Thermal ablation of thyroid nodules: are radiofrequency ablation, microwave ablation and high intensity focused ultrasound equally safe and effective methods?

Comparison of ultrasound-guided microwave ablation, laser ablation, and radiofrequency ablation for the treatment of elderly patients with benign thyroid nodules: A meta-analysis

BACKGROUND

A new minimally invasive technique, ultrasound-guided thermal ablation has become one of the treatment methods for benign thyroid nodules. This study aims to evaluate the efficacy and safety of laser ablation (LA), radiofrequency ablation (RFA), and microwave ablation (MWA) in the treatment of elderly patients with benign thyroid nodules.

METHODS

PubMed, Web of Science, and Cochrane Library were searched for qualified randomized controlled studies (RCTs) issued from establishing databases to March 2022. After screening and evaluating the article quality, the data on nodular volume reduction rate (VRR) and the incidence of complications after thermal ablation were extracted and analyzed by RevMan 5.3 and Stata l4.0.

RESULTS

The meta-analysis included seven articles with 3055 participants. We found that LA, RFA, and MWA could markedly reduce the volume of benign thyroid nodules. LA was superior to RFA and MWA in reducing the volume of benign thyroid nodules in 6 months of follow-up (all P < 0.05). LA, RFA, and MWA can be safely implemented in patients with benign thyroid nodules. The incidence of significant complications after the RFA group was enhanced compared with that in the MWA (P < 0.05), and the incidence of secondary complications after RFA was slightly higher than that of LA (P < 0.05).

CONCLUSION

LA, RFA, and MWA can markedly reduce the volume of benign thyroid nodules in elderly patients and can safely treat benign thyroid nodules.

The effectiveness and safety of thermal ablation for thyroid carcinoma lymph node metastasis are affected by the diameter of metastatic lymph nodes: A meta-analysis

BACKGROUND

To explore the diameter of lymph nodes with metastatic thyroid carcinoma and the effectiveness and safety of thermal ablation.

METHODS

Several databases were searched for literature on the treatment of thyroid carcinoma metastatic lymph nodes by thermal ablation. A subgroup analysis was performed according to the diameter of the metastatic lymph nodes. The measures included pooled estimates of mean volume reduction, pooled proportions of total disappearance and recurrence, and the pooled proportions of overall complications.

RESULTS

There were 20 studies with 372 patients and 620 metastatic lymph nodes included. Based on the average maximum diameter of the metastatic lymph nodes, they were divided into three groups: A (≤ 10 mm), B (10 < diameter ≤ 20 mm), and C (> 20 mm). The study results indicated a significant decrease in the average volume only in groups A and B. The ratio of tumor disappearance showed that group A had the highest percentage, followed by group B and then group C. The recurrence rates were comparable between groups A and B, but slightly lower than in group C. Moreover, the overall complication rates for the three groups were ranked as follows: group A > group C > group B.

CONCLUSION

Overall, thermal ablation is an effective and safe treatment for thyroid cancer metastatic lymph nodes with diameters of 10-20mm.

Assessing the relative effectiveness of various ultrasound-guided ablation techniques for treating benign thyroid nodules: A systematic review and network meta-analysis

BACKGROUND

Benign thyroid nodules (BTNs) represent a prevalent clinical challenge globally, with various ultrasound-guided ablation techniques developed for their management. Despite the availability of these methods, a comprehensive evaluation to identify the most effective technique remains absent. This study endeavors to bridge this knowledge gap through a network meta-analysis (NMA), aiming to enhance the understanding of the comparative effectiveness of different ultrasound-guided ablation methods in treating BTNs.

METHODS

We comprehensively searched PubMed, Embase, Cochrane, Web of Science, Ovid, SCOPUS, and ProQuest for studies involving 16 ablation methods, control groups, and head-to-head trials. NMA was utilized to evaluate methods based on the percentage change in nodule volume, symptom score, and cosmetic score. This study is registered in INPLASY (registration number 202260061).

RESULTS

Among 35 eligible studies involving 5655 patients, NMA indicated that RFA2 (radiofrequency ablation, 2 sessions) exhibited the best outcomes at 6 months for percentage change in BTN volume (SUCRA value 74.6), closely followed by RFA (SUCRA value 73.7). At 12 months, RFA was identified as the most effective (SUCRA value 81.3). Subgroup analysis showed RFA2 as the most effective for solid nodule volume reduction at 6 months (SUCRA value 75.6), and polidocanol ablation for cystic nodules (SUCRA value 66.5).

CONCLUSION

Various ablation methods are effective in treating BTNs, with RFA showing notable advantages. RFA with 2 sessions is particularly optimal for solid BTNs, while polidocanol ablation stands out for cystic nodules.

Efficacy of HIFU for the treatment of benign thyroid nodules: a systematic review and meta-analysis

OBJECTIVE

Thyroid nodules are common and sometimes associated with cosmetic issues. Surgical treatment has several disadvantages, including visible scarring. High-intensity focused ultrasound (HIFU) is a recent noninvasive treatment for thyroid nodules. The present study aims to evaluate the effectiveness and safety of HIFU for the treatment of benign thyroid nodules.

METHODS

We searched PubMed, Embase, and Cochrane Library for studies evaluating the outcomes of HIFU for patients with benign thyroid nodules. We conducted a meta-analysis by using a random effects model and evaluated the volume reduction ratio, treatment success rate, and incidence of treatment-related complications.

RESULTS

Thirty-two studies were included in the systematic review. Only 14 studies were used in the meta-analysis because the other 18 involved data collected during overlapping periods. The average volume reduction ratios at 3, 6, and 12 months after treatment were 39.02% (95% CI: 27.57 to 50.47%, I2: 97.9%), 48.55% (95% CI: 35.53 to 61.57%, I2: 98.2%), and 55.02% (95% CI: 41.55 to 68.48%, I2: 99%), respectively. Regarding complications, the incidences of vocal cord paresis and Horner's syndrome after HIFU were 2.1% (95% CI: 0.2 to 4.1%, I2: 14.6%) and 0.7% (95% CI: 0 to 1.9%, I2: 0%), respectively.

CONCLUSIONS

HIFU is an effective and safe treatment option for patients with benign thyroid nodules. However, the effects of HIFU on nodules of large sizes and with different properties require further investigation. Additional studies, particularly randomized controlled trials involving long-term follow-up, are warranted.

CLINICAL RELEVANCE STATEMENT

Surgical treatment for thyroid nodules often results in permanent visible scars and is associated with a risk of bleeding, nerve injury, and hypothyroidism. High-intensity focused ultrasound may be an alternative for patients with benign thyroid nodules.

KEY POINTS

• The success rate of HIFU treatment for thyroid nodules is 75.8% at 6 months. Average volume reduction ratios are 48.55% and 55.02% at 6 and 12 months. • The incidence of complications such as vocal fold paresis, Horner's syndrome, recurrent laryngeal nerve palsy, hypothyroidism, and skin redness is low. • HIFU is both effective and safe as a treatment for benign thyroid nodules.

Comparison of the efficacy and safety of ultrasound-guided radiofrequency ablation and microwave ablation for the treatment of unifocal papillary thyroid microcarcinoma: a retrospective study

PURPOSE

This study aimed to compare the efficacy and safety of ultrasound-guided RFA and MWA in the treatment of unifocal PTMC.

METHODS

This retrospective study included 512 patients with 512 unifocal papillary thyroid microcarcinomas (PTMCs) who underwent RFA (n = 346) and MWA (n = 166) between January 2021 and December 2021. The volumes of the ablation areas were measured during follow-up, and the volume reduction rates were evaluated. The ablation duration, volume of hydrodissection, and ablation-related complications were also compared between the groups.

RESULTS

All lesions received complete ablation and no local or distant recurrences were observed in the two groups. A larger volume of isolation liquid was used for RFA than for MWA (p = 0.000). Hoarseness occurred in seven patients who underwent RFA (p = 0.102). At the 1-week follow-up, the mean volume of the areas ablated by RFA was smaller than that of the areas ablated by MWA (p = 0.049). During follow-ups at months 3, 9, 12, 15, and 18, the mean volumes of the ablated areas were larger in the RFA group than in the MWA group (all, p < 0.05). The mean volume of the ablated lesions increased slightly at the 1-week follow-up and then decreased at 1 month after ablation in both groups. The absorption curve of the ablated lesions in the RFA group was similar to that in the MWA group.

CONCLUSIONS

RFA and MWA are both efficient and safe methods for treating unifocal PTMC. They may be alternative techniques for patients who are not eligible or are unwilling to undergo surgery.

Thyroid Nodules: Emerging Trends in Detection and Visualization based on Citespace

BACKGROUND

Thyroid nodule (TN) is a highly prevalent clinical endocrine disease. Many countries have formed guidelines on the prevention and treatment of TN based on extensive research. However, there is a scarcity of TN-related literature based on bibliometrics.

OBJECTIVES

This study aimed to evaluate the scientific achievements and progress of TN research from a global perspective by investigating the literature for 20 years through bibliometrics.

METHODS

We searched the literature on TN in the core collection of the Web of Science database from 2002 to 2021 and used the Citespace software to analyze the co-authorship, co-citation, and co-occurrence of countries, institutions, authors, keywords, and co-cited literature.

