Meta-Analysis of the Efficacy and Safety of Thermal Ablation for Treating Large Benign Thyroid Nodules

Xiaoyu Ji; Wei Sun; Chengzhou Lv; Jiapeng Huang; Hao Zhang

Disclosures

Clin Endocrinol. 2022;97(5):654-663. 

In This Article

Abstract and Introduction

Abstract

Objective: Many large benign thyroid nodules have symptoms and cosmetic problems. This study consisted of a meta-analysis to accurately assess the effect of thermal ablation on these nodules.

Methods: The PubMed, Embase, Web of Science, and Scopus databases were systematically searched for retrospective or prospective studies of thermal ablation since June 1, 2021. The weighted mean differences of the measures were analysed before and after treatment.

Results: A total of 10 eligible studies were included. By comparing the initial nodule volume with the nodular volume after thermal ablation, we found that the volume reduction rate was increased significantly after 1 month (SMD = 0.453, 95% CI: 0.323–0.583, p < .001), 3 months (SMD = 0.655, 95% CI: 0.563–0.747, p < .001), 6 months (SMD = 0.691, 95% CI: 0.607–0.774, p < .001), and 12 months (SMD = 0.694, 95% CI: 0.583–0.803), p < .001). The nodular volume was also found to decrease significantly, after 1 month (SMD = 2.381, 95% CI: 1.278–3.485, p < .001), 3 months (SMD = 5.071, 95% CI: 2.386–7.756, p < .001), 6 months (SMD = 5.363, 95% CI: 2.765–7.962, p < .001), and 12 months (SMD = 8.194, 95% CI: 2.113–14.274), p < .001). Symptom score (SMD = 4.419, 95% CI: 2.573–6.265, p < .001)and cosmetic score (SMD = 4.245, 95% CI: 2.566–5.359, p < .001) were reduced after thermal ablation.

Conclusions: Thermal ablation could become an alternative to manage large benign thyroid nodules.

Introduction

Thermal ablation is a kind of percutaneous ultrasound guidance that employs heat energy to directly cause irreversible damage or coagulative necrosis of tumour cells in the lesion tissue.[1] Various thermal ablation methods such as radiofrequency ablation (RFA), laser ablation (LA) and microwave ablation (MWA) have recently been deployed as non-surgical, minimally invasive treatments for thyroid nodules.[2] As a common proliferative disease, about 4%–7% of thyroid nodules are observed by physical examination, with a higher ultrasound detection rate of 30%–67%.[3] Although most nodules are benign, many of them exhibit symptoms of compression and appearance problems, requiring subsequent investigation. Numerous recent studies have shown that thermal ablation is an effective and safe technique to treat benign thyroid nodules.[4,5] The Italian guidelines for thyroid surgery emphasise the importance of thermal ablation in resolving clinical problems by reducing the size of nodules.[2] In addition, thermal ablation is recommended by some other mainstream guidelines, such as those of the American Association of Clinical Endocrinologists, the American College of Endocrinology, Association Medici Endocrinology (AACE/ACE/AME), and the Korean Society of Thyroid Radiology (KSTR).[6,7]

Large thyroid nodules have a volume of more than 13 ml.[8–10] These nodules are more prone to cause cosmetic issues or compression symptoms in the neck, including pain, dysphonia, foreign body sensation, discomfort, neck protrusion, and coughing. As a result, these large nodules require thermal ablation treatment.[11] However, because a large nodule occupies a vast space and is located close to vital structures, ablation difficulties are exacerbated even for skilled physicians, demonstrating that only one thermal ablation treatment rarely completely eliminates nodules. According to a study conducted at Mayo Clinic Center,[3] the unablated residue may expand and proliferate after one to two years, reintroducing compression symptoms such as foreign body sensation, coughing, or breathing difficulties, indicating that it does not fundamentally resolve the problem. Lim et al.[12] demonstrated that the volume of nodules increased by more than 50% compared to previous ultrasound, accounting for 5.6%. Sim et al. treated 54 patients with large thyroid nodules with thermal ablation and found that 13 cases recurred, resulting in a recurrence rate of 24.1%.[13]

Due to a limited number of patients, it is challenging to accurately assess the therapeutic benefit of thermal ablation on benign thyroid nodules. This study conducted a meta-analysis to obtain a more accurate evaluation of the therapeutic effect of thermal ablation in treating benign thyroid nodules.

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