Efficacy and Safety of Thermal Ablation for Solitary T1bN0M0 Papillary Thyroid Carcinoma: A Multicenter Study

Comparison of Ultrasound-Guided Percutaneous Microwave Ablation and Conventional Thyroidectomy in the Treatment of Papillary Thyroid Microcarcinoma: Meta-Analysis

Purpose: To perform a meta-analysis of clinical trials comparing percutaneous microwave ablation (PMWA) guided by ultrasound with conventional thyroidectomy for the management of papillary thyroid microcarcinoma (PTMC), analyzing feasibility, safety, and long-term efficacy, and to provide clinical guidance for the treatment selection of PTMC. Methods: Embase, PubMed, Cochrane Library, Web of Science, CNKI, VIP Database, and Wanfang Database were systematically searched to identify clinical studies of PMWA or thyroidectomy for PTMC up to December 2023. The relevant data from the articles were extracted, and the data analysis was performed using RevMan 5.4 software. Results: A total of 442 articles were identified and subsequently screened based on the inclusion and exclusion criteria, 9 clinical studies involving a total of 1577 patients were included, with 788 patients in the PMWA group and 789 patients in the surgery group. Following data extraction and statistical analysis, in comparison to the surgery group, the PMWA group had shorter operation time [mean differences (MD) = -36.36; 95% CI -55.66 to -17.06; P = .0002], shorter hospital stay (MD = -3.93; 95% CI -5.55 to -2.30; P < .00001), less intraoperative bleeding (MD = -21.25; 95% CI -27.36 to -15.15; P < .00001), and lower hospital costs (MD = -1.00; 95% CI -1.33 to -0.66; P < .00001), all with statistical significance. The comparison of postoperative complications revealed a lower incidence of complications in the PMWA group compared to the surgery group [relative risk (RR) = 0.29; 95% CI 0.21 to 0.40; P < .00001], with statistical significance. Thyroid-related hormone analysis showed that the free triiodothyronine (MD = 0.61; 95% CI 0.33 to 0.90; P < .00001) and free thyroxine (MD = 1.81; 95% CI 0.94 to 2.68; P < .0001) levels in the PMWA group were higher than those in the traditional surgery group, while the levels of thyroid-stimulating hormone were lower than those in the traditional surgery group (MD = -7.63; 95% CI -10.25 to -5.01; P < .00001), with statistically significant differences, indicating that PMWA had a smaller impact on thyroid function. In 2 studies, there were no statistically significant disparities in postoperative recurrence or lymph node metastasis (LNM) between the 2 cohorts (RR = 0.70; 95% CI 0.33 to 1.50; P = .36). There were no statistically significant differences in physiological health score between different groups and different time points before and after treatment (P > .05); However, the mental component score and the total score of the Medical Outcomes Study (MOS) item short-form health survey were significantly elevated in the ablation group compared to the excision group post-treatment (P < .05). Conclusion: For patients with low-risk PTMC with definitive diagnosis and precise risk stratification, PMWA can be selected. PMWA treatment for patients with PTMC is comparable to conventional surgical treatment and has the advantages of minimal trauma, rapid recovery, no scarring, and fewer complications, which are superior to open surgery to a certain extent. For patients with ambiguous preoperative diagnosis and uncertainty regarding LNM status, surgical intervention is the optimal choice.

Complications of ultrasound-guided thermal ablation of thyroid nodules and associated risk factors: an experience from 9667 cases

OBJECTIVES

To evaluate the safety of ultrasound-guided thermal ablation (UGTA) for thyroid nodules (TNs) by analysing complications and related risks.

MATERIALS AND METHODS

This retrospective, single-centre study reviewed patients who underwent UGTA (microwave or radiofrequency ablation) between January 2018 and March 2023. The incidence of complications was recorded and assessed during and immediately after ablation,1-3 h later, and at 1 month, 3 months, and 6 months. Univariate and multivariate analyses were performed to identify risk factors for hoarseness and haemorrhagic complications.

RESULTS

We reviewed 9667 cases in this study. Overall, 4494 (46.49%) cases underwent microwave ablation, while 5173 (53.51%) cases underwent radiofrequency ablation. The overall complication rate was 4.43%. The incidence of major complications was 1.94% (haemorrhage, 1.32%; hoarseness, 0.54%; and symptomatic aseptic necrosis, 0.08%). The incidence of minor complications was 2.45%. A large nodule volume, radiofrequency ablation, hyper-enhancing nodules, benign nodules, higher preoperative blood pressure, hyperthyroidism, and higher ablation power were independent risk factors for haemorrhage. Dorsal nodules and a higher ablation power were independent risk factors for hoarseness. All complications were resolved.