RESULTS

We retrieved 12319 documents related to TN. The literature on TN has been growing since 2002. The United States has contributed the largest proportion of TN papers (20.64%), followed by China, Italy, and South Korea. The United States ranked first in terms of centrality (0.38). Haugen BR, Gharib H, and Cibas ES are the top three most cited authors. The papers published in Thyroid were cited most frequently (7952 times). The most prominent keywords were management, cancer, fine needle aspiration, diagnosis, malignant tumor, thyroid cancer, ultrasound, biopsy, benign, surgery, ablation, and cytology. All keywords could be divided into three categories: diagnosis stratification, treatment, and cancer. As far as potential hot spots are concerned, the keywords that have recently burst strongly and are still continuing are: "Association Guideline" (2018-2021), "Radiofrequency Ablation" (2017-2021), "Classification" (2019-2021), and "Data System" (2017-2021).

CONCLUSION

Based on the current trends, the number of publications on TN will continue to increase. The United States is the most active contributor to research in this field. Previous literature focused on stratification, cancer, surgery, and ablation, and there were different opinions on the stratification of diagnosis. There were relatively few studies on pathogenesis and treatment using medicine. More focus will be placed on association guidelines, radiofrequency ablation, classification, and data system, which may be the next popular topics in TN research.

High-intensity focused ultrasound for benign thyroid nodules: Systemic review and meta-analysis

BACKGROUND

High-intensity focused ultrasound (HIFU) is a less invasive option offered for the treatment of large, compressive, benign thyroid nodules.

METHODS

Observational studies of more than five participants using HIFU in the management of benign thyroid nodules from 2000 to 2021 were identified using predefined inclusion criteria. The primary outcome was an estimate of the effectiveness of HIFU.

RESULTS

Out of 158 studies reviewed, 8 articles were included with 297 patients and 300 nodules. HIFU significantly reduced nodule volume from 1 to 24 months following therapy (weighted mean difference [WMD], 47.68, 95 % confidence interval [CI], 34.13-59.66, p < 0.0001) and achieved favorable success rates (risk ratio [RR], 1.49, 95 % CI, 1.15-1.84, p < 0.001) for 50 % volume reduction.

CONCLUSIONS

HIFU appears to be a feasible, safe, and effective treatment modality for patients with benign thyroid nodules. Future research, including randomized controlled trials, is needed to determine therapy optimization, and patient selection to identify the potential role of this new therapy.

Comparison of the Efficiency of Radiofrequency and Microwave Ablation Methods in the Treatment of Benign Thyroid Nodules

RATIONALE AND OBJECTIVES

To compare the efficacy of two thermal ablation techniques (radiofrequency vs microwave ablation) in the treatment of benign thyroid nodules.

MATERIALS AND METHODS

A total of 80 patients with 80 nodules underwent thermal ablation of thyroid nodules with either radiofrequency ablation (RFA) (23 females and 14 males; mean age 41 ± 9years) or microwave ablation (MWA) (28 females and 15 males; mean age 45 ± 11years). Ultrasound assessments were made at the 1st, 3rd, 6th, and 12th months after the ablation procedure.

RESULTS

The mean initial volume of the nodules (RFA: 15.6 mL [min 2.5-max 74]; MWA: 40 mL [min 2-max 205]) was statistically significantly different (P < .001). The following were the volume reduction rates of nodules at 1, 3, 6, and 12months, respectively: after RFA: 46.8 ± 13.5%, 62.9 ± 13.6%, 71.6 ± 11.9%, and 77.9 ± 10.3%. After MWA: 38.7 ± 12.5%, 54 ± 15.3%, 59.6 ± 12.5%, and 65 ± 11.3%. For all months, volume reduction rates in the RFA group were significantly higher than those in the MWA group (P < .05). One patient treated by RFA reported an abscess formation and another patient treated by RFA had a self-limiting hematoma, who recovered without any further treatment. Also, in the MWA group, one patient had abscess formation and another patient had transient recurrent nerve paralysis, who recovered with appropriate treatment.

CONCLUSION

Both methods are effective in treating benign thyroid nodules; however, RFA provides a better volume reduction.

Minimally Invasive Treatments of Benign Thyroid Nodules: A Network Meta-Analysis of Short-Term Outcomes

Background: Image-guided thermal ablation interventions are novel thermal-based modalities used for the treatment of benign thyroid nodules. Methods: We conducted a systematic review and a Bayesian network meta-analysis, examining studies using thermal ablation interventions in the treatment of benign nodular thyroid disease (PROSPERO CRD42022367680). The primary endpoints included volume reduction rate (VRR), and symptomatic score and cosmetic score improvement. Secondary endpoints included vocal disturbances, laryngeal nerve palsy, hypothyroidism, and nodular regrowth (defined by increased nodular volume of >50% for thermal ablation or new nodules arising in remaining thyroid tissue conventional surgery [CS]). Results: We included 16 studies (3 randomized controlled trials [RCTs] and 13 comparative case series), describing radiofrequency ablation (RFA), laser ablation (LA), microwave ablation (MWA), high-intensity focus ultrasound (HIFU), and CS, respectively. The review included data from 4112 patients followed for a mean of 11.9 months. Meta-analyses showed no significant differences among RFA, LA, MWA, HIFU, and CS regarding any of the primary endpoints of VRR, symptomatic score, and cosmetic score. In examining the surface under the cumulative ranking area (SUCRA) ranking, CS (SUCRA, 98.49), LA (SUCRA, 51.58), and MWA (SUCRA, 57.0) were identified as the three interventions that were most likely to result in the largest VRR, symptomatic and cosmetic score reduction. RFA, relative risk (RR) 0.19 [95% credibility interval (CI): 0.06 to 0.48], LA RR 0.23 [CI: 0.06 to 0.79], and MWA RR 0.25 [CI: 0.09 to 0.60] were associated with the greatest reduction in risk for postintervention vocal complications compared with CS, with RFA (SUCRA, 61.62) being ranked as the highest in safety. RFA RR 0.05 [CI: 0.00 to 0.40] and MWA RR 0.16 [CI: 0.02 to 0.73] were associated with a reduced risk of transient laryngeal nerve injury compared with CS. RFA RR 0.00 [CI: 0.00 to 0.00] and MWA RR 0.00 [CI: 0.00 to 0.03] were associated with a reduced risk of hypothyroidism occurrence compared with CS, with RFA (SUCRA, 99.86) yielding the highest safety ranking. RFA was associated with a reduced risk for nodular regrowth RR 0.09 [CI: 0.00 to 0.85], compared with CS. Conclusion: We have comprehensively reviewed the published literature on the efficacy and safety of thermal ablation modalities for benign thyroid nodules. Important research gaps remain regarding a paucity of both long-term data and high-quality RCTs.

Development and validation of a nomogram model for predicting residue of partially cystic thyroid nodules after ultrasound-guided ethanol and thermal ablation

OBJECTIVES

To develop and validate a nomogram model for predicting residue of partially cystic thyroid nodules (PCTNs) after ethanol and thermal ablation.

MATERIALS AND METHODS

From July 2015 to August 2022, a total of 97 patients (age 40.78 ± 12.61 years) with 107 treated benign PCTNs receiving ethanol and thermal ablation were enrolled. Pre-ablative laboratory test results and the ultrasound (US) and contrast-enhanced ultrasound (CEUS) features of lesions were collected. They were categorized into non-residue group and residue group according to the CEUS examination assessment after ablation. Univariate and multivariate logistic regression analysis were adopted to build a nomogram. The nomogram was validated by internal stratified fivefold cross-validation. The calibration, discrimination and clinical utility of the nomogram were investigated to assess the performance of the model.

RESULTS

Residue was reported in 30 out of 107nodules (28.0%). Multivariate logistic regression analysis revealed initial volume (OR=1.12, 95%CI 1.06-1.19) and presence of septum (OR=3.19, 95%CI 1.09-9.36) were predictors of residue of PCTNs. The nomogram developed by the above factors showed good calibration and discrimination. The area under the curve (AUC), sensitivity and specificity of this model were 0.832, 86.7% and 68.8%, respectively. When applied to internal validation, the model revealed good generalizability with stratified fivefold cross-validation in the cohort (mean AUC = 0.821).

CONCLUSIONS

The nomogram model has good performance for predicting the residue of PCTNs undergoing ethanol and thermal ablation. This could play a role in the decision of treatment and follow-up in clinical practice.

The influence of thyroid hormone medication on intra-therapeutic half-life of 131I during radioiodine therapy of solitary toxic thyroid nodules

Despite a significantly improved dietary iodine supply, solitary toxic thyroid nodules (STN) are still a common clinical problem in former iodine deficient areas. Radioiodine treatment (RIT) is a well-established therapeutic option with few side effects and high success rates. As radioiodine biokinetics are individual for every patient, the necessary activity has to be calculated individually by a pre-therapeutic measurement of the intra-therapeutic effective half-life (EHL) in a radioiodine uptake test (RIUT). A suppressive medication with triiodothyronine (T3) or tetraiodothyronine (T4) is often needed to suppress uptake in normal thyroid tissue. Therefore, the aim of this study was to quantify the possible influence of this medication on intra-therapeutic radioiodine biokinetics. A cohort of 928 patients with STN undergoing RIUT and RIT was analysed. Patients were subdivided into 3 groups. Group T3: medication with T3 (n = 274), group T4: medication with T4 (n = 184) and group NM: no additional medication (n = 470). The T3 and T4 subgroups were further subdivided depending on the dose of thyroid hormone medication. In order to analyse the influence of thyroid hormone medication on individual intra-thyroidal biokinetics, the variance of the determined individual EHL between RIUT and RIT within the single groups and within the subgroups was investigated. EHL was significantly decreased between RIUT and RIT in the T3 and T4 subgroups (EHL: T3: 5.9 ± 1.1 d in RIUT and 3.3 ± 1.4 d in RIT (− 43%) (p < 0.05); T4: 5.9 ± 1.2 d in RIUT and 3.4 ± 1.5 d in RIT (− 42%) (p < 0.05). The decrease of EHL did not differ statistically between T3 or T4. However, both showed a highly significant difference compared to the NM group (p < < 0.05). A further subgroup analysis showed a significant dependence of the decrease in EHL related to the dose of thyroid hormone medication of 35–58% (T3) and 15–67% (T4) (p < 0.05). A significantly reduced EHL compared to RIUT in patients receiving thyroid hormone medication was detected. Moreover, a significant correlation between the dose of thyroid hormone medication (T3 or T4) and the decrease of EHL was found. Therefore, an adaption of the calculated activity should be considered in RIUT to obtain the required radiation dose in RIT of patients suffering from STN.

