fluid (FNA-Tg) is widely used for detection of lymph node metastasis (LNM) in patients with papillary thyroid cancer (PTC). Recent studies suggested that serum anti-thyroglobulin antibodies (TgAbs) could interfere with FNA-Tg. We evaluated whether TgAbs can affect FNA-Tg when diagnosing LNM in postoperative patients with PTC.

Methods

From November 2006 to June 2011, a total of 239 LNs from 201 patients who underwent bilateral thyroidectomy and radioactive iodine ablation therapy were included. The interactions between FNA-Tgs and serum TgAbs, and diagnostic performances between FNA with additional FNA-Tg and FNA alone according to the presence of serum TgAbs were evaluated using the generalized linear mixed model and the bootstrap method.

Results

From 106 (44.4%) malignant and 133 (55.6%) benign LNs, there were 32 (13.4%) LNs with detectable serum TgAb levels and 207 (86.6%) LNs with undetectable serum TgAb levels. In logistic regression analysis, a significant negative interaction was observed between FNA-Tgs and serum TgAbs (p = 0.031). In the absence of serum TgAbs, the diagnostic performances were superior in the FNA with FNA-Tg than in the FNA only. However, in the presence of serum TgAbs, the diagnostic performances of the FNA with FNA-Tg were not significantly different from the FNA only, even with a different cutoff value of FNA-Tg.

Conclusions

Serum TgAbs may interfere with FNA-Tg studies and caution is advised while analyzing FNA-Tg for detection of LNM in patients with PTC.

Thyroglobulin level in fine-needle aspirates for preoperative diagnosis of cervical lymph node metastasis in patients with papillary thyroid carcinoma: two different cutoff values according to serum thyroglobulin level

BACKGROUND

Measurement of thyroglobulin (Tg) in the washout fluid of fine-needle aspirates (FNA-Tg) is useful for diagnosis of lymph node (LN) metastasis in papillary thyroid carcinoma (PTC). However, the cutoff value of FNA-Tg in the preoperative state is not defined clearly. This study aimed to evaluate the optimal cutoff value of preoperative FNA-Tg according to serum Tg level.

METHODS

FNA-Tg was measured in 135 PTC patients (160 LNs) for preoperative diagnosis of cervical LN metastasis.

RESULTS

Of the 160 LNs, 119 (74%) were surgically removed and 110 (69%) were diagnosed as malignant. When we adopted a FNA-Tg of 1.0 μg/L as the cutoff value, the sensitivity and specificity were 99% and 76%, respectively. FNA-Tg levels were correlated with serum Tg levels (Pearson's coefficient 0.42, p=0.002) and the FNA-Tg levels of 12 of the 50 benign LNs were above 1.0 μg/L. We classified the LNs into two groups according to serum Tg level regardless of anti-Tg antibody status: a low Tg group (≤1.0 μg/L, n=22, 14%) and a high Tg group (>1.0 μg/L, n=138, 86%). In the low Tg group, the sensitivity and specificity of the FNA-Tg cutoff value of 1.0 μg/L were 93% and 100%, respectively. In the high Tg group, the sensitivity and specificity of the FNA-Tg cutoff value of 19.0 μg/L were 93% and 100%, respectively. A Tg ratio (FNA-Tg level divided by serum Tg level) of 0.5 gave an improved diagnostic performance (sensitivity, 98%; specificity, 98%) in the high Tg group.

CONCLUSIONS

FNA-Tg levels in the preoperative state are affected by serum Tg levels when they exceeded 1.0 μg/L. For the preoperative diagnosis of metastatic cervical LNs, it seems reasonable to employ different cutoff values of FNA-Tg depending on serum Tg levels. We propose the use of an optimal cutoff value of FNA-Tg of 1.0 μg/L in patients with low serum Tg levels and a Tg ratio of 0.5 in those with high serum Tg levels irrespective of thyroglobulin antibody status.

Thyroglobulin in lymph node fine-needle aspiration washout: a systematic review and meta-analysis of diagnostic accuracy

CONTEXT

The thyroglobulin measurement in the needle washout after fine-needle aspiration (FNA) has been reported to increase the sensitivity of FNA in identifying lymph node (LN) metastases from differentiated thyroid cancer (DTC).

OBJECTIVE

The aim of the study was to estimate the diagnostic accuracy of this technique.

DATA SOURCES

To identify eligible studies, we searched electronic databases for original articles in English from 1975 through 2013.

STUDY SELECTION

Studies that enrolled participants with suspicious neck LNs during thyroid nodule workup or thyroid cancer follow-up were included.

DATA EXTRACTION

Working independently, authors used a standard form to extract data. For quality assessment, QUADAS2 guidelines were applied.

DATA SYNTHESIS

Including all the selected studies (24 studies, 2865 LNs) in the pooled analysis, overall sensitivity was 95.0% (95% confidence interval [CI], 93.7-96.0%), specificity was 94.5% (95% CI, 93.2-95.7%), and diagnostic odds ratio (DOR) was 338.91 (95% CI, 164.82-696.88) with significant heterogeneity (inconsistency [I(2)] = 65.7%; heterogeneity, P < .001). Stratifying different populations and including only patients with thyroid gland (410 LNs), pooled sensitivity was 86.2% (95% CI, 80.9-90.5%), specificity was 90.2% (85.1-94.0%), and DOR was 56.621 (22.535-142.26; I(2) = 37.3%; heterogeneity, P = .121). Including only patients after thyroidectomy (1007 LNs), pooled sensitivity was 96.9% (95% CI, 94.9-98.2%), specificity was 94.1% (91.7-96.0%), and DOR was 407.65 (198.67-836.46; I(2) = 0.0%; heterogeneity, P = .673).

CONCLUSIONS

Thyroglobulin measurement in washout from LN FNA has high accuracy in early detection of nodal metastases from DTC. The technique is simple, but a better standardization of criteria for patient selection, analytical methods, and cutoff levels is required.

Measurement of fine-needle aspiration thyroglobulin levels increases the detection of metastatic papillary thyroid carcinoma in cystic neck lesions

BACKGROUND

Patients with previously resected papillary thyroid carcinoma (PTC) are monitored for disease recurrence/metastasis by ultrasound surveillance and fine-needle aspiration (FNA) cytology. However, accurate diagnosis in lesions with cystic degeneration may be difficult due to scant cellularity. In the current study, the authors evaluated thyroglobulin in FNA (Tg-FNA) for detecting metastatic and/or recurrent PTC in patients with cystic neck lesions after thyroidectomy.

METHODS

The pathology records were retrospectively searched for patients with previously resected PTC and subsequent Tg-FNA on a cystic neck mass. Tg-FNA was measured in needle rinses using a Tg assay. The ultrasound findings, Tg-FNA concentrations, and cytological and follow-up histological diagnoses were correlated.

RESULTS

A total of 21 FNA specimens of cystic lesions from 19 patients were identified. Of 7 cases with cytologic and subsequent histologic diagnoses of metastatic PTC, the median Tg-FNA level was 100,982 ng/mL. Of 8 cytologically benign cases, 7 cases had Tg-FNA levels < 0.2 ng/mL, and 1 aberrant case demonstrated elevated Tg-FNA of > 1000 ng/mL. For 6 cytologically equivocal cases, including 3 classified as atypical/suspicious for carcinoma, 2 classified as insufficient/acellular debris, and 1 classified as spindle cell neoplasm, 4 patients demonstrated markedly elevated Tg-FNA levels (> 150 ng/mL) with subsequent surgical confirmation of metastatic PTC, whereas 2 patients had Tg-FNA levels of < 0.2 ng/mL with negative follow-up. Using a cutoff value of 0.2 ng/mL, Tg-FNA demonstrated a sensitivity of 100% and specificity of 87.5%.

CONCLUSIONS

Tg-FNA is a useful ancillary test that improves the detection of cystic PTC metastases. Particularly in cytologically nondiagnostic cases, the measurement of Tg-FNA helps to distinguish benign from malignant cystic lesions.