CONCLUSION

This study suggests that UGTA is a safe treatment for TNs. Several risk factors for haemorrhage and hoarseness should be considered before performing UGTA. Different ablation modalities should be considered for patients with different conditions.

CLINICAL RELEVANCE STATEMENT

Thermal ablation may be a safe treatment for eligible patients with TNs.

KEY POINTS

We analysed the complications and risk factors associated with UGTA in 9667 cases. The complication rate was 4.43%; 1.94% were major complications. Risk factors of haemorrhage and hoarseness should be considered. UGTA was a safe method for the treatment of TNs.

Incomplete ablation of thyroid cancer: Achilles' Heel?

BACKGROUND

In recent years, the incidence of thyroid nodules has increased significantly. There are various ways to treat thyroid nodules, and ablation therapy is one of the important ways to treat thyroid nodules. However, there are many complications and deficiencies in the current ablation treatment of thyroid nodules, especially the incomplete ablation of thyroid cancer nodules, which limits the further application of ablation technology. In this paper, we report two cases of incomplete ablation of thyroid nodules, one of which underwent surgical treatment due to anxiety after ablation, and the postoperative pathology confirmed that there was still residual papillary thyroid carcinoma, and the other patient underwent an operation after ablation, but visited our medical institution again due to cervical lymph node metastasis in a short period of time, and after radical cervical lymph node dissection, pathology confirmed multiple cervical lymph node metastasis. Radionuclide therapy was performed after surgery, and two patients are currently receiving endocrine suppression therapy, and their condition is stable with no signs of recurrence.

CONCLUSION

The incomplete ablation of thyroid cancer nodules limits the development of ablation therapy, making ablation treatment a double-edged sword. Guidelines and expert consensus can guide their development, but they need to evolve with the times, and a multidisciplinary diagnostic team can help screen the most suitable patients. Only by using this technology more standardly, using the most appropriate technology, and treating the most suitable patients, can benefit more and more patients.

Comparison between thermal ablation and surgery in low risk papillary thyroid carcinoma: a prospective study

Objective

To conduct a comparative analysis of the efficacy, safety, and impact on quality of life outcomes between thermal ablation and surgical interventions in patients diagnosed with papillary thyroid carcinoma (PTC).

Methods

A prospective study was undertaken, enrolling patients with PTC ≤5mm who underwent radiofrequency ablation (RFA), laser ablation (LA), or surgery, for analysis of efficacy and safety outcomes. The Thyroid Cancer-Specific Quality of Life questionnaire was administered to all patients before treatment and at 3, 6, and 12 months post-treatment.

Results

A total of 162 eligible patients were included in the study. Major complications were not observed in the RFA and LA groups, while five cases were reported in the surgery group, although no statistically significant differences were observed. Minor complications were documented in two, three, and 14 patients in the RFA, LA, and surgery groups, respectively, with no significant variances noted. Surgical duration and hospitalization time were notably shorter in the thermal ablation groups. At the final follow-up, complete disappearance of nodules was seen in 71.4% of cases treated with RFA and 71.0% of cases managed with LA, with no significant disparities between the groups. Both RFA and LA exhibited similar effects on quality of life, with thermal ablation techniques showing better functional outcomes in comparison to surgery. Across all groups, adverse effects were most pronounced at the 3-month post-treatment mark but gradually reverted to baseline levels in the thermal ablation group, contrasting with the surgery group.

Conclusions

For PTC ≤5mm, both RFA and LA exhibited similar cancer control outcomes and superior quality of life on par with surgery, while minimizing complications. These findings underscore the promise of RFA and LA as potential standard treatments for small PTCs, subject to further confirmation in future studies.

Thermal ablation for the treatment of malignant thyroid nodules: present and future

As the utilization of high-resolution imaging modalities, such as ultrasound, becomes increasingly prevalent, there has been a swift rise in the detection rates of malignant thyroid nodules (MTC). Surgery remains the cornerstone of standard treatment for these nodules. However, the advent and evolution of thermal ablation (TA) techniques, encompassing radiofrequency ablation, laser ablation, and microwave ablation, have emerged as a novel therapeutic avenue for patients with MTC, particularly for those deemed unsuitable for surgery due to high risks or for those who refuse surgery. Presently, TA has been validated as an efficacious and safe intervention for both benign thyroid nodules and a subset of MTC. An expanding body of research has been dedicated to broadening the applicability of TA, initially from recurrent thyroid cancer and lymph nodes to now encompass isolated papillary thyroid microcarcinomas (PTMC) alongside a comprehensive exploration into the expanded parameters such as size, number, and location of PTMC, and its applicability in other types of thyroid cancer. This review provides a detailed synthesis of the clinical evidence about the use of TA in the management of MTC, as endorsed by current guidelines. It further delves into the ongoing research efforts aimed at extending its indications and discusses the prospective implications and challenges of integrating TA into the clinical management paradigms for MTC.

