Abstract
CONTEXT: Ethanol ablation (EA) is a treatment option in recurrent or persistent metastatic lymph nodes (MLNs) from papillary thyroid carcinoma. OBJECTIVE: This work aimed to assess whether ultrasonographic characteristics of the MLN, history of lymph node surgery, aggressive histological subtype, or BRAFV600E mutation in the primary tumor predict long-term response from EA. METHODS: Seventy-five patients who received EA at a tertiary referral center were included. We evaluated treatment response from the most recent clinically indicated examination, or a study-specific examination. BRAFV600E analysis and review of histological subtypes in the primary tumor were conducted. RESULTS: Median interval from initial surgery to follow-up was 119 months (range, 39-471 months). Pure cystic MLN had a better outcome than the solid and partially cystic MLN (13/13, 100% vs 90/121, 74%; P = .039). Small MLNs (≤0.5 mL) had a higher response rate compared to larger lesions (71/92, 77% vs 10/19, 53%; P = .045). We observed no difference in EA response between patients with or without the BRAFV600E mutation (80/99, 81% vs 17/25, 68%; P = .181) or an aggressive subtype (22/24, 92% vs 75/100, 75%; P = .099) in their primary tumors. EA achieved similar rates of locoregional disease control in neck regions with or without previous lymph node surgery (66% vs 63%, P = .825). CONCLUSION: EA was highly effective in pure cystic MLNs. Partially cystic or noncystic MLNs over 0.5 mL were less responsive, though many of these MLNs still showed a lasting response. BRAFV600E mutation, aggressive histological subtype, or absence of prior lymph node surgery did not negatively affect EA response.