Diagnostic criteria of ultrasonographic examination for lateral node metastasis of papillary thyroid carcinoma

Diagnostic Accuracy of Ultrasound for the Evaluation of Lateral Compartment Lymph Nodes in Papillary Thyroid Carcinoma

AIMS

To evaluate the diagnostic accuracy of ultrasound (US) assessing the lateral compartment lymph node metastasis in patients with primary papillary thyroid carcinoma (PTC), and to demonstrate the incidence and patterns of the lateral lymph node metastasis.

METHODS

We retrospectively reviewed 198 patients with primary PTC who underwent thyroidectomy in addition to modified lateral neck dissections (MLND) involving level II to level V due to clinically positive lateral neck disease. A skilled and experienced single operator performed all US examinations. Surgical pathology results were accepted as the reference method and sensitivity, specificity, and diagnostic accuracy of US in detecting metastatic lymph nodes established using level-by-level analysis.

RESULTS

In the study cohort, 10.1% of the patients had lateral compartment lymph node metastases without any central compartment involvement. For the lateral compartment, 48.5% had level II, 74.7% had level III, 64.6% had level IV, and 29.3% of the patients had level V metastasis. None of the patients had isolated level V metastasis. The sensitivity, specificity, and diagnostic accuracy of US in identifying lateral lymph compartment metastasis ranged from 87% to 91.4%, 92% to 98.6% 92.4% to 96%, respectively. However, the sensitivity (74.7%) and diagnostic accuracy (76.2%) of US significantly decreased for the central compartment while specificity (90%) remained similar.

CONCLUSION

US performed by a skilled operator has an excellent diagnostic accuracy for the evaluation of lateral cervical lymph nodes in primary PTC; thus, might enable precise tailoring of the management strategies. Moreover, the high incidence of level V involvement favors MLND over selective approaches.

Meta-analysis of ultrasound for cervical lymph nodes in papillary thyroid cancer: Diagnosis of central and lateral compartment nodal metastases

PURPOSE

To evaluate the performance of preoperative ultrasound in the diagnosis of cervical lymph nodes metastases (CLNM) of papillary thyroid cancer (PTC) and its value in assisting cervical lymph node dissection (CLND).

METHODS

PubMed, EMBASE and Cochrane Library databases were searched to identify relevant studies up to Sep. 2017. Overall sensitivity, specificity, and diagnostic odds ratio (DOR) were used to assess the diagnostic efficacy of ultrasound in detecting central and lateral CLNM of PTC.

RESULTS

Nineteen studies comprising 4014 patients were included in the meta-analysis. The pooled sensitivity, specificity, DOR and area under curve (AUC) of ultrasound in detecting central CLNM were 0.33 (95% confidence interval (95% CI): 0.31-0.35), 0.93 (95% CI: 0.92-0.94), 5.63 (95% CI: 3.50-9.04), and 0.69, respectively; and lateral CLNM were 0.70 (95% CI: 0.68-0.72), 0.84 (95% CI: 0.82-0.85), 18.7 (95% CI: 10.3-33.9) and 0.88, respectively. We found that the rate of central CLNM of PTC was 48.0%, and 36.2% of the dissected lymph nodes were metastatic, meanwhile, the rate of lateral CLNM of PTC was 59.2%, and 46.6% of the dissected lymph nodes were metastatic in the meta-analysis.

CONCLUSIONS

Preoperative ultrasound demonstrates poor sensitivity in the diagnosis of central CLNM, and good diagnostic efficacy for lateral CLNM of PTC. Prophylactic central CLND is recommended to PTC patients due to the high incidence of central CLNM and low diagnostic efficacy of ultrasound.

Medullary Thyroid Carcinoma: Do Ultrasonography and F-DOPA-PET-CT Influence the Initial Surgical Strategy?

Background

At the time of diagnosis, one-third of medullary thyroid carcinoma (MTC) patients show lymph node (LN) or distant metastasis. A metastasized MTC requires different surgical strategies.