Radiofrequency ablation for solitary T1N0M0 papillary thyroid carcinoma in the danger triangle area: a preliminary analysis

OBJECTIVES

To evaluate the feasibility, efficacy, and safety of radiofrequency ablation (RFA) for solitary T1N0M0 papillary thyroid carcinoma (PTC) in the danger triangle area.

METHODS

94 participants (mean age 44.45 ± 13.08; 73 females) with solitary T1N0M0 PTC in the danger triangle area who underwent percutaneous RFA at the hospital from January 2018 to April 2020 were retrospectively analyzed. Key ablation procedures included sufficient paratracheal fluid isolation, low-power, and short active tip (5 mm working electrode). Tumor size changes at different time points after RFA, technical success rates, tumor disappearance, disease progression, and complications were recorded and compared.

RESULTS

Contrast-enhanced ultrasonography revealed that complete tumor ablation was performed with a 100% success rate in these patients. Post-ablation, the maximum diameter and volume of the ablation zone increased at the first and third month (p < 0.001), followed by a gradual decrease in size, without significant difference by the 6th month. The tumor disappearance rate was 76.59% (72/94), with higher rates in the T1a group compared to the T1b group (80% [64/80] VS57.1% [8/14], p < 0.001). There were no local recurrences. The incidence of new lesions and LNM was 3.2% (3/94), limited to the T1a subgroup. Further ablation was successfully applied to all new lesions and LMN. Mild voice changes were the only complication, with a rate of 3.2% (3/94), resolved within 4 months after RFA.

CONCLUSIONS

Sufficient paratracheal fluid isolation combined with a low-power, short active tip radiofrequency ablation strategy is a safe and effective method for treating solitary T1N0M0 PTC in the danger triangle area.

Sonographic Evolution and Pathologic Findings of Papillary Thyroid Cancer After Radiofrequency Ablation: A Five-Year Retrospective Cohort Study

Background: The criteria for determining technical efficacy of thermal ablation for papillary thyroid carcinoma (PTC) are not clearly defined. We analyzed the involution process of the ablation zone with clear pathologic results on core-needle biopsy (CNB) to clarify the relationship between sonographic changes and pathologic findings. Methods: This retrospective cohort study included 382 patients with unifocal T1N0M0 PTC who underwent radiofrequency ablation (RFA) between May 2014 and August 2021. Patients with a single ablation zone biopsy (recommended at 3 or 6 months for T1a and 6 or 12 months for T1b) and regular neck ultrasound (US)/contrast-enhanced ultrasound imaging follow-up at 1, 3, 6, and 12 months and every 6-12 months thereafter after RFA were included. Patients also underwent yearly chest computed tomography. CNB was performed in the target lesion ablation zone's central, peripheral, and surrounding thyroid parenchyma to detect the presence of tumor cells. If the thyrotropin (TSH) was >2 mU/L, levothyroxine was prescribed with the intention of keeping the TSH 0.5-2 mU/L. Technical efficacy was defined as tumor disappearance by imaging follow-up together with the pathologically confirmed absence of tumor cells in the ablation zone. Results: During the mean follow-up period of 67.8 ± 18.2 months (22-110 months), the overall incidence of persistent disease and the technical efficacy rate were 3.9% (15/382; 2.9% of T1a, and 12.2% of T1b) and 96.1%, respectively. Tumor size (p = 0.03) and subcapsular location (p = 0.04) were risk factors associated with persistent disease. The technical success rate was 100%. Of the 367 ablation zones with benign CNB results, 336 (91.6%) showed tumor disappearance on US and no re-emergence of imaging-visible tumors during follow-up. Male sex (p = 0.006), age <40 years (p = 0.003), T1a tumor (p < 0.01), and energy per milliliter (p < 0.03) were significantly associated with tumor disappearance. Conclusions: US-guided RFA is an effective treatment for small low-risk PTC. Tumor disappearance on US after RFA may suggest an excellent prognosis and confirm complete ablation of the macroscopic tumor, but this sonographic finding is generally late and requires histological confirmation.

Radiofrequency Ablation of Unifocal Papillary Thyroid Microcarcinoma With BRAF V600E Mutation

CONTEXT

To date there is no study on the feasibility of radiofrequency ablation (RFA) for papillary thyroid microcarcinomas (PTMCs) with BRAF V600E mutation.

OBJECTIVE

This study was designed to evaluate the efficiency, safety, and prognosis of ultrasound (US)-guided percutaneous RFA for unifocal PTMCs with BRAF V600E mutation.