Total thyroidectomy versus hemithyroidectomy with intraoperative radiofrequency ablation for unilateral thyroid cancer with contralateral nodules: A propensity score matching study

Background

For unilateral papillary thyroid carcinoma (PTC) patients with contralateral benign nodules, optimal treatment decisions are made according to patient preference and the disease’s pathological features. This study was performed to evaluate the efficacy and complications of hemithyroidectomy with intraoperative radiofrequency ablation (RFA) compared with total thyroidectomy.

Methods

Patients with unilateral PTC and cytologically benign contralateral nodules were enrolled from 2014 to 2018. Total thyroidectomy or hemithyroidectomy with intraoperative RFA of the contralateral nodule was offered to patients who had anxiety regarding their disease. The operation-related parameters, transient or permanent nerve injury, hypocalcemia and disease recurrence, were recorded and compared between the two groups.

Results

After propensity score matching, 191 patients who underwent total thyroidectomy and 224 contralateral nodules in 191 patients underwent hemithyroidectomy with intraoperative RFA (HTRFA) were included. The volume reduction ratios of the contralateral nodules were 67.7% at 12 months and 95.8% at 24 months. The total thyroidectomy group reported significantly higher hypocalcemia than HTRFA within one year (7.8% vs. 2.6%, p = 0.022). Supplemental levothyroxine was not required in 28.3% (54/191) of the patients one year after HTRFA. With a median follow-up of 4.1 years, three recurrences (1.6%) were observed in the HTRFA, and no recurrence occurred in the total thyroidectomy group (p = 0.246).

Conclusions

Hemithyroidectomy for unilateral PTC and intraoperative RFA for contralateral nodules were acceptable and effective treatment approaches and did not increase the risk of complications.

Graphical Abstract

Effectiveness of High-intensity Focused Ultrasound (HIFU) Therapy of Solid and Complex Benign Thyroid Nodules - A Long-term Follow up Two-center Study

PURPOSE

To investigate the effectiveness of high-intensity focused ultrasound (HIFU) of solid and complex benign thyroid nodules.

METHODS

Fifty-eight patients with benign thyroid nodules were treated with HIFU at two centers from 2014-2019. The device, EchoPulse (Teraclion, Malakoff, France), heats the nodes to 80-90 °C. Nodal volumes were measured by ultrasound at regular intervals before and up to 12 months after therapy. In a retrospective long-term two-center study, average volume reductions in relation to baseline volume were statistically analyzed by the Wilcoxon signed-rank test. Side effects were documented.

RESULTS

In solid nodules, the average percent volume reductions at the 3, 6, 9, and 12-months follow-up were 49.98%, 46.40%, 65.77%, and 63.88%, respectively. The results were significant with p<0.05 in the Wilcoxon signed-rank test at the 3, 6, and 9-months follow-up. In complex nodules, the average percent volume reduction was 35.2% at 3 months, 36.89% at 6 months, and 63.64% at twelve months follow up. The results were significant with p<0.05 in the Wilcoxon signed-rank test at the 3- and 6-months follow-up. The complication rate was 5.2%. All complications occurred in patients with solid nodules.

CONCLUSION

The study showed that HIFU is an effective treatment method for both solid and complex nodules. The complication rate is relatively high at 5.2%. No long-term complications occurred. The solid nodules responded better to HIFU than complex nodules.

Microwave Ablation Vs Traditional Thyroidectomy for Benign Thyroid Nodules: A Prospective, Non-Randomized Cohort Study

RATIONALE AND OBJECTIVES

To evaluate the efficacy of microwave ablation (MWA) for benign thyroid nodules (BTNs) and compare trauma and complication rates between MWA and traditional thyroidectomy for BTNs.

MATERIALS AND METHODS

84 patients with BTNs were recruited and followed up at 1, 3, 6, and 12months. 56 and 28 patients chose to undergo MWA (group A) and traditional thyroidectomy (group B), respectively. Efficacy was assessed by volume reduction rate (VRR) and therapeutic success rate (TSR) at each follow-up. Trauma was compared using inflammation response parameters, visual analog scale (VAS) scores, quality of life (QOL) and thyroid function measures at 1, 3, and 6 months. Complications rates were also compared.

RESULTS

The VRR was 80.70 ± 18.60%, and TSR was 91.70% at 6-months. Furthermore, the VRR increased to 90.45 ± 11.51%, and TSR increased to 100% at 12-months. C-reactive protein levels were significantly higher in group B on the first postoperative day (POD) (3.89 ± 0.86 mg/mL vs 3.39 ± 0.56 mg/mL, p = 0.002). Visual analog scale scores were significantly lower in group A on the first and second POD. Thyroid stimulating hormone levels were significantly lower in group A at three (1.71 ± 1.12uIU/mL vs 2.37 ± 1.24uIU/mL, p = 0.013) and 6-months (1.34 ± 0.70uIU/mL vs 1.97 ± 0.94uIU/mL, p = 0.002). There were no significant between-group differences in QOL and complication rates.

CONCLUSION

Microwave ablation shows acceptable and promising efficacy. Compared with thyroidectomy, MWA was associated with less trauma and comparable complication rates.

High intensity focused ultrasound in the therapy of benign thyroid nodules-first German bicentric study with long-term follow-up

PURPOSE

The study evaluated high-intensity-focused ultrasound (HIFU) for benign thyroid nodules in terms of efficiency, complication rate, influence of preablative nodule size, parameters influencing the therapeutic success and hormonal-thyroid-function.

METHODS

Seventy-two patients with 75 nodules were treated with HIFU at 2 centers from 2014-2019. Median nodule volume was 4.4 ml (range 0.33-53). The therapeutic ultrasound probe (EchoPulse THC900888-H) generated 80-90 °C in the target tissue with 87.6-320.3 J per sonication. Nodal volume was measured at baseline and over 12 months after therapy in a retrospective bicentric-study with long-term follow-up. Hormonal-thyroid function (TSH, T3, T4) was measured before and after ablation. Complications were assessed.

RESULTS

Significant volume reduction (p < 0.05 Wilcoxon-signed-rank test) of thyroid nodules was 38.98% at 3 months, 37.32% at 6 months, 61.54% at 9 months and 60.66% at 12 months. Volume reduction of nodules <3 ml did not differ significantly from nodules >3 ml (p > 0.05 Mann-Whitney test). At 3 months solid nodules had a significant volume reduction of 52.08%, complex nodules of 32.57%, nodules treated under regional anesthesia of 33.07% and under general anesthesia of 49.47%. Hormonal-thyroid function was not influenced significantly by HIFU therapy (p > 0.05 Wilcoxon-signed-rank test). Complication rate was 3.8%. No long-term complications occurred.

CONCLUSION

Significant volume reduction of thyroid nodules up to 12 months after HIFU was shown. All complications were reversible. Therapy was more efficient in solid than complex nodules and in nodules treated under general anesthesia than with regional anesthesia. Hormonal-thyroid-function was not affected.

TRIAL REGISTRAFTION NUMBER

2020-1728-evBO. Date of registration: 16.06.2020. Agency: Ethik-Kommission bei der Landesäztekammer Hessen.

Thermal shielding performance of self-healing hydrogel in tumor thermal ablation

Thermal ablation therapy is widely used in the surgical treatment of tumors. Clinically, normal saline is generally used as an insulator to protect adjacent tissues from local high-temperature burns caused by thermal ablation. However, the flow of saline causes fluid loss, requiring frequent injections and complex operation, which is easy to lead to complications such as secondary injury and hematoma. Here, a self-healing chitosan-PEG (CP) hydrogel was proposed as a protective medium to challenge the clinical preparations. Compared with saline and non-self-healing hydrogel F127, CP hydrogel exhibited outstanding thermal shielding performance in the thermal ablation of thyroid nodule in a Beagle dog model. The transient plane source (TPS) method is used to measure thermal properties, including thermal conductivity, thermal diffusivity and specific heat capacity. The thermal shielding mechanism and clinical advantages including operability, biodegradability, and biological safety of self-healing hydrogel are then revealed in-depth. Therefore, self-healing hydrogel can achieve much better thermal management in tumor thermal ablation.

