Ultrasound-Guided Microwave Ablation for Benign Thyroid Nodules: A Retrospective Analysis of Safety and E cacy Factors

Baoying Xia West China Hospital of Sichuan University Boyang Yu West China Hospital of Sichuan University Xiaofei Wang West China Hospital of Sichuan University Yu Ma West China Hospital of Sichuan University Feng Liu West China Hospital of Sichuan University Yanping Gong West China Hospital of Sichuan University Xiuhe Zou West China Hospital of Sichuan University Jianyong Lei West China Hospital of Sichuan University Anping Su West China Hospital of Sichuan University Tao Wei West China Hospital of Sichuan University Jingqiang Zhu West China Hospital of Sichuan University Qiang Lu West China Hospital of Sichuan University Zhihui Li (  452863580@qq.com ) West China Hospital of Sichuan University


istic regress
on analysis showed that microwave ablation had a good effect on the initial volume of nodules less than or equal to 10 ml.Furthermore, the serum levels of triiodide thyroid hormone (T3), thyroxine (T4) and thyrotropin (TSH) were all within the normal range, indicating that microwave ablation would not impair thyroid function.

The therapeutic effect of microwave ablation has been proved clinically at home and abroad.It has a good therapeutic effect on benign thyroid nodules.Numerous studies have shown that the volume reduction ratio after microwave ablation can reach 24.0-51%, 54.8-75.1%,68.7-85.2%,75.8-96.4%

13][14] Our study showed similar outcomes.

Our results are consistent with those reported by Liu YJ, Yue W, Wu W et al. [13,15,16] , none of the patients treated with microwave ablation had s rious complications.Only one case of intrathyroid hemorrhage and postoperative hoarseness occurred in our study, but all recovered 2 months after the MWA.Hu et al. [12] found that 2.3% of the sound changes in the study followed microwave ablation, but all recovered within two weeks.Therefore, it can be seen that microwave ablation(MWA)for benign thyroid class has the characteristics of fewer complications and easier recovery.

In our study, Logistic regression analysis showed that the initial volume of nodules, especially small nodules (volume < 10 ml), was a risk factor for the effect of microwave ablation.Cesareo R et al. [17]   obtained similar results in their study, suggesting that ablation can effectively reduce benign thyroid nodules, especially small ones.Lee GM et al. [10] found that ablation wa

more effective in the
reatment of small nodules with a volume less than 4 ml.(P= 0.030) Heck K et al. [18] proposed that the serum levels of triiodothyroid hormone (T3), thyroxine (T4), thyrotrophin (TSH), thyroglobulin (Tg), anti-TG, thyrotrophin receptor (TRAb), and thyroid peroxidase (anti-TPO) showed no signi cant changes after the microwave ablation and the follow-up of half a year.Erturk MS et al. [19] pointed out that the effect of MWA on thyroid function had no signi cant difference at 6 months, but the effect was signi cant at 24 hours.In our study, we reached the same conclusion that the serum levels of triiodide thyroid hormone (T3), thyroxine (T4) and thyrotropin (TSH) after microwave ablation were all within the normal level and decreased compared with that before surgery.Therefore, we have reason to believe that microwave ablation h

a good effect a
d has no effect on thyroid function.

This study still has some limitations.First, this was a retrospective study, with no control group.Second, the follow-up time in this study was not long enough so that the volume reduction ratio reached a plateau value.Third, symptom scores and cosmetic scores were not used for quantitative evaluation.The

fore, long-term, quantita
ive and prospective studies are needed to further verify the conclusions in the future.



This retrospective study selected patients who underwent ultrasound guided microwave ablation of benign thyroid nodules at West China Hospital of Sichuan University from October 2018 to March 2020.The inclusion criteria were: (1)Consistent with the diagnosis of benign thyroid nodules (ultrasound, CT or ne needle aspiration); 2 These patients are in line with the indications of ultrasunion-guided microwave
Clinical dataablation for the treatment of benign thyroid nodules 3 Local residents or long-term residents of the cityand have good compliance. The exclusion criteria were: 1 Patients with con rmed thyroid cancer; 2Patients with benign thyroid nodules underwent surgical resection 3 Associated with severe di easeand a life expectancy of less than one year 4 Patients with poor compliance, unable to adhere to thereview.Data collectionCollect basic information of patients, including name, admission number, gender, age, etc. Preoperativebenign thyroid nodules, size, nature, duration of surgery, ablation power, complications, average length ofstay. The size of benign thyroid nodules and the levels of TSH, FT3 and FT4 in plasma at 1, 3, 6 and 12months after the operation.