MATERIALS AND METHODS

Sixty patients with 60 unifocal BRAF V600E mutation-positive PTMCs who received US-guided RFA between January 2020 and December 2021 were retrospectively analyzed. The mean maximum PTMC tumor diameter was 5.8 ± 1.7 mm (range, 2.5-10.0 mm). All PTMCs were pathologically confirmed by fine needle aspiration or core needle biopsy, and BRAF V600E mutation was confirmed to be positive by real-time fluorescent quantitative polymerase chain reaction. Contrast-enhanced ultrasound (CEUS) was performed immediately after RFA to evaluate whether PTMCs were extendedly ablated. Ultrasound was performed 1, 3, 6, and 12 months after RFA and every 6 months thereafter to evaluate the changes in the ablation zone, local recurrence, and cervical lymph node metastasis (LNM). The complications were recorded and evaluated.

RESULTS

Extended ablation was achieved in all enrolled patients. The ablation zone sizes increased immediately after RFA compared with those of tumors before treatment. One month later, the ablation zone sizes were smaller than immediately after RFA. At the last follow-up assessment, 42 nodules (70.0%) completely disappeared and the ablation zones of 18 nodules (30.0%) showed fissure-like changes. No local recurrence or cervical LNM was detected. Voice change (1.7%) was the only major complication.

CONCLUSION

RFA is effective and safe in treating unifocal PTMCs with BRAF V600E mutation, especially when surgery is not feasible or refused by patients who are unwilling to continue active surveillance.

Clinical outcomes of radiofrequency ablation for solitary T1aN0M0 versus T1bN0M0 papillary thyroid carcinoma: a propensity-matched cohort study

OBJECTIVE

To conduct a cohort study comparing the treatment outcomes of radiofrequency ablation (RFA) therapy for solitary T1aN0M0 (T1a) versus T1bN0M0 (T1b) papillary thyroid carcinoma (PTC).

METHODS

This retrospective analysis comprised 310 patients with low-risk PTC undergoing RFA classified into T1a (n = 272) and T1b (n = 38) groups according to the tumor size. A comparative analysis between the two groups was conducted for the volume reduction ratio (VRR), volume, local tumor progression (LTP), and recurrence-free survival (RFS) before and after 1:2 propensity score matching (PSM). Cox analysis was conducted to examine the influence of several variables, including T1b, on recurrence following RFA for PTC.

RESULTS

The total VRR was 99.99 ± 0.11% throughout the median follow-up duration of 26 months, and the overall incidence of LTP was 2.58% (8/310). No irrecoverable complications occurred after RFA. The variations between the T1a and T1b groups following PSM were insignificant in terms of volume (p = 0.574), VRR (p = 0.574), complete disappearance rate (p = 0.210), LTP incidence (p = 1.000), and RFS rate (p = 0.610). The correlation between T1b and LTP continued to be insignificant (p = 0.686). No distant metastasis or delayed surgery occurred.

CONCLUSIONS

The presence of T1b did not influence the patients' prognoses following RFA for T1N0M0 PTC. After appropriate patient selection and adequate preoperative assessment, RFA has the potential to serve as an effective therapy for individuals with T1a and T1b PTC.

Publications on ultrasound-guided thermal ablation for thyroid nodules from 2000 to 2022: a bibliometric analysis

BACKGROUND

Thyroid nodules are increasingly treated with minimally invasive surgery. Thermal ablation could efficiently treat patients with benign thyroid nodules, recurrent thyroid cancer, and low-risk papillary thyroid carcinoma. This research aims to explore the research field of thermal ablation for thyroid nodules using bibliometric analysis.

METHODS

The web of science core collection (WoSCC) database was utilized from its inception to 1 October 2022, to collect research articles and reviews on ultrasound-guided thermal ablation for thyroid nodules. We applied the R package 'bibliometrix' to summarize the main findings, calculate the occurrences of the top keywords and visualize the international collaboration networks. The co-authorship and co-occurrence analyses were conducted with VOSviewer software. CiteSpace was used to identify the top references and keywords with the highest citation bursts.

RESULTS

A total of 820 publications from 32 countries were retrieved. The annual number of related publications showed an increasing trend. China, Italy, and Korea were the most contributing countries. The University of Ulsan College of Medicine in Korea was the most productive institution, and Jung Hwan Baek published the maximum number of articles. The International Journal of Hyperthermia was the most productive journal. 'Papillary thyroid micro-carcinoma (PTMC)' and 'association guideline' were the most frequently used keywords in the field of thermal ablation for thyroid nodules, which indicated the potential hot research topics and frontiers in the future.

CONCLUSION

This bibliometric study conducts a comprehensive analysis of publications on thermal ablation for thyroid nodules, which aids investigators in discovering potential research directions.

Can pre-operative ultrasound elastography predict aggressive features of solitary papillary thyroid carcinoma?