Objective

This study aimed to determine the value of ultrasound and [18F]fluoro-dihydroxyphenylalanine positron emission tomography with computed tomography (F-DOPA-PET-CT) in localizing MTC, as well as LN and distant metastasis.

Methods

The study included 50 patients (24 males/26 females) with preoperative ultrasound, F-DOPA-PET-CT, and histologically proven MTC. Imaging results were correlated with both preoperative basal calcitonin (bCt) levels and final histology.

Results

Tumors were classified as pT1a:17 (diameter, mean ± standard deviation: 5.8 ± 3.0 mm), pT1b:15 (15.0 ± 3.2 mm), pT2:9 (27.3 ± 7.0 mm), and pT3:9 (38.3 ± 24.2 mm). The median bCt level was 202 pg/mL (lower/upper quartile: 82/1074 pg/mL). Ultrasound was positive for tumor in 45/50 (92%) patients (20.0 ± 16.0 mm) and negative in 5 patients (3.2 ± 2.2 mm). Overall, 43/50 (86%) patients had positive F-DOPA local scans (20.0 ± 16.4 mm), while 7 (14%) patients were negative (7.7 ± 8.1 mm). Lastly, 21/50 (42%) patients had LN metastasis; 8/21 (38%) patients had positive LNs suspected with ultrasound, and 12/21 (57%) patients had positive LNs suspected with F-DOPA. Tumor and LN sensitivity of ultrasound was 92% and 43%, respectively, and 86% and 57% of F-DOPA-PET-CT, respectively. In 3/50 (6%) patients and 3/50 (6%) patients, mediastinal LN metastasis and distant metastasis, respectively, were diagnosed only by F-DOPA-PET-CT.

Conclusion

Ultrasound and F-DOPA-PET-CT are sensitive for the localization of MTC but not for the presence and location of LN metastasis (limitations: size/number). Only F-DOPA ensures the diagnosis of distant metastasis and influences the extent of LN surgery. Surgical strategy cannot be predicted based on neither ultrasound nor F-DOPA-PET-CT.

Active Surveillance for Papillary Thyroid Microcarcinoma: Challenges and Prospects

Active surveillance (AS) can be considered as an alternative to immediate surgery in low-risk papillary thyroid microcarcinoma (PTMC) without clinically apparent lymph nodes, gross extrathyroidal extension (ETE), and/or distant metastasis according to American Thyroid Association. However, in the past AS has been controversial, as evidence supporting AS in the management of PTMC was scarce. The most prominent of these controversies included, the limited accuracy and utility of ultrasound (US) in the detection of ETE, malignant lymph node involvement or the advent of novel lymph node malignancy during AS, and disease progression. We summarized publications and indicated: (1) US, performer-dependent, could not accurately diagnose gross ETE or malignant lymph node involvement in PTMC. However, the combination of computed tomography and US provided more accurate diagnostic performance, especially in terms of selection sensitivity. (2) Compared to immediate surgery patients, low-risk PTMC patients had a slightly higher rate of lymph node metastases (LNM), although the overall rate for both groups remained low. (3) Recent advances in the sensitivity and specificity of imaging and incorporation of diagnostic biomarkers have significantly improved confidence in the ability to differentiate indolent vs. aggressive PTMCs. Our paper reviewed current imagings and biomarkers with initial promise to help select AS candidates more safely and effectively. These challenges and prospects are important areas for future research to promote AS in PTMC.

Level V Clearance in Neck Dissection for Papillary Thyroid Carcinoma: A Need for Homogeneous Studies

Introduction  Papillary thyroid carcinoma has a very high rate of lateral neck node metastases, and there is almost unanimity concerning the fact that some sort of formal neck dissection must be performed to address the clinical neck disease in these cases. Although there is an agreement that levels II to IV need to be cleared in these patients, the clearance of level V is debatable.

