Clinical Effects of Microwave Ablation in the Treatment of Low-Risk Papillary Thyroid Microcarcinomas and Related Histopathological Changes.

Chenya Lu,Ruiping Li,Xiaoqiu Chu,Chao Liu,Jie Li,Yang Xu,Yalin Wang,Shuhang Xu,Xingjia Li,Guofang Chen,Jianhua Wang

doi:10.3389/fendo.2021.751213

Abstract

ObjectiveThis study aimed to evaluate the feasibility and efficacy of ultrasound-guided percutaneous microwave ablation (MWA) in the treatment of low-risk papillary thyroid microcarcinoma (PTMC), and to observe the histopathological changes after MWA.MethodsMWA was performed under ultrasound guidance for 73 unifocal PTMC patients without clinically cervical or distant metastasis. The target ablation zone exceeded the tumor edge (judged by contrast-enhanced US) to avoid marginal residue and recurrence. Ultrasound evaluation was performed at 1 day, 1, 3, 6, 12 and 24 months after treatment, and thyroid function evaluation at the first 6 months. Repeated fine needle aspiration cytology or core needle biopsy pathology was performed at 3 or 6 months after MWA to evaluate residual tumors. Any adverse event associated with MWA was evaluated.ResultsThe follow-up after MWA lasted 6 (6, 12) months. Tumor volume decreased significantly from 0.06 mm3 (0.04, 0.11 mm3) to 0.03 mm3 (0.00, 0.06 mm3) at 12 months after MWA (P< 0.001), with a median volume reduction ratio of 80.28% (-7.43, 100%) and 16 cases (21.92%) presenting complete remission. The largest diameter, volume and ablation energy were found to be different in patients with and without complete remission 12 months after MWA. On histopathological examinations, no atypical or malignant follicular cells were identified after thermal ablation. The most common pathological characteristics were fibroblastic proliferation (34/39, 87.18%) and chronic inflammation (32/39, 82.05%), followed by infarction (21/39, 53.85%). Five patients were transferred to thyroidectomy and 4 of them were confirmed with local recurrence and/or lymph node metastasis. Serum thyrotropin decreased transiently after MWA (P< 0.01) but normalized thereafter. No serious and permanent complications were reported.ConclusionsMWA is a safe and effective treatment for low-risk PTMC. Fibroblastic proliferation and chronic inflammation are the most common pathological changes after MWA of PTMC.

Highlights

Thyroid carcinoma has seen an incidence rising the fastest recently
Its application is doubted by potential tumor residues and lymphatic metastasis, microwave ablation (MWA) still exhibits higher safety and less trauma in its limited treatment of low-risk papillary thyroid microcarcinoma (PTMC) cases in China
All subjects were diagnosed with PTMC by thyroid fine-needle aspiration cytology (FNA) or pathology by core needle biopsy (CNB)

Summary

Introduction

Thyroid carcinoma has seen an incidence rising the fastest recently. Its major subtype is papillary thyroid microcarcinoma (PTMC) with a maximum diameter of 1.0 cm [1]. Conventional surgical procedures are preferrable for thyroid carcinoma. Most low-risk PTMC maintains stable, only progressive in rare cases [2]. It is feasible to perform microwave ablation (MWA) in lowrisk PTMC cases. Its application is doubted by potential tumor residues and lymphatic metastasis, MWA still exhibits higher safety and less trauma in its limited treatment of low-risk PTMC cases in China. We analyzed the efficacy and safety of MWA for PTMC, and postoperative morphology by core needle biopsy (CNB)

Methods

Results

Conclusion