OBJECTIVE

To investigate whether pre-operative ultrasound elastography (USE) can be used to predict aggressive features of solitary papillary thyroid carcinomas (PTCs).

METHODS

Clinical and USE indices were retrospectively analyzed in 487 patients with surgically confirmed solitary PTCs. The patients were grouped per aggressive features on pathologic testing. Univariate and binary logistic regression analyses were performed to explore independent risk factors of aggressive features.

RESULTS

Univariate analysis revealed standard deviation (SD) values of the tumor shear-wave velocity (SWV) were associated with capsular invasion (p < 0.05). Further, shear-wave elasticity and SWV ratios correlated with extrathyroidal extension (all p < 0.05). The tumor shear-wave elasticity and SWV SD values were associated with cervical lymph node metastasis (CLNM) (all p < 0.05). Binary logistic regression analysis identified location and capsule contact as independent predictive risk factors for capsular invasion (all p < 0.05); size for extrathyroidal extension (all p < 0.05); and sex, age, margin, and suspected CLNM for CLNM (all p < 0.05). However, pre-operational USE indexes were not independent predictors of aggressive features (all p > 0.05).

CONCLUSION

Pre-operative USE indices were not independent risk factors of aggressive features of solitary PTCs. Thus, USE may have a limited value for predicting the aggressive features of PTC.

ADVANCES IN KNOWLEDGE

Pre-operative USE indices may have a limited value for predicting the aggressive features of PTC.

Microwave ablation of solitary T1N0M0 papillary thyroid carcinoma: A case report

BACKGROUND

The gold standard treatment for papillary thyroid carcinoma is total thyroidectomy and indications for microwave thermal ablation for primary thyroid cancers have not yet been clearly established However, some patients refuse surgery and others have no indication for it, for example patients under palliative care as in this case, or cannot undergo surgery, based on their comorbidities. These indications are described in the most recent Korean, North American and European guidelines. Laser ablation, radiofrequency ablation, and microwave ablation are similarly safe and effective, so the choice should be based on the specific competences and resources of the pertaining centers. These indications are Percutaneous minimally-invasive techniques; they can be useful to stop disease progression and as an alternative to surgery in patients with contraindication or who refuse surgery. We present a case of a thyroid papillary carcinoma with 17 mm effectively treated with microwave thermal ablation and without recurrence after one year of follow up.

CASE SUMMARY

The authors present a case of a 71-years-old patient with a left lobe papillary thyroid carcinoma with 13 mm × 17 mm × 13 mm, with no indication for thyroid surgery given the context of another cancer in palliative treatment. Microwave thermoablation was performed on December 2021. Four months later he repeated computed tomography (CT) scan, which showed that the tumor had disappeared. Six months after ablation he underwent a positron emission tomography/CT-fluorodeoxyglucose scan, which didn't show any evidence of hypermetabolic tumor lesions.

CONCLUSION

This case shows microwave thermoablation can be a safe and effective alternative to surgery in patients with no conditions to undergo surgery or when they refuse it. By treating the tumor, with this minimally invasive technique, we are stopping its growth and avoiding disease progression.

Microwave ablation of solitary T1N0M0 papillary thyroid carcinoma: A case report

BACKGROUND

The gold standard treatment for papillary thyroid carcinoma is total thyroidectomy and indications for microwave thermal ablation for primary thyroid cancers have not yet been clearly established However, some patients refuse surgery and others have no indication for it, for example patients under palliative care as in this case, or cannot undergo surgery, based on their comorbidities. These indications are described in the most recent Korean, North American and European guidelines. Laser ablation, radiofrequency ablation, and microwave ablation are similarly safe and effective, so the choice should be based on the specific competences and resources of the pertaining centers. These indications are Percutaneous minimally-invasive techniques; they can be useful to stop disease progression and as an alternative to surgery in patients with contraindication or who refuse surgery. We present a case of a thyroid papillary carcinoma with 17 mm effectively treated with microwave thermal ablation and without recurrence after one year of follow up.

CASE SUMMARY

The authors present a case of a 71-years-old patient with a left lobe papillary thyroid carcinoma with 13 mm × 17 mm × 13 mm, with no indication for thyroid surgery given the context of another cancer in palliative treatment. Microwave thermoablation was performed on December 2021. Four months later he repeated computed tomography (CT) scan, which showed that the tumor had disappeared. Six months after ablation he underwent a positron emission tomography/CT-fluorodeoxyglucose scan, which didn’t show any evidence of hypermetabolic tumor lesions.

CONCLUSION

This case shows microwave thermoablation can be a safe and effective alternative to surgery in patients with no conditions to undergo surgery or when they refuse it. By treating the tumor, with this minimally invasive technique, we are stopping its growth and avoiding disease progression.

