Early detection of suspicious lymph nodes in differentiated thyroid cancer

ABSTRACT

Background

Early identification of cervical lymph node (LN) metastases cervical lymph node metastases (CLNM) is crucial in the management of differentiated thyroid cancer differentiated thyroid cancer (DTC) as it influences the indication and the extent of surgery with an impact on the recurrence risk and overall survival. The present review focused on novel sensitive and specific diagnostic techniques, by searching through online databases like MEDLINE and Scopus up to February 2022.

Areas covered

The techniques identified included contrast-enhanced ultrasound (CEUS), dosage of fragment 21–1 of cytokeratin 19 (CYFRA 21–1) in lymph node fine needle aspiration washout, sentinel LN biopsy (SNB), and artificial intelligence (AI) – deep learning applied to ultrasonography and computed tomography. These methods displayed widely varying sensitivity and specificity results, ranging from approximately 60–100%. This variability is mainly due to the operator’s experience because of the great complexity of execution of these new techniques, which require a long-learning curve.

Expert opinion

Despite the appearance of many candidate methods to improve the detection of metastatic lymph nodes, none seem to be clearly superior to the tools currently used in clinical practice and FNA-Tg measurement remains the more accurate tool to detect neck recurrences and CLNM from DTC.

KEYWORDS:

• Thyroid cancer
• lymph node metastases
• thyroglobulin
• contrast-enhanced ultrasound
• sentinel lymph node biopsy
• fine needle aspiration washout
• CYFRA 21-1
• Artificial intelligence (AI) - deep learning

Article highlights

• Preoperative detection of LN metastases has an important impact on prognosis and recurrence in patients with DTC as it influences the indication and the extent of surgery with an impact on the recurrence risk and overall survival.

• New diagnostic techniques promising improvements in early detection of metastatic LNs in DTC include: CEUS (IVCEUS and LCEUS), dosage of fragment 21-1 of cytokeratin 19 (CYFRA 21-1) in LN FNA washout, SNB and AI – deep learning applied to US and CT.

• All these methods have great development potential, but none seem to be clearly superior to the tools currently used in clinical practice, especially because of a greater complexity of execution which requires a long learning curve and leads to widely varying sensitivity and specificity results based on the operator’s experience.

• To date, FNA-thyroglobulin (FNA-Tg) measurement remains the more accurate tool to detect neck recurrences and cervical metastases from DTC.

• Selective use of ultrasound (i.e. after excellent response only in case of rising Tg) and FNAC should be adopted to avoid over-diagnosis and overtreatment in DTC patients, taking into account that many small LN metastases are clinically insignificant.

Declaration of interest

L Giovanella is a member of the Roche Diagnostics advisory board and has received research grants and speaker honoraria from Roche Diagnostics and BRAHMS GmbH. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

The authors have no funding to report.