Safety and Efficacy of Ultrasound-Guided Radiofrequency Ablation for Benign Nonfunctional Thyroid Nodules in Children: A Retrospective Study of 62 Patients with Over Four Years of Follow-Up

Background: Image-guided radiofrequency ablation (RFA) for benign nonfunctional thyroid nodules in adults has been shown to be effective and safe, but few trials address the use of RFA in children. Therefore, this study was designed to assess the efficacy and safety of RFA application to benign nonfunctional thyroid nodules in children. Methods: A retrospective study of RFA for 70 benign nonfunctional thyroid nodules in 62 children with four-year follow-up was conducted. Volume reduction ratio (VRR), technique efficacy, regrowth rate, symptom score, and cosmetic score were calculated to evaluate the efficacy. Complications and side effects were recorded. Logistic regression analysis was performed to identify risk factors, and subgroup analyses were performed. Results: Patients were followed up for at least four years (59.1 ± 10.5 months, range 48-85 months). After RFA treatment, the VRR and technique efficacy rates were highest at the first year^* (77.5% and 91.4%, respectively) but decreased by four years (55.1% and 81.4%, respectively). The symptom score decreased from 4.0 ± 2.1^* to 0.8 ± 1.6 (Z = -6.82, p < 0.001), and the cosmetic score decreased from 3.3 ± 0.7 to 1.3 ± 0.9 (Z = -7.0, p < 0.001).^* The nodule regrowth rate was 22.9%, of which 56.3% of cases represented loss of efficacy. In the cases of loss of efficacy, 66.7% had greater volume than their initial presentation. Patients who received a second RFA treatment due to loss of efficacy lost efficacy again. Bilateral nodules, low vascularity, and low cystic components were independent risk factors correlating with technique efficacy. Bilateral nodules correlated with low VRR, low efficacy rate, and high regrowth rate. Nodules with a higher proportion of cystic components had higher VRR. The overall complication rate was 4.8%. Conclusions: RFA was effective in reducing the volume of benign nonfunctional thyroid nodules in children, providing significant symptomatic relief with a good safety profile during short- and long-term follow-up. RFA is a good minimally invasive treatment modality for selected pediatric patients, and it may not be appropriate for the treatment of bilateral thyroid nodules in children.

American Association of Clinical Endocrinology Disease State Clinical Review: The Clinical Utility of Minimally Invasive Interventional Procedures in the Management of Benign and Malignant Thyroid Lesions

OBJECTIVE

The objective of this disease state clinical review is to provide clinicians with a summary of the nonsurgical, minimally invasive approaches to managing thyroid nodules/malignancy, including their indications, efficacy, side effects, and outcomes.

METHODS

A literature search was conducted using PubMed and appropriate key words. Relevant publications on minimally invasive thyroid techniques were used to create this clinical review.

RESULTS

Minimally invasive thyroid techniques are effective and safe when performed by experienced centers. To date, percutaneous ethanol injection therapy is recommended for recurrent benign thyroid cysts. Both ultrasound-guided laser and radiofrequency ablation can be safely used for symptomatic solid nodules, both toxic and nontoxic. Microwave ablation and high-intensity focused ultrasound are newer approaches that need further clinical evaluation. Despite limited data, encouraging results suggest that minimally invasive techniques can also be used in small-size primary and locally recurrent thyroid cancer.

CONCLUSION

Surgery and radioiodine treatment remain the conventional and established treatments for nodular goiters. However, the new image-guided minimally invasive approaches appear safe and effective alternatives when used appropriately and by trained professionals to treat symptomatic or enlarging thyroid masses.

Charge Reversal Polypyrrole Nanocomplex-Mediated Gene Delivery and Photothermal Therapy for Effectively Treating Papillary Thyroid Cancer and Inhibiting Lymphatic Metastasis

As a traditional treatment for papillary thyroid cancer (PTC), surgical resection of diseased tissues often brings lots of inconveniences to patients, and the tumor recurrence and metastasis are difficult to avoid. Herein, we developed a gene and photothermal combined therapy nanosystem based on a polypyrrole (Ppy)-poly(ethylene imine)-siILK nanocomplex (PPR_ILK) to achieve minimally invasive ablation and lymphatic metastasis inhibition in PTC simultaneously. In this system, gelatin-stabilized Ppy mainly acted as a photothermal- and photoacoustic (PA)-responsive nanomaterial and contributed to its well-behaved photosensitivity in the near-infrared region. Moreover, gelatin-stabilized Ppy possessed a charge reversal function, facilitating the tight conjunction of siILK gene at physiological pH (7.35-7.45) and its automatic release into acidic lysosomes (pH 4.0-5.5); the proton sponge effect generated during this process further facilitated the escape of siILK from lysosomes to the cytoplasm and played its role in inhibiting PTC proliferation and lymphatic metastasis. With the guidance of fluorescence and PA bimodal imaging, gene delivery and Ppy location in tumor regions could be clearly observed. As a result, tumors were completely eradicated by photothermal therapy, and the recurrences and metastases were obviously restrained by siILK.

Effects of Regional and General Anesthesia on the Therapeutic Outcome of Benign Thyroid Nodules Treated with High Intensity Focused Ultrasound (HIFU)

BACKGROUND

The study investigated whether anesthesia performed during high-intensity-focused-ultrasound treatment (HIFU) of benign thyroid nodules influenced the therapy outcome, based on volume reduction and the amount of energy delivered.

METHODS

Thirty patients with benign thyroid nodules were treated with HIFU under general or regional anesthesia at two centers from 2014 to 2019. During HIFU, a therapeutic ultrasound probe, EchoPulse (Teraclion, Malakoff, France), heats the focus to 80-90 degrees Celsius. Nodal volumes were measured by ultrasound before and 3 months after therapy. For statistical analysis, the total population was divided into two groups according to the anesthesia performed. In a retrospective long-term multicenter study, volume reduction and the energy delivered were analyzed using the Wilcoxon signed-rank test and the Mann-Whitney test.

RESULTS

At three months follow-up, the total study population had an average volume reduction of 39.26% (range 4.03-91.16%, p < 0.001, n = 30), the general anesthesia group of 47.46% (range 13.64-91.16%, p = 0.001, n = 15) and the regional anesthesia group of 31.06% (range 4.03-68.63%, p = 0.001, n = 15). Under regional anesthesia a median energy of 3.16 kJ/cm³ (range: 0.96 - 8.2 kJ/cm³) and under general anesthesia a median energy of 0.88 kJ/cm³ (range: 0.18 - 1.63 kJ/cm³) were delivered. All results were significant with p < 0.05. The complication rate was 6.67%.

CONCLUSION

HIFU is an effective method to treat benign thyroid nodules. Comparing anesthesia methods, volume reduction is higher in patients treated under general anesthesia and less energy has to be delivered under general anesthesia.

TRIAL REGISTRATION NUMBER

2020-1728-evBO.

AGENCY

Ethik-Kommission bei der Landesäztekammer Hessen.

Pathology confirmation of the efficacy and safety of microwave ablation in papillary thyroid carcinoma

BACKGROUND

The incidence of papillary thyroid carcinoma (PTC) has rapidly increased in recent years. Microwave ablation (MWA) was proposed as an alternative treatment for PTC. This study aimed to investigate the efficacy and safety of MWA by exploring the postoperative pathology results of post-ablation lesions in patients with PTC.

METHODS

This study retrospectively analyzed data from 12 patients who underwent thyroid surgery after MWA treatment for primary PTC between January 2015 and November 2021 in six hospitals.

RESULTS

The average age of the 12 patients (8 female) was 45.3 ± 9.7 years. There was one patient with PTC (size > 1 cm) and 11 patients with micro-PTC (size ≤ 1 cm), of which eight patients had unifocal micro-PTC and three patients had multifocal micro-PTC. A total of 17 tumor foci with mean size of 6.2 ± 2.6 mm were treated by MWA. The median interval time between MWA and surgery was 6.6 months (range: 0.4-21.9 months). Intraoperatively, adherence to the anterior cervical muscle group was observed in three cases (3/12). Upon postoperative pathologic examination, all the post-ablation lesions of the eight unifocal micro-PTC and two multifocal micro-PTC showed no residual carcinomas. Outside the ablation zone, PTCs were detected in three cases, including two of the eight patients with unifocal micro-PTC and one of the three patients with multifocal micro-PTC. Cervical lymph node metastases were detected in seven patients (7/12).

CONCLUSION

MWA was feasible for the treatment of primary unifocal low-risk micro-PTC (T1aN0M0) with good efficacy and safety. However, the use of MWA for treating PTC (size > 1 cm) and multifocal micro-PTC remains controversial.

Ultrasound-Guided Thermal Ablation of Thyroid Nodules: Technicalities Progress and Clinical Applications, Especially in Malignant Thyroid Nodules

Thyroid nodules are commonly encountered in health care practice. They are usually benign in nature, with few cases being malignant, and their detection has increased in the adult population with the help of ultrasonography. Thyroidectomy or surgery is the first-line treatment and traditional method for thyroid nodules; however, thyroidectomy leaves permanent scars and requires long-term use of levothyroxine after surgery, which makes patients more reticent to accept this treatment. Thermal ablation is a minimally-invasive technique that have been employed in the treatment of benign and malignant thyroid nodules nodules, and have been shown to be effective and safe. Several studies, including long-term, retrospective, and prospective studies, have investigated the use of ablation to treat benign thyroid nodules and malignant thyroid nodules, including papillary thyroid carcinoma. Here, we review the recent progress in thermal ablation techniques for treating benign and malignant nodules, including their technicalities, clinical applications, pitfalls and limitations, and factors that could affect treatment outcomes. Special in-depth elaboration on the recent progress of the application of thermal ablation therapy in malignant thyroid nodules.