Table 1 Table 1
11
Pro les of thyroid nodules treated with MWA
CharacteristicAll (N = 306)Percentage(%)Largest diameter (mm)33(4-70)Volume (ml)8.01(2.25-16.98)Locationupper

middle lobe 9731.70l
wer lobe11537.58Soliditycystic268.50Solid7825.49Mixed20266.01Volume(ml)v ≤ 1017858.17v > 1012841.83E cacy evaluation
information A total of 214 patients with benign thyroid nodule treated by microwave ablation were included in this study, including 31 males and 183 females.The median age was 45.84 ± 14.32(11-91)years.The duration of surgery for patients undergoing microwave ablation is approximately 7 minutes and 25 seconds and the average ablation power is 30.52(30-40)w, with an average length of stay of 2(1-7) days.The median follow-up time in this study was 10.12 ± 2.78 months.There were 148 cases of single nodules and 66 cases of multiple nodules.Benign thyroid nodule characteristicsIn this study, 306 thyroid nodules were ablated by microwave in 214 patients.The nodule had a median maximum diameter of 33 mm and a mean volume of 8.01 ml.The number of nodules in the lower thyroid lobe was the largest, accounting for 37.58%(115/306).The number of cystic nodules, solid nodules and mixed nodules was 26(8.50%),78(25.49%)and 202(66.01%),respectively.The volume of nodules (less than 10 mL) before microwave ablation was dominated by small nodules, accounting for 58.17% (178/306).(


Table 2
2VRR of different nodule types1 month3months 6months 12monthsTotal40.7960.3774.5985.60SolidityCystic46.646

7281.2188.1
Solid35.5958.1970.4684.08Mixed43.5062.2875.1186.24P value 0.0010.0080.1400.389Table 3Thyroid hormone changes during follow-up periodBefore1 month3 months6 months12 monthsP valueTSH2.24 ± 2.342.43 ± 1.942.65 ± 1.962.72 ± 1.542.78 ± 1.310.026(Mu/L)FT35.07 ± 1.404.77 ± 1.074.51 ± 1.624.32 ± 1.324.13 ± 0.730.445(pmol/L)FT417.09 ± 5.5216.09 ± 2.7115.64 ± 2.9115.08 ± 2.4414.83 ± 1.650.447(pmol/L)
Among 214 patients treated with MWA,none had serious complications.However, one patient developed intracapsular hemorrhage and recovered within a month.Another case developed recurrent laryngeal nerve injury but recovered within two months.

Availability of data and materialsThe datasets used and analyzed during the cu rent study are available from the corresponding author on reasonable request.FundingNot applicable.ConclusionIn summary, our study shows that ultrasound-guided microwave ablation is effective and safe in the treatment of benign thyroid nodules.In addition, microwave ablation has a good effect on different types of thyroid nodules (cystic, solid and mixed).Especially for the initial small olume of nodules, treatment is better.Microwave ablation(MWA) is characterized by better protection of thyroid function, fewer complications and superior esthetic results.In clinical practice, we suggest that ultrasound-guided microwave ablation should be the rst choice for the treatment of benign thyroid nodules.Declarations Ethics approval and consent to participateThis research based on the Declaration of Helsinki, and the study was approved by Ethics Committee on Biomedical Research, West China Hospital of Sichuan University (approval number: 2020599).Consent to publishWr tten informed consent for publication of their clinical details was obtained from all patients.Competing interestsThe authors have no competing interest to declare.AcknowledgementNot applicable.Authors' informationBaoying Xia and Boyang Yu contribute equally to this paper.A liations 1. Surgical Treatment center of Thyroid/Parathyroid Diseases, West China Hospital, Sichuan University(Chengdu 610041)
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