Thyroid cancer

The past 5-10 years have brought in a new era in the care of patients with thyroid cancer, with the introduction of transformative diagnostic and management options. Several international ultrasound-based thyroid nodule risk stratification systems have been developed with the goal of reducing unnecessary biopsies. Less invasive alternatives to surgery for low-risk thyroid cancer, such as active surveillance and minimally invasive interventions, are being explored. New systemic therapies are now available for patients with advanced thyroid cancer. However, in the setting of these advances, disparities exist in the diagnosis and management of thyroid cancer. As new management options are becoming available for thyroid cancer, it is essential to support population-based studies and randomised clinical trials that will inform evidence-based clinical practice guidelines on the management of thyroid cancer, and to include diverse patient populations in research to better understand and subsequently address existing barriers to equitable thyroid cancer care.

Ultrasound-Guided Radiofrequency and Microwave Ablation for the Management of Patients With Benign Thyroid Nodules: Systematic Review and Meta-Analysis

ABSTRACT

Ultrasound-guided thermal ablation has been shown to considerably reduce nodule-related discomfort and cosmetic problems. Hence, this review was done to determine the effectiveness of ultrasound-guided radiofrequency or microwave ablation in the management of benign thyroid nodules. Searches were done in EMBASE, SCOPUS, PubMed Central, Cochrane library, MEDLINE, Google Scholar, ScienceDirect, and Clinicaltrials.gov until August 2022. Meta-analysis was carried out using random-effects model. With 95% confidence intervals (CIs), pooled standardized mean differences, mean differences, and/or odds ratio reported. In total, we analyzed 16 studies, most of them had high risk of bias. The pooled standardized mean difference for symptom score was -1.01 (95% CI, -1.83 to -0.19; I2 = 94.2%), for cosmetic relief was -1.26 (95% CI, -2.27 to -0.24; I2 = 96%), for postoperative nodule volume was -1.77 (95% CI, -3.06 to -0.48; I2 = 94%), for hospital stay was -3.88 (95% CI, -4.58 to -3.18; I2 = 91.1%), for operation time was -3.30 (95% CI, -3.95 to -2.64; I2 = 93.4%). The pooled odds ratio for postoperative pain was 0.04 (95% CI, 0.00-0.35; I2 = 95.1%), for postoperative hypothyroidism was 0.04 (95% CI, 0.01-0.11; I2 = 0%), for postoperative hoarseness was 0.56 (95% CI, 0.22-1.47; I2 = 0%), for postoperative hematoma was 0.57 (95% CI, 0.15-2.22; I2 = 0%). Ultrasound-guided radiofrequency and microwave ablation had better efficacy and safety profile in terms of symptoms, cosmetic relief, complication rate, duration of stay, and operation time when compared with conventional surgery or observation without treatment for patients with benign thyroid nodules.

Upgraded hydrodissection and its safety enhancement in microwave ablation of papillary thyroid cancer: a comparative study

OBJECTIVES

To study the efficacy and safety of an improved hydrodissection protocol based on the perithyroidal fascial space during microwave ablation for papillary thyroid carcinoma (PTC).

METHODS

The data of 341 patients (94 men and 247 women, median age 41 years old, 25%-75% interquartile range 34-53 years old, nodule maximum diameter 0.2-1.9 cm) who underwent microwave ablation for PTC were retrospectively reviewed. Among them, 185 patients underwent traditional hydrodissection and served as a control group, and 156 patients underwent improved hydrodissection based on perithyroidal fascial spaces, constituting the improved group. Improvements in safety were analyzed by comparing complications between the two groups. The characteristics of hydrodissected spaces, complications, and follow-up results were recorded.

RESULTS

Hydrodissection was successfully performed in all enrolled patients according to the protocol. The incidence of hoarseness caused by recurrent laryngeal nerve injury, the most common complication in thermal ablation of thyroid nodules, was significantly lower in the improved group than in the control group (1.9% vs. 8.1%, p = 0.021). The median hoarseness recovery time in the improved group was shorter than that in the control group (2 months vs. 3 months, p = 0.032). During follow-up, no local recurrence was encountered in either group. The tumor disappearance rate was not significantly different between the two groups (69.9% vs. 75.7%, p = 0.228).

CONCLUSIONS

Improved hydrodissection based on perithyroidal fascial spaces had better protective effects than traditional hydrodissection.

A clinical study on microwave ablation of multifocal (≤ 3) T1N0M0 papillary thyroid carcinoma

OBJECTIVE

To evaluate the feasibility, efficiency, and safety of microwave ablation (MWA) for T1N0M0 multifocal (≤ 3) papillary thyroid carcinoma (PTC).

METHODS

This was a retrospective study, and patients who underwent MWA for multifocal (≤ 3) PTC were reviewed between October 2016 and December 2020. After ablation, the changes in tumor size and volume, as well as the rate of technical success, tumor disappearance, disease progression, and complications were assessed.