Ultrasound guided microwave ablation of thyroid nodular goiter and cystadenoma: A single center, large cohort study

Thyroid nodules are one of the most common entities that affect the thyroid gland. Traditionally, their treatment was surgery. Currently, ablation combination with percutaneous procedure became a good option.To analyze safety, efficacy, and describe our experience in microwave-ablation using ultrasound-guidance for benign thyroid nodules.A total of 304 patients with 1180 thyroid nodules (thyroid cystadenoma and nodular goiter) were studied retrospectively. Two hundred sixty-seven patients who underwent microwave-ablation successfully in our hospital were enrolled in this study. The baseline, follow-up nodule volume, thyroid function tests, thyroid antibodies, and posttherapy complications were analyzed. The informed written consent was obtained from patients or guardians. The study was approved by the ethics committee of our hospital.The average age was 50.1 ± 11.7 (21-83 years), 214 were women (80.1%) and 53 (19.9%) were men. The average number of nodules per patient was 4.02 ± 1.8 (1-8), 9.86%, 6.13%, and 84% located in the right thyroid lobe, left lobe, and bilateral, respectively. The average size of the nodules was 5.28 cm2 ± 3.63 (0.09-23.45 cm2). The average ablation time was 11 minutes ± 5.36 (3-20 minutes). The hospitalization period was 24 hours ± 10.16 (7-48 hours). Eighteen complications were reported. Postablation volume reduction rate was 54.74% and 93.3% at 3 and 12 months follow-up respectively (P < .05). The thyroid function tests, pre and postablation showed no significant changes (P > .05).Ultrasound-guided microwave-ablation of thyroid nodules is safe and effective. More clinical trials are needed to define the true use of microwave-ablation.

Safety and Efficacy of Radiofrequency Ablation of Thyroid Nodules-Expanding Treatment Options in the United States

CONTEXT

Radiofrequency ablation (RFA) has only recently gained popularity in the United States for treatment of thyroid nodules (TNs), with a limited number of patients having undergone the procedure in this country.

OBJECTIVE

To evaluate the safety and efficacy of RFA of TNs performed in an outpatient setting in the United States.

METHODS

This is a retrospective, single-center study of 53 patients who underwent RFA of 58 TNs between November 2018 and January 2021. The reduction in volume of nodule, cosmetic and symptomatic improvement, effect on thyroid function, and complications following RFA were assessed.

RESULTS

Eleven out of 53 patients were excluded from the analysis. A total of 47 benign TNs (23 nonfunctioning thyroid nodules [NFTNs] and 24 autonomously functioning thyroid nodules [AFTNs]), were assessed after RFA. The median reduction in volume was 70.8% after a median follow-up period of 109 days, with symptomatic and cosmetic improvement (P < 0.0001). Compared with larger nodules, smaller nodules had greater volume reduction (P = 0.0266). RFA improved thyrotropin (TSH) in AFTNs (P value = 0.0015) and did not affect TSH in NFTNs (P value = 0.23). There were no major complications; however, 1 patient had self-limited local bleeding and another had transient voice change that recovered in 6 months.

CONCLUSION

RFA is a safe and efficacious treatment for symptomatic NFTNs and AFTNs in our population and is especially effective for smaller nodules. RFA should be considered an alternative for TNs in patients who cannot or do not want to undergo surgery.

Noninvasive thyroid histotripsy treatment: proof of concept study in a porcine model

INTRODUCTION

This study was performed to determine the feasibility and safety of creating superficial histotripsy treatment in a live porcine thyroid model.

METHODS

The porcine thymus comparable in size, shape and location to the human thyroid was used for this study. This model has been used for thyroid surgery studies due to the diminutive size of the porcine thyroid. Four female swine underwent a total of eight histotripsy treatments performed with a prototype therapy system (HistoSonics, Inc., Ann Arbor, MI). Two treatments were performed in each animal: a spherical 1.0 × 1.0 × 1.0 cm and ovoid 1.0 × 1.0 × 2.0 cm treatment zones. MRI immediately post-procedure was evaluated for histotripsy treatment zone size and imaging appearance, followed immediately by sacrifice. Tissue was then reviewed for percent cellular destruction and precision.

RESULTS

Treatment zones measured on post treatment MRI were similar to prescribed volumes (spherical = 0.60 (+/- 0.11) cm³, ovoid = 1.23 (+/- 0.40) cm³, p > 0.05 vs. prescribed). MRI demonstrated well demarcated treatment zones and imaging findings consistent with cellular destruction. Histology demonstrated sharp transitions to normal tissue (mean 0.33 (+/- 0.13) cm), and high degrees of cellular destruction (mean 76% (+/- 12.5), range of 50-100%) in the treated tissue. Edema within the overlying muscle was seen in 2/8 treatments.

CONCLUSION

Histotripsy is capable of safely creating precise histotripsy treatments within the superficial neck of a porcine thyroid model without evidence of considerable complications.

Symptomatic aseptic necrosis of benign thyroid lesions after microwave ablation: risk factors and clinical significance

BACKGROUND

Symptomatic aseptic necrosis (SAN) followed by nodule rupture is a kind of severe complications after thermal ablation for benign thyroid nodules (BTN). No studies are available to evaluate its pathologic process, clinical manifestations, risk factors and effectiveness of therapies after microwave ablation (MWA).

METHODS

From 2012 to 2019, 398 patients who received MWA for BTN were retrospectively reviewed. Clinical data included baseline patient characteristics, imaging features (internal vascularity and the proportion of the solid component), ablation power and time, complications and prognosis were collected and documented.

RESULTS

Ten patients (2.51%) experienced post-MWA SAN, eight patients with nodule rupture and the other two without. The mean time from MWA to SAN symptom was 8.6 days and to rupture was 16.3 days. The initial symptoms of SAN patients were neck bulging, swelling and discomfort. Patients would go through nodule rupture once the nodule contents extended into the extrathyroidal area with the discontinuity of the anterior thyroid capsule, and fistula formed unavoidably in this condition. Incision drainage was effective for rupture and early treatment of non-steroidal anti-inflammatory drug might cure the early-stage SAN. Multivariate analysis showed sex (OR = 0.13; 95% CI: 0.03, 0.61; p=.03) was the risk factor leading to SAN and males were more vulnerable to SAN.

CONCLUSION

SAN after MWA came earlier and initially illustrated as neck bulging, swelling and discomfort. Early detection and early treatment might prevent the rupture of nodules. Once the breakdown of thyroid capsule occurred, rupture of ablated nodules out of skin was unavoidable and invasive procedures might be the most effective treatment.

Comparison of radiofrequency ablation and microwave ablation for benign thyroid nodules: A systematic review and meta-analysis

PURPOSE

To compare the effectiveness and safety of radiofrequency ablation (RFA) and microwave ablation (MWA) for the treatment of benign thyroid nodules (BTNs).

METHODS

PubMed, Embase and Cochrane databases were searched up to September 11, 2020. Volume reduction rate (VRR), symptomatic and cosmetic scores analysed by standardized mean difference (SMD), and complications analysed by risk difference (RD) were performed to evaluate the efficacy and safety of RFA and MWA for treating BTNs.

RESULTS

Five eligible studies were included. 899 patients with 956 BTNs and 869 patients with 938 BTNs received RFA and MWA, respectively. RFA and MWA have the similar pooled 3-month (56.0% vs. 53.9%, p = .668) and 6-month (80.8% vs. 74.9%, p = .080) VRRs. But RFA showed a significantly higher VRR than MWA after 12 months (86.2% vs. 80.0%, p = .036). The pooled symptomatic and cosmetic scores decreased significantly after 6 and 12 months in both RFA and MWA. The improvements of symptoms were equivalent between two groups at 6 (SMD: 1.17 vs. 1.12, p = .930) and 12 (SMD: 1.46 vs. 1.45, p = .930) months. No significant differences in cosmetic scores were found between two groups at 6 (SMD: 0.87 vs. 0.94, p = 0. 334) and 12 (SMD: 1.21 vs. 1.15, p = 0. 872) months. Major (RD = -0.02, P = .107) and minor (RD = 0.00, p = .661) complications did not significantly differ between RFA and MWA.

CONCLUSIONS

RFA and MWA are effective and safe treatment modalities for BTNs. But RFA showed a superior 12-month VRR. RFA may have a better long-term effect on volume reduction of nodules compared with MWA.

High-intensity focused ultrasound (HIFU) therapy for benign thyroid nodules: a 3-year retrospective multicenter follow-up study

BACKGROUND

Outcomes of high-intensity focused ultrasound (HIFU), as a non-surgical treatment option for benign symptomatic thyroid nodules, has mainly been based on single-center studies and short-term follow-up. Therefore, we assessed the safety, and long-term efficacy of HIFU in benign thyroid nodules among four centers with expertise in thyroid mini-invasive procedures.

PATIENTS AND METHODS

Retrospective three year follow-up study in four European centers, treating solid benign thyroid nodules causing pressure symptoms and/or cosmetic concerns. Nodule volume reduction was assessed at 1, 3, 6, 12, 24, and 36 months post-treatment. Technical efficacy, defined as a volume reduction rate (VVR) >50% was evaluated at 6, 12, 24 and 36 months. Predictive factors of efficacy were assessed using logistic models. Complications and side effects were classified according to the Interventional Radiology Guidelines and changes in local symptoms were scored on a visual-analog scale.

RESULTS

Sixty-five patients (mean age 51.1 ± 14.0 years; 86.2% women) with a single thyroid nodule and a mean baseline nodule volume of 9.8 ± 10.3 mL were treated with a mean energy of 7.1 ± 3.1 kJ (range: 2.0 to 15.5 kJ). Median nodule volume reduction was 31.5% (IQR: -38.6% to -23.1%) at 12 months and 31.9% (IQR: -36.4% to -16.1%) at 36 months. Technical efficacy was obtained in 17.2% of cases at 6 months, 17.8% at 12 months, 3.4% at 24 months, and 7.4% at 36 months. The number of treated pixels and the mean energy delivered were positively correlated to VRR at 1, 6 and 12 months. The risk of treatment failure decreased by 4.3% for each additional unit of energy delivered. The procedure duration was inversely correlated with treatment failure (OR 1.043, 95% CI: 1.011-1.083; p = 0.014). Improvement of cervical pressure symptoms or cosmetic complaints were observed in less than 15% of the cases at 12, 24 and 36 months. Horner's syndrome occurred in one case (1.5%) and minor complications, not requiring treatment, in three (4.6%) patients. No change in thyroid function was registered.

CONCLUSIONS

HIFU carried a low risk of complications. A single treatment resulted in a 30-35% thyroid nodule volume decrease within one year, reduction that remained stable for 2 years. Outcomes varied significantly between centers with different HIFU expertise. Focus on improved HIFU technology, adequate training, and appropriate selection of patients is needed to achieve efficacy comparable to other thermal ablation procedures.

Radiofrequency ablation and thyroid nodules: updated systematic review

PURPOSE

In the thyroid gland, radiofrequency ablation (RFA) is being applied to both benign nodules and cancers internationally, while interest is also growing in the West. Benign thyroid nodules (BTNs) may be candidates for intervention when symptoms develop. For differentiated thyroid cancers (DTC), surgery is currently the first-line treatment. However, for candidates with high surgical risk or those who refuse to undergo repeated surgery, newer techniques such as RFA are an option. Surgery is associated with complications including hypothyroidism, voice change, hypocalcemia, and a scar. RFA has been used in Asian and European institutions as an alternative to surgery, but is relatively new in North America. Although RFA is not associated with significant complications, few randomized control trials have assessed its efficacy. The studies to date suggest a low rate of severe complications and a small need for thyroid hormone replacement following RFA. Further large-scale studies focusing on a Western population are needed. The aim of this review is to evaluate the evidence with respect to the current studies and data about the safety and efficacy of radiofrequency ablation for the management of BTNs and DTC.

METHODS

We systematically searched the PubMed/MEDLINE, EMBASE, Clinical Queries, and Web of Science databases, for articles published up to April 30th, 2020.

RESULTS

Total of 75 studies that met the inclusion criteria were included in the review. Thirty-five studies focused on RFA use for solid nodules, 12 studies on predominantly cystic nodules, 10 for autonomously functioning thyroid nodules, and 18 studied were published on differentiated thyroid cancer.

CONCLUSIONS

RFA seems to be an effective and safe alternative to surgery in high-risk surgical patients with thyroid cancers and for selected BTNs. Additional trials with longer follow-up in North American patients are needed to validate its full role in the armamentarium of thyroid ologists.

Safety and Efficacy of Physical Thermal Ablation Combined Sorafenib for Hepatocellular Carcinoma: A Meta-analysis

BACKGROUND AND AIMS

To compare the efficacy and safety of physical thermal ablation (PTA), including radiofrequency ablation (RFA) and microwave ablation (MWA), combined with sorafenib and physical thermal ablation alone for the control and treatment of hepatocellular carcinoma (HCC) according to the available literature.

METHODS

Comprehensive searches were performed on PubMed, Embase, CNKI, the Cochrane Library, China Biomedical Literature Database (known as CBM), Weipu Journal, and Wanfang Database. Meta-analysis was performed using Revman 5.3 software.

RESULTS

A total of 15 studies, consisting of 2,227 HCC patients, were selected and included in this meta-analysis. Compared with the RFA-alone group, the patients in the RFA+sorafenib group had longer 1-, 2-, and 3-year overall survival (all p<0.05), better overall efficacy (p<0.0001), longer radiofrequency interval (p<0.001), and lower 2-year recurrence rate (p=0.02). The 1-year overall survival (p=0.003) and overall efficacy (p=0.002) of the MWA+sorafenib group were also higher than those of the MWA-alone group. The incidences of adverse reactions in the RFA+sorafenib group, such as hand-foot skin reactions (p<0.001), diarrhea and constipation (p=0.0001), hypertension (p=0.009), and alopecia (p<0.001), were significantly higher than those in the RFA-alone group.

CONCLUSIONS

RFA or MWA combined with sorafenib has produced a better therapeutic effect on HCC than physical thermal ablation alone; however, adverse reactions have been obvious. It is necessary to evaluate the safety of combination therapy, and pay close attention to the adverse reactions that develop in patients.

[Ultrasound-guided minimally invasive diagnostics and treatment in the head and neck area]

Tumoral lesions in the head and neck region represent a diagnostic and therapeutic challenge in otorhinolaryngologic routine. High-resolution ultrasound is usually able to guide diagnosis. Nevertheless, a definite differentiation between benign and malignant lesions can only be achieved by tissue biopsy. The various options for obtaining samples for histopathological or cytological examination-from minimally invasive ultrasound-guided fine-needle biopsy to punch biopsy and open surgical biopsy-will be discussed in the first part along with the associated advantages and disadvantages. In the second part of this CME article, minimally invasive ultrasound-guided therapeutic options in the head and neck region which can be performed on an outpatient basis are depicted.

RFA and benign thyroid nodules: Review of the current literature

Benign thyroid nodules (BTNs) are commonly found in the general population. They are usually asymptomatic and their incidence has increased as a result of wide-spread use of ultrasound. Benign nodules are typically monitored clinically until they increase in size, resulting in compressive symptoms warranting surgery. However, although surgery is generally well-tolerated and of low-risk, it is associated with a small risk for several complications including hypothyroidism, nerve injury, hematoma, injury to other structures and wound infection. Recently, newer image-guided ablation techniques including radiofrequency ablation (RFA) have been introduced. RFA has a similar safety profile when compared to surgery and has shown promising results in challenging surgical candidates. Though several studies have been published in Asian and European countries on the efficacy of RFA, limited data is available on the North American population. The aim of the study is to review the current literature establishing the clinical outcomes and safety of RFA for benign nodules.

LEVEL OF EVIDENCE

V.

Comparative efficacy of different ultrasound-guided ablation for the treatment of benign thyroid nodules: Systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Percutaneous ablation is currently deemed an additionally treatment option for benign thyroid nodules in the world, but possibly different effect among the ablation modalities is not clear. So we aim to evaluate the efficacy and complications of thermal/chemical ablation by network meta-analysis.

MATERIALS AND METHODS

In the network meta-analysis, PubMed, EMBASE and the Cochrane Library databases were searched from 1980 to 2020. Studies of adults with thyroid benign nodules under percutaneous ablation therapy were included. Percentage mean volume change, symptom score change, cosmetic score change and complications were evaluated by network meta-analysis.

RESULTS

In the network meta-analysis, Radiofrequency Ablation(RFA) with 2 treatment sessions group was associated with the highest reduction for the mean volume change during 6-month follow-up (MD = 79.09 and 95% CrI:48.23-89.94). There is no significant difference in the incidence of complications. Subgroup analysis showed that 2 sessions of Radiofrequency Ablation (RFA) ranks the highest probability (surface under the cumulative ranking curve (SUCRA) values 77.9) of being the most efficacious treatment for solid or predominantly solid benign nodules. Ethanol ablation (EA) ranked first (SUCRA value 81.1) in the treatment for cyst or predominantly cyst benign nodules.

CONCLUSION

RFA appears to be superior to other US-guided percutaneous ablation in reducing benign thyroid nodule volume during short- and long-term follow-up. In the subgroup analysis, RFA with 2 treatment sessions showed the most significant effectiveness for solid benign thyroid nodules and EA showed more effectiveness to decrease the volume of cyst benign thyroid nodules.

Ablating Aspiration Needle Tract Prior to Microwave Ablation Can Improve Therapeutic Outcomes for Predominantly Cystic Thyroid Nodules

PURPOSE

To investigate whether ablating the aspiration needle tract could improve the safety and efficacy of ultrasound-guided microwave ablation (MWA) for predominantly cystic thyroid nodules.

MATERIALS AND METHODS

This retrospective study evaluated 41 predominantly cystic thyroid nodules that underwent MWA between June 2017 and August 2019. The nodules were stratified by different procedures into two groups: the aspiration needle tract was ablated before cyst fluid aspiration and MWA when treating 26 nodules in Group A, while the other 15 nodules in Group B underwent MWA directly after cyst fluid aspiration. Baseline characteristics, intervention time, hospital stays, nodules with intraoperative intracystic hemorrhage, and postoperative complications were compared between the two groups. Volume, volume reduction rate (VRR), compressive score (CS), and aesthetic score (AS) were evaluated during follow-up.

RESULTS

Both groups achieved decreases in volume, CS, and AS, as well as an increase in VRR. The volumes and VRRs in Group A at 1, 3, 6, and 12 months were significantly smaller and greater than those in Group B (p < 0.001). The incidence of intraoperative intracystic hemorrhage in Group A was significantly lower than that in Group B (p=0.035). Compared to Group B, hospital stays were much shorter in Group A (p=0.040). There were no significant differences in intervention time, cystic fluid volume or postoperative complications.

CONCLUSION

Aspiration needle tract ablation dramatically reduces the incidence of intraoperative intracystic hemorrhage and markedly improves the efficacy of MWA for predominantly cystic thyroid nodules.

A Propensity Score Matching Study Between Microwave Ablation and Radiofrequency Ablation in Terms of Safety and Efficacy for Benign Thyroid Nodules Treatment

BACKGROUND

Large benign thyroid nodules often lead to cosmetic problems and compression on trachea. Thermal ablation is an effective method for benign thyroid nodules treatment. Among all the thermal ablation techniques, microwave and radiofrequency are frequently used energy sources. However, treatment outcomes of the two ablation types have not been compared in detail. Therefore, we conducted this study aiming for comparing the safety and efficacy of the two ablation techniques in benign thyroid nodules treatment.