Objectives  We herein have tried to analyze various papers that have documented a structured approach to neck dissection in these patients. Moreover, we have also tried to consider this issue through various aspects, like spinal accessory nerve injury and the impact of neck recurrence on survival.

Data Synthesis  The PubMed, Medline, Google Scholar, Surveillance, Epidemiology, and End Results (SEER), and Ovid databases were searched for studies written in English that focused on lateral neck dissection (levels II–IV or II–V) for papillary thyroid carcinoma. Case reports with 10 patients or less were excluded.

Conclusions  The current evidence is equivocal whether to clear level V or not, and the studies published on this issue are very heterogeneous. Level II-IV versus level II-V selective neck dissections in node-positive papillary thyroid carcinoma patients is far from categorical, with pros and cons for both approaches. Hence, we feel that there is a need for more robust homogeneous data in order to provide an answer to this question.

Pattern of spread to the lateral neck in metastatic well-differentiated thyroid cancer: a systematic review and meta-analysis

BACKGROUND

There remains controversy surrounding the extent of lateral neck dissection required in patients with papillary thyroid cancer (PTC) and suspicious or confirmed metastatic lateral neck lymphadenopathy. The evidence for this clinical dilemma has never been reviewed systematically nor has there been an attempt to meta-analyze the data by lymph node levels to better characterize the pattern of spread.

METHODS

This meta-analysis used MEDLINE and EMBASE including all cohort studies reporting the pattern of lateral neck disease in patients who underwent a neck dissection for clinically, radiographically, or cytologically suspicious or confirmed metastatic lymphadenopathy for PTC. Our main outcome was the number of patients with positive involvement at a given level as a percentage of the cohort of patients with positive lateral neck disease, each level being measured separately.

RESULTS

Eighteen studies with a total of 1145 patients and 1298 neck dissections were included in our meta-analysis. Levels IIa and IIb had disease in 53.1% [95% confidence interval (CI) 46.6-59.5%] and 15.5% [CI 8.2-27.2%], respectively. Studies that did not distinguish between level IIa and IIb or in which both were collapsed into one category showed a total level II involvement of 53.4% [CI 49.7-57.1%]. Level III and level IV were involved in 70.5% [CI 67.0-73.9%] and 66.3% [CI 61.4-70.9%] of specimens. Studies that did not distinguish between level Va and Vb or in which both were collapsed into one category showed a total level V involvement of 25.3% [CI 20.0-31.5%]. Levels Va and Vb had positivity in 7.9% [CI 2.8-20.0%] and 21.5% [CI 7.7-47.6%], respectively, but had only three studies that could be meta-analyzed.

CONCLUSIONS

This systematic review of the literature and meta-analysis of the pattern of spread indicates significant rates of lymph node metastasis to all lateral neck levels in patients with PTC with regional involvement. This evidence leads us to recommend a comprehensive selective neck dissection of levels IIa, IIb, III, IV, and Vb in patients with lateral neck disease from PTC. The evidence for level Va is lacking, as most studies did not distinguish between levels Va and Vb, and the border between the two levels was inconsistent. Future studies will need to address these sublevels separately.

Terminology inaccuracies in the interpretation of imaging results in detection of cervical lymph node metastases in papillary thyroid cancer

Cervical lymph nodes (CLNs) are the most common site of metastases in papillary thyroid cancer (PTC). Ultrasound scan (US) is the most commonly used imaging modality in the evaluation of CLNs in PTC. Computerised tomography (CT) and (18)fluorodeoxyglucose positron emission tomography ((18)FDG PET-CT) are used less commonly. It is widely believed that the above imaging techniques should guide the surgical approach to the patient with PTC.

METHODS

We performed a systematic review of imaging studies from the literature assessing the usefulness for the detection of metastatic CLNs in PTC. We evaluated the author's interpretation of their numeric findings specifically with regard to 'sensitivity' and 'negative predictive value' (NPV) by comparing their use against standard definitions of these terms in probabilistic statistics.

RESULTS

A total of 16 studies used probabilistic terms to describe the value of US for the detection of LN metastases. Only 6 (37.5%) calculated sensitivity and NPV correctly. For CT, out of the eight studies, only 1 (12.5%) used correct terms to describe analytical results. One study looked at magnetic resonance imaging, while three assessed (18)FDG PET-CT, none of which provided correct calculations for sensitivity and NPV.

CONCLUSION

Imaging provides high specificity for the detection of cervical metastases of PTC. However, sensitivity and NPV are low. The majority of studies reporting on a high sensitivity have not used key terms according to standard definitions of probabilistic statistics. Against common opinion, there is no current evidence that failure to find LN metastases on ultrasound or cross-sectional imaging can be used to guide surgical decision making.

Lateral cervical lymph node metastases in papillary thyroid cancer: a systematic review of imaging-guided and prophylactic removal of the lateral compartment

BACKGROUND

Papillary thyroid cancer (PTC) is a common endocrine cancer and frequently presents with lymph node (LN) metastases. The frequency of LN metastases in the lateral compartment and their surgical removal are poorly defined. There are no prospective randomised controlled trials addressing an eventual outcome difference relating to the extent of the initial surgical approach. The aim of this study was to define the extent of lateral LN involvement and the role of imaging in identification of these metastatic LN.

DESIGN AND METHODS

A systematic review of studies of patients with PTC undergoing either prophylactic or therapeutic lymphadenectomy of the lateral cervical compartment. Studies involving imaging modalities in the detection of lateral cervical LNs in PTC were also analysed.

RESULTS

Systematic review on the frequency of lateral LN metastases and their detection using various imaging tools identified 19 studies containing data on 5587 patients undergoing prophylactic or imaging-guided removal of the lateral compartment. Imaging-guided surgery retrieved cancerous lateral LNs in 446/3178 or 14% of eligible patients, whilst prophylactic lateral neck dissection yielded histopathological proof of cancer in 1177/204 or 57·5% of patients. The frequency of lateral compartment metastases increased with T stage. The sensitivity of ultrasound and CT was poor as low as 27% when accurately calculated.

CONCLUSION

Metastatic cervical LNs were found in more than half of patients when prophylactic lateral LN dissection was performed. Use of conventional imaging for the selection of the surgical approach to the lateral cervical compartment may commonly identify stage N1a instead of N1b and thus lead to false stage assignment as stage III rather than stage IV, concealing the severe prognostic implications of this stage progression in individual patients.

Late nodal metastasis of T2 oral cancer can be reduced by a combination of preoperative ultrasonographic examination and frozen section biopsy during supraomohyoid neck dissection

CONCLUSION

The occult metastasis rate for T2 oral cancer can be reduced by ultrasonography (US). Also, the late metastasis rate is considered to be reduced by combining US with frozen section biopsy (FSB) during supraomohyoid neck dissection (SOHND).

OBJECTIVES

Early oral cancer has been reported to show occult metastases in 15-53% of patients, but the criteria or methods for the diagnosis of cervical lymph node metastasis are unclear in many studies, and there is no clear definition of occult metastasis. In patients with T2 oral cancer, the diagnosis of lymph node metastasis by US and its pathological diagnosis (pN) after neck dissection were compared to evaluate the usefulness and limitations of US, occult metastasis rate, significance of SOHND as preventive neck dissection, and use of FSB.

METHODS

A total of 73 patients with T2 oral cancer were investigated retrospectively. Modified radical neck dissection (MRND) was performed in N+ patients, and SOHND was carried out in N0 patients. FSB was performed in all patients undergoing SOHND. US and pN diagnoses were compared.

RESULTS

The occult metastasis rate was 18% when occult metastases were limited to those detected by SOHND and 22% when late nodal recurrences were also included.