RESULTS

There were a total of 57 cases enrolled in the present study, which included 18 males and 39 females. The mean age was 44 ± 11 years (22-66 years); the mean follow-up time was 18 ± 11 months (6-48 months). Complete ablation was achieved in all enrolled cases. Therefore, the technical success rate was 100%. Due to expanding ablation, the MD and volume of the ablation zone, as well as the VRR, increased at the 1st and 3rd months after ablation and decreased at 12 and 18 months after ablation (p < 0.05 for all). The total complete tumor disappearance rate was 43.9% (25/57), including 54% (24/44) in the T1a subgroup vs. 7.7% (1/13) in the T1b subgroup (p = 0.003). The total disease progression rate was 7% (4/57), including 9.1% (4/44) in the T1a subgroup vs. 0% (0/13) in the T1b subgroup (p = 0.142). The overall complication rate was 5.3% (3/57), including 6.8% (4/44) in the T1a subgroup vs. 0% (0/13) in the T1b subgroup (p = 0.206).

CONCLUSION

This preliminary study indicates that MWA is a safe and effective treatment for T1N0M0 multifocal (≤ 3) PTC.

KEY POINTS

• MWA is a promising alternative method for T1N0M0 multifocal (≤ 3) PTC.

Microwave Ablation versus Surgical Resection for Solitary T1N0M0 Papillary Thyroid Carcinoma

Background Microwave ablation (MWA) has attracted interest as a minimally invasive treatment for papillary thyroid carcinoma (PTC). However, comparisons between MWA and surgical resection (SR) in the management of T1N0M0 PTC are rare. Purpose To compare the technical effectiveness, disease progression, and complications of MWA and SR for solitary T1N0M0 PTC. Materials and Methods This retrospective study was conducted in a single center. A total of 1029 patients with T1N0M0 PTC treated with either MWA or SR from January 2015 to May 2021 were studied and divided into two groups according to treatment modality. Propensity score matching and inverse probability of treatment weighting were used to control for confounding factors. Disease progression was analyzed in T1N0M0 PTCs as well as T1a and T1b subgroups by using Kaplan-Meier curves and Cox proportional hazards regression models. Results A total of 404 patients (mean age, 43 years ± 12 [SD]; 289 women; 337 with T1a PTC) underwent MWA, and 625 (mean age, 46 years ± 12; 495 women; 521 with T1a PTC) underwent SR. During the follow-up (median, 25 months; IQR, 7-61 months), there was no evidence of differences regarding disease progression in T1N0M0 (4.0% vs 4.0%; P = .97), T1a (3.4% vs 3.8%; P = .89), or T1b PTCs (6.8% vs 5.0%; P = .72). Compared with SR, MWA resulted in less blood loss (2 mL vs 10 mL) and a shorter procedure time (23 minutes vs 72 minutes) (both P < .001). The rate of major complications was 5.4% (19 of 350 patients) in the MWA group and 6.3% (22 of 350 patients) in the SR group (P = .75). Permanent hoarseness only occurred in the SR group (1.7%; P = .03). Conclusion For T1a and T1b solitary T1N0M0 papillary thyroid carcinomas, there was no evidence of differences regarding disease progression and major complications between microwave ablation and surgical resection. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by vanSonnenberg and Simeone in this issue.

Comparison of ultrasound-guided radiofrequency ablation versus thyroid lobectomy for T1bN0M0 papillary thyroid carcinoma

OBJECTIVE

To investigate and compare the clinical outcomes between radiofrequency ablation (RFA) and thyroid lobectomy (TL) for T1bN0M0 papillary thyroid carcinoma (PTC).

METHODS

This retrospective study evaluated 283 patients with solitary T1bN0M0 PTC treated with RFA (RFA group, 91 patients) or TL (TL group, 192 patients) from May 2014 to November 2018. The patients were regularly followed up after treatment. Local tumor progression, lymph node metastasis (LNM), recurrent tumor, persistent tumor, recurrence-free survival (RFS), treatment variables (hospitalization, procedure time, estimated blood loss, and cost), complication, and delayed surgery were compared.

RESULTS

During the follow-up (median [interquartile ranges], 50.4 [18.0] months), no significant differences were found in the local tumor progression (4.4% vs 3.6%, p = 1.000), LNM (1.1% vs 2.1%, p = 0.917), recurrent tumor (2.2% vs 1.6%, p = 1.000), persistent tumor (1.1% vs 0%, p = 0.146), and RFS rate (95.6% vs 96.4%, p = 0.816) in the RFA and TL groups. Distant metastasis was not detected. Patients in the RFA group had a shorter hospitalization (0 vs 7.0 [3.0] days, p < 0.001), shorter procedure time (5.6 [2.9] vs 90.0 [38.5] min, p < 0.001), lower estimated blood loss (0 vs 20 [20] mL, p < 0.001), lower cost ($1972.5 [0.1] vs $2362.4 [1009.3], p < 0.001), and lower complication rate (0 vs 12/192 [6.3%], p = 0.015) than those in the TL group. No patients in the RFA group underwent delayed surgery.

