Irreversible Electroporation for Recurrent or Metastatic Cervical Lymph Node Metastases From Thyroid Cancer: A Prospective Multicenter Single-Arm Study

This is a single-arm, open-label, multicenter, exploratory clinical trial designed to systematically evaluate the efficacy, safety, and patient benefit of ultrasound-guided irreversible electroporation (IRE) ablation for recurrent or metastatic cervical lymph node disease in patients with thyroid cancer after prior curative thyroid surgery and neck dissection. A total of 85 participants will be enrolled.

After providing written informed consent, participants will enter a screening period of up to 28 days. During screening, baseline imaging of target lymph nodes will be performed (contrast-enhanced ultrasound or computed tomography), and patient-reported and clinician-reported assessments will be completed, including quality of life, pain, neck appearance, and, when applicable, voice-related outcomes. Laboratory testing and immunology samples will also be collected.

Eligible participants will undergo the first IRE ablation on Day 0 under ultrasound guidance. Acute pain will be assessed using the Numeric Rating Scale (NRS) at 0, 4, 8, 24, 48, and 72 hours after the procedure, and all adverse events and device deficiencies will be recorded. The first imaging re-assessment will be performed at Day 30 (±7 days). If residual enhancement suggests incomplete ablation, one salvage IRE ablation may be performed within 14 days. After confirmation of no need for salvage ablation or after completion of salvage ablation, participants will enter follow-up.

Follow-up visits will occur every 3 months starting from Month 3 after the first (or salvage) ablation and will continue until 24 months or until imaging progression, withdrawal, death, or loss to follow-up, whichever occurs first. Imaging assessments will be performed at each follow-up visit. At 12 months, the volume reduction rate (VRR), complete disappearance rate, and recurrence rate of treated lymph nodes will be assessed. Patient-reported outcomes (ThyPRO-39, EQ-5D-5L, neck appearance satisfaction visual analog scale) and clinician-reported scar assessment (Vancouver Scar Scale) will be repeated at Months 1, 3, 6, and 12, with the Voice Handicap Index-10 collected as needed. Laboratory tests (blood count, biochemistry, electrolytes) and immunology samples will be collected every 3 months.

The primary efficacy endpoint is the lymph node volume reduction rate at 12 months after a single IRE ablation. Secondary efficacy endpoints include 12-month lymph node volume reduction rate after single and/or salvage ablation, complete disappearance rate and recurrence rate at 12 months, volume reduction rate at 12 months for lesions located in high-risk anatomical areas, progression-free survival and overall survival, and improvements in quality of life and cosmetic outcomes. Safety endpoints include the incidence of adverse events and serious adverse events graded by NCI CTCAE v5.0, device-related serious adverse events, acute pain tolerability (NRS area under the curve and the proportion of participants with NRS ≥4 of sustained duration), laboratory abnormalities, and changes in voice-related outcomes. Exploratory endpoints include longitudinal changes in immune cell subsets, immune checkpoint and inhibitory molecule expression, and serum cytokine/chemokine profiles. Adverse events will be followed from the last IRE procedure (including salvage ablation) through 12 months.