METHODS

Information was retrospectively collected from patients with benign thyroid nodules, who received radiofrequency ablation or microwave ablation between January 1, 2018, and December 31, 2019, in a main hospital in South China. Patients were divided into microwave ablation group and radiofrequency ablation group according to the techniques applied. A propensity score matching was performed to balance the baseline indexes between the two groups. We also recorded and analyzed the operative variables including operative duration, intraoperative blood loss, hospitalization time, and overall costs. Postoperative quality of life, volume reduction rates, and complication rates were routinely evaluated during the follow-up by asking patients to fulfil questionnaires at the 1^st, 3^rd, 6^th, 12^th, and 18^th postoperative month.

RESULTS

A total of 943 patients receiving microwave ablation or radiofrequency ablation in the years of 2018 and 2019 met our inclusion criteria. After 1:1 propensity score matching, 289 pairs of patients were matched. There was no significant difference between the two groups in operative duration, intraoperative blood loss, hospitalization time, overall cost, quality of life scores, complication rates or volume reduction rates.

CONCLUSION

There was no significant difference between microwave and radiofrequency ablation in terms of safety and efficacy. Both of the two techniques` are ideal therapeutic methods in benign thyroid nodules treatment.

REGISTRATION NUMBER

ChiCTR2000034764.

Microwave Ablation of Visible Benign Thyroid Nodules with Different Internal Characteristics: A Comparative Study with Follow-up Results

PURPOSE

To investigate the effects of microwave ablation (MWA) on visible benign thyroid nodules (BTN) with different internal characteristics.

MATERIALS & METHODS

A total of 51 cases with 53 visible BTN were treated by ultrasound-guided percutaneous MWA. The 53 nodules were classified into three categories according to the internal characteristics, which were simple solid, mainly solid and mainly cystic nodules. Ultrasound examinations were performed to evaluate the volume shrinkage rations during follow-up. The thyroid functions and the cervical cosmetic scores were evaluated. The complications were observed during and after ablation.

RESULTS

A total of 53 symptomatic BTN were treated by MWA completely. The average volume of the nodules was 11.68 ± 10.16 ml, the volume reduction rates (VRR) at 1st, 3rd, 6th, 12th, and 18th months after ablation were 0.29 ± 0.27, 0.46 ± 0.25, 0.67 ± 0.19, 0.83 ± 0.10, and 0.92 ± 0.10, respectively. The VRR was significantly different among the three categories of lesions (p < 0.05). The symptoms of all patients were improved. Thyroid function indicators were fluctuated in normal range. There were no serious complications during and after the procedure.

CONCLUSION

MWA of visible BTN is safe and effective, and the short-time ablation effect is significantly different due to the internal characteristics of the nodule.

Efficacy and safety of high-intensity focused ultrasound (HIFU) for treating benign thyroid nodules: a systematic review and meta-analysis

BACKGROUND

High-intensity focused ultrasound (HIFU) is an emerging thermal ablation technique that has been successfully applied to various benign thyroid nodules.

PURPOSE

To evaluate the efficacy and safety of HIFU for the treatment of benign thyroid nodules.

MATERIAL AND METHODS

The Ovid-MEDLINE and EMBASE databases were searched up to 9 July 2018 for studies describing the use of HIFU to treat benign thyroid nodules. We included studies that have outcomes with sufficient detail to evaluate the volume reduction rate (VRR). The pooled proportions of VRR ≥50% and pooled VRR at one, three, and six months after HIFU were assessed using random-effects modeling. Heterogeneity among studies was determined using Chi-square statistics for pooled estimates and the inconsistency index I².

RESULTS

Seven studies were included in the systematic review and four in the meta-analysis. The pooled VRR at one, three, and six months after HIFU were 17.59 (95% confidence interval [CI] 12.56-22.62), 48.93 (95% CI 42.20-55.66), and 60.43 (95% CI 51.88-68.98). The pooled proportions of VRR ≥50% at six months after HIFU were 75% (95% CI 53-89; I²=73.6%). There were no major complications of HIFU.

CONCLUSION

HIFU may be a safe and effective treatment modality for benign thyroid nodules, especially for small nodules.

Comparison of ultrasound-guided thermal ablation and conventional thyroidectomy for benign thyroid nodules: a systematic review and meta-analysis

Objective: To compare the safety and efficacy of ultrasound-guided thermal ablation and conventional thyroidectomy for benign thyroid nodules (TNs) by performing a systematic review and meta-analysis.Methods: We searched PubMed, Embase, Web of Science and Cochrane Library databases for clinical trials from the date of their inception to 1 April 2019. Two investigators independently examined the trials to select qualified studies, extracted relevant information and assessed the risk of bias according to the Cochrane Collaboration checklist (Oxford, UK). The primary study outcomes were safety (hoarseness, hypothyroidism and postoperative pain) and efficacy (symptom improvement, postoperative cosmetic effects and hospitalization time). This study is registered with PROSPERO (CRD42019125643).Results: Seven studies involving 1289 patients were included. The results demonstrated that the incidences of hoarseness [odds ratio (OR) 0.33, 95% confidence interval (95% CI) (0.14, 0.79)], hypothyroidism [risk difference (RD) -0.31, 95% CI (-0.34, -0.28)] and postoperative pain [OR 0.35, 95% CI (0.25, 0.49)] were lower, and the hospitalization time was shorter [standard mean difference (SMD) -4.01, 95% CI (-4.22, -3.81)], in the thermal ablation group than in the conventional thyroidectomy group, and postoperative cosmetic effects were better [relative risk (RR) ratio 1.12, 95% CI (1.01, 1.24)] (p < 0.05). For symptom improvement, the difference was not statistically significant.Conclusions: This study shows that for benign TNs, ultrasound-guided thermal ablation may have potential advantages in terms of safety, cosmetic effects and shorter hospitalization time compared with conventional thyroidectomy, while symptom improvement is the same.

Thermal Ablation of Benign Thyroid Nodules and Papillary Thyroid Microcarcinoma

Due to the increasing rates of physical examination and application of advanced ultrasound machines, incidences of benign thyroid nodules (BTNs) and papillary thyroid microcarcinoma (PTMC) were dramatically up-regulated in recent years. Thermal ablation (TA) has been widely used and regarded as a safe and effective method to eliminate or reduce BTNs and recurrent low-risk PTMC. However, conclusions using TA to treat primary PTMC are controversial. Recently, several long-term and prospective studies on TA treatment of BTNs and primary PTMC have been reported. Here, we review current literatures and progress on TA treatment of BTNs and PTMC and underline the way to get the best treatment outcomes, providing a comprehensive insight into the research progresses in this field.

Combining high-intensity focused ultrasound (HIFU) ablation with percutaneous ethanol injection (PEI) in the treatment of benign thyroid nodules

OBJECTIVE

Assessing the 6-month efficacy of combined high-intensity focused ultrasound (HIFU) ablation with percutaneous ethanol injection (PEI) in benign thyroid nodules by comparing it with HIFU ablation alone.

METHODS

One hundred and eighty-one (55.2%) patients underwent HIFU alone (group I) while 147 (44.8%) underwent concomitant HIFU and PEI treatment for solid or predominantly solid nodules (group II). Intravenous sedation and analgesia were given before the start of treatment. Extent of nodule shrinkage (by volume reduction ratio (VRR)), pain scores (by 0-10 visual analogue scale) during and after ablation, and rate of vocal cord palsy (VCP), skin burn, and nausea/vomiting were compared between the two groups.

RESULTS

The mean amount of ethanol injected in group II was 1.3 ± 0.7 ml. The 3- and 6-month VRR were significantly greater in group II (60.41 ± 20.49% vs. 50.13 ± 21.06%, p = 0.001; and 71.08 ± 21.25% vs. 61.37 ± 22.76%, p = 0.001, respectively), and "on-beam" treatment time was significantly shorter in group II (26.55 min vs. 30.26 min, p = 0.001). Group II patients reported significantly lower pain score during treatment (2.24 ± 3.07 vs. 4.97 ± 3.21, p < 0.001) and 2 h after treatment (2.23 ± 2.50 vs. 2.97 ± 4.39, p = 0.044). Rates of VCP, skin burn, and nausea or vomiting were not significantly different (p > 0.05).

CONCLUSIONS

The combined HIFU and PEI approach with improved administration of intravenous sedation and analgesia was associated with a significantly better 6-month efficacy than HIFU alone in benign thyroid nodules without compromising the safety and comfort of patients.

KEY POINTS

• Concomitant HIFU and PEI have a better treatment efficacy than HIFU alone. • Concomitant HIFU and PEI have a comparable safety profile as HIFU alone.

Long-term outcomes of radiofrequency ablation for unifocal low-risk papillary thyroid microcarcinoma: a large cohort study of 414 patients

OBJECTIVES

The purpose of this study was to evaluate the long-term efficacy and safety of radiofrequency ablation (RFA) for low-risk papillary thyroid microcarcinoma (PTMC) in a large population.

METHODS

From June 2014 to December 2017, 414 patients (323 females, 91 males, mean age 43.56 ± 9.79 years, range 18-73 years) with unifocal low-risk PTMC confirmed by core-needle biopsy (CNB) were treated by RFA. Patients were followed up at 1, 3, 6, and 12 months and every 6-12 months thereafter by ultrasound and contrast-enhanced ultrasound (CEUS). The volume and the volume reduction ratio (VRR) were calculated. Recurrence and lymph node or distant metastasis were evaluated.

RESULTS

The mean initial volume was 92.74 ± 83.43 mm³ (range 4.19-490.07 mm³), which decreased significantly to 1.37 ± 7.94 mm³ (range 0-67.97 mm³) at a mean follow-up time of 42.15 ± 11.88 months (range 24-69 months) with a mean VRR of 98.81 ± 6.41% (range 50-100%). No life-threatening or delayed complications occurred. After RFA, 366 tumors (88.41%) completely disappeared. The overall incidence of local tumor progression rate was 3.62%. Among them, one patient (0.24%) was diagnosed to have residual cancer by CNB and underwent additional RFA. Four patients (0.97%) developed metastatic lymph node, and 10 patients (2.42%) had recurrent PTMC. A total of 13 patients underwent additional RFA, and 11 lesions completely disappeared during the follow-up.

CONCLUSIONS

RFA is an effective and safety treatment for low-risk PTMC after a long-term follow-up period for a large cohort with careful patient enrollment evaluation.

KEY POINTS

• Radiofrequency ablation is an effective and safe alternative for low-risk PTMC. • The overall incidence of local tumor progression rate was low. • No life-threatening or delayed complications occurred.

Single-session high-intensity focused ultrasound (HIFU) ablation for benign thyroid nodules: a systematic review

BACKGROUND

Thyroid nodules are common; the majority of them are benign and asymptomatic. Thyroidectomy might be an option; however, the frequency of post-operative complications mandates the development of alternative approaches, such as high-intensity focused ultrasound ablation (HIFU). HIFU induces thermal destruction without penetrating the skin. The present systematic review aims to synthesize all available data, evaluating studies with single-session HIFU therapy and investigating its efficacy.

MATERIALS AND METHODS

This systematic review was conducted in accordance with the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and MetaAnalyses). Eligible articles were identified by a search of Medline bibliographic database (PubMed) and Cochrane Library. Out of 39 results, 11 articles were considered to meet the inclusion criteria.

RESULTS

All eligible studies included patients with solid or predominantly solid benign thyroid nodules. All patients were treated with the same HIFU device. The success rate of the method was defined in the majority, with the volume reduction rate (VRR) over 50% from baseline. The mean or median VRR ranged from 48.7 to 70.41%, depending on the last follow-up date. No major complications were observed.

CONCLUSION

Single-session HIFU is safe and effective for the treatment of benign thyroid nodules.

2020 European Thyroid Association Clinical Practice Guideline for the Use of Image-Guided Ablation in Benign Thyroid Nodules

Standard therapeutic approaches for benign thyroid lesions that warrant intervention are surgery for cold and either surgery or radioiodine for autonomously functioning thyroid nodules (AFTN). Image-guided thermal ablation (TA) procedures are increasingly proposed as therapy options for selected clinical conditions. Due to mounting scientific evidence and widening availability, ETA considered it appropriate to develop guidelines for the use of TA in adult patients. TA procedures are well tolerated, but a dedicated training of the operators is required and information on possible complications needs to be shared with the patients. The following factors should be considered when weighing between observation, surgery, and TA for benign thyroid nodules. In solid non-hyperfunctioning nodules, TA induces a decrease in thyroid nodule volume, paralleled by improvement in symptoms. Nodule re-growth is possible over time and may necessitate repeat treatment, or surgery, in a dialogue with the patient. In AFTN, radioactive iodine is the first-line treatment, but TA may be considered in young patients with small AFTN due to higher probability of restoring normal thyroid function and avoidance of irradiation. In cystic nodules, ethanol ablation (EA) is the most effective and least expensive treatment. TA may be considered for cystic lesions that relapse after EA or have a significant residual solid component following drainage and EA. TA should be restricted to benign lesions that cause symptoms or cosmetic concern. Presently, laser and radiofrequency ablation are the most thoroughly assessed techniques, with similar satisfactory clinical results. Microwaves and high-intensity focused ultrasound therapy options remain to be fully evaluated.

N-acetylcysteine alleviates liver injury by suppressing macrophage-mediated inflammatory response post microwave ablation

OBJECT

To investigate N-acetyl-cysteine (NAC) would able to alleviate liver injury and systemic inflammatory response caused by microwave ablation (MWA) in rats.

MATERIALS AND METHODS

Male Sprague-Dawley rats weighing 150-200 g were randomly divided into sham group (only anesthesia and laparotomy except MWA but with intraperitoneal PBS or NAC solution injection according to different situations), control group (intraperitoneal PBS injection for comparation 2 h prior to MWA), and NAC-treated group (intraperitoneal N-acetyl-cysteine (300 mg/kg) injection 2 h prior to MWA). Experimental rats were sacrificed at 4 h following operation in line with the liver injury severity curve. Liver tissue and serum samples were collected for determination of pathology, apoptosis, macrophages contents and protein expression.

RESULTS

The elevated serum level of liver enzymes, Myeloperoxidase (MPO) and inflammatory factors (TNF-α and CXCL1) in MWA-treated rats revealed injurious and pro- inflammatory effect of MVA. Macrophages aggregation was detected in MWA exposure rats similarly. and NAC pre-conditioning mitigate liver damage and hepatocyte apoptosis, besides macrophages accumulation and following inflammatory response in liver tissue.

CONCLUSION

Our results demonstrated that N-acetyl-cysteine application alleviate macrophages aggregation and inflammatory response in liver suffering microwave ablation, and mitigating liver injury and cell apoptosis.

Efficacy and Safety of Thermal Ablation Techniques for the Treatment of Primary Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-Analysis

Background: The increased incidence of primary papillary thyroid microcarcinoma (PTMC) has led to increased research in the field of nonsurgical therapeutic options for those who refuse surgery or are at high risk for surgery. The study aimed at comprehensively evaluating the efficacy and safety of thermal ablation techniques for the treatment of PTMC via a systematic review and meta-analysis. Methods: The Pubmed MEDLINE and EMBASE databases were searched for studies reporting the efficacy and safety of thermal ablations (radiofrequency-, laser-, and microwave-ablations [RFA, LA, and MWA]) until August 10, 2019. A review of 105 potential papers identified 11 eligible papers, including 715 patients. The pooled proportions of complete disappearance and recurrence, and the pooled estimates of mean volume reduction and its rate of the treated PTMC were assessed by using random-effects modeling. The pooled proportions of overall and major complications were calculated. Subgroup analysis was performed according to the treatment modality. Between-study heterogeneity was explored by using χ² statistic for pooled estimates and inconsistency index I². Quality of the studies was evaluated by using the Risk of Bias Assessment Tool for Nonrandomized Studies. Results: The pooled proportions of complete disappearance and recurrence of PTMC were 57.6% [95% confidence interval (CI): 35.4-79.8] and 0.4% [95% CI: 0-1.1], respectively. The pooled estimates of mean volume reduction and its rate were 73.5 mm³ [52.4-94.6 mm³] and 98.1% [95% CI: 96.7-99.5], respectively. The pooled proportions of overall and major complications were 3.2% [95% CI: 1.1-5.2] and 0.7% [95% CI: 0-1.5], respectively. Significant between-study heterogeneity was observed for complete disappearance (p < 0.001, I²: 99%), mean volume reduction (p < 0.001, I²: 93%), and its rate (p < 0.001, I²: 86%). Subgroup analysis revealed heterogeneity of the complete disappearance proportion among the treatment modality (I² range: 95-100%). RFA showed the highest mean volume reduction rate (99.3%), followed by MWA (95.3%) and LA (88.6%) (p < 0.001). Conclusions: All thermal ablation techniques were effective and safe for the treatment of PTMC. However, each treatment modality had significant heterogeneity with respect to complete disappearance of PTMC. Compared with RFA and MWA, LA was less effective in reducing the volume of PTMC.

Identifying predictive factors for efficacy in high intensity focused ultrasound (HIFU) ablation of benign thyroid nodules - a retrospective analysis

Objective: Since it is unclear whether clinical parameters can independently predict the subsequent treatment response following high intensity focused ultrasound (HIFU) ablation of benign thyroid nodules, we aimed to examine clinical factors that may independently predict 12-month efficacy after HIFU treatment.Methods: One hundred and forty patients who had single ablation were categorized into two groups, those with 12-month nodule shrinkage above the median (Group I, n = 70) and with shrinkage below or equal to the median (Group II, n = 70). Baseline characteristics, treatment parameters, percentage change in serum TSH, Free thyroxine (FT4) and thyroglobulin (Tg) from baseline to Day 4 and appearance of microbubbles (hyperechoic marks (HEMs)) during treatment were compared between groups. To determine independent factors, a multivariate analysis was done by logistic regression analysis.Results: Baseline characteristics and treatment parameters were comparable between groups. However, on Day-4, group I had significantly lower serum TSH (0.49mIU/L vs. 0.84mIU/L, p = 0.011) and higher FT4 (22.11 pmol/L vs. 18.47 pmol/L, p = 0.008) than group II. The percentage change in TSH, FT4 and Tg were significantly greater in group I (p = 0.002, p = 0.009 and p = 0.001 respectively). The proportion of HEMs observed during treatment was also significantly higher in group I (42.69% vs. 31.72%, p = 0.030). Among the significant factors, the percentage change in FT4 was the only independent factor for 12-month shrinkage (OR = 1.018, 95%CI =1.003-1.032, p = 0.017).Conclusions: Percentage change in serum FT4 on post-treatment Day-4 was an independent blood parameter for the subsequent nodule shrinkage at 12 months. This finding could potentially facilitate the decision for earlier retreatment of treated nodules.