CONCLUSIONS

This study revealed comparable 4-year clinical outcomes between RFA and TL for T1bN0M0 PTC in terms of local tumor progression and RFS. As a minimally invasive modality, RFA may be a promising feasible alternative to surgery for the treatment of T1bN0M0 PTC in selected patients after strict evaluation.

KEY POINTS

• No significant difference in local tumor progression and RFS was found between RFA and TL for T1bN0M0 PTC during a median follow-up period of 50.4 months. • Compared with TL, RFA led to a shorter hospitalization, lower estimated blood loss, lower cost, and lower complication rate. • RFA may be a promising feasible alternative to surgery for the treatment of T1bN0M0 PTC in selected patients after strict evaluation.

Research Review of Thermal Ablation in the Treatment of Papillary Thyroid Carcinoma

Background

Minimally invasive treatment of thyroid tumors has become increasingly common, but has mainly focused on benign thyroid tumors, whereas thermal ablation of thyroid cancer remains controversial. Clinical studies analyzing the efficacy of thermal ablation of papillary thyroid carcinoma (PTC) have been conducted in several countries to verify its safety. Here, we screened and reviewed recent studies on the efficacy and safety of thermal ablation of PTC as well as psychological assessment, patient prognosis, recurrence, and factors affecting ablation.

Summary

The most significant controversy surrounding ablative treatment of PTC centers on its effectiveness and safety, and >40 studies have been conducted to address this issue. The studies include papillary thyroid microcarcinoma (PTMC) and non-PTMC, single PTC and multiple PTC, and controlled studies of ablative therapy and surgical treatment. In general, ablation techniques can be carefully performed and promoted under certain conditions and with active follow-up of postoperative patients. Ablation is a promising alternative treatment especially in patients who are inoperable.

Conclusions

Clinical studies on PTC ablation have provided new perspectives on local treatment. However, because PTC grows very slowly, it is an indolent tumor; therefore, studies with larger sample sizes and extended post-procedure follow-ups are necessary to confirm the investigators’ hypotheses.

Microwave ablation vs. surgery for papillary thyroid carcinoma with minimal sonographic extrathyroid extension: a multicentre prospective study

OBJECTIVES

Minimal extrathyroid extension (mETE) was removed from the TNM staging system. This study was designed prospectively to compare the safety and efficacy of microwave ablation (MWA) versus surgery for treating T1N0M0 papillary thyroid carcinomas (PTC) with sonographically detected mETE.

METHODS

From December 2019 to April 2021, 198 patients with T1N0M0 mETE-PTCs evaluated by preoperative ultrasound from 10 hospitals were included. Ninety-two patients elected MWA, and 106 patients elected surgery for treatment. MWA was performed using extensive ablation with hydrodissection. Surgery consisted of lobectomy with ipsilateral central lymph node dissection (CLD), lobe and isthmus excision with ipsilateral CLD and total thyroidectomy with ipsilateral CLD. The rates of technical success, cost, oncologic outcomes, complications and quality of life of the two groups were assessed.

RESULTS

The follow-up times for the MWA and surgery groups were 12.7 ± 4.1 and 12.6 ± 5.0 months, respectively. The technical success rate was 100% for both groups. Oncological outcomes of the two groups were similar during the follow-up (all p > 0.05). The MWA group had a shorter operation time, less blood loss and lower costs (all p < 0.001). Three complications (3.3%) were reported in the MWA group and 4 (3.8%) in the surgery group (p = 0.846). The surgery group had higher scores for scar problems and anxiety (p < 0.001 and p = 0.003, respectively).

CONCLUSIONS

Microwave ablation was comparable in the short term to surgery in terms of treatment safety and efficacy in selected patients with T1N0M0 mETE-PTC detected by ultrasound.

KEY POINTS

• Microwave ablation is comparable to surgery in the safety and short-term efficacy for PTCs with sonographically detected mETE. • Thermal ablation is technically feasible for mETE-PTC treatment. • Patients with mETE-PTC have similar quality of life in the two groups, except for worse scar problems and anxiety in the surgery group.

Recurrent Laryngeal Nerve Injury in Thermal Ablation of Thyroid Nodules-Risk Factors and Cause Analysis

CONTEXT

Recurrent laryngeal nerve (RLN) injury is a complication of thermal thyroid nodