Ethanol Ablation of Metastatic Lymph Nodes in Patients With Papillary Thyroid Carcinoma-Predictors of Clinical Outcome.

Abstract

Ethanol ablation (EA) is a treatment option in recurrent or persistent metastatic lymph nodes (MLNs) from papillary thyroid carcinoma. 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. 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. 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). 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.