Lymph node imaging for thyroid cancer

Area of Science:

• Oncology
• Radiology
• Head and Neck Surgery

Background:

• Cervical lymph node (LN) metastases are frequent in thyroid cancer, primarily in central (level VI) and lateral (levels II-V) neck compartments.
• Prophylactic lymph node dissections are rarely performed due to morbidity concerns and lack of survival benefit, emphasizing the need for selective approaches.

Purpose of the Study:

• To review current preoperative and postoperative imaging and diagnostic strategies for cervical lymph node metastases in thyroid cancer.
• To highlight the role of imaging and fine-needle aspiration in guiding selective lymph node dissections and surveillance.

Main Methods:

• Preoperative assessment using cervical ultrasound (US) and contrast-enhanced computed tomography (CT) to characterize LNs based on size, morphology, and growth.
• US-guided fine-needle aspiration (FNA) with thyroglobulin (Tg) washout for equivocal LNs.
• Postoperative surveillance utilizing US, CT, Tg levels, and occasionally thyroid uptake scans or positron emission tomography (PET).

Main Results:

• US and CT effectively characterize LNs in levels II-VI, assessing malignancy risk.
• US-guided FNA with Tg washout provides definitive diagnosis for suspicious LNs.
• Postoperative surveillance with imaging and biochemical markers aids in detecting recurrence.

Conclusions:

• Selective lymph node dissection is crucial in managing thyroid cancer cervical metastases.
• A multimodal approach combining imaging (US, CT), FNA, and biochemical markers is essential for accurate diagnosis and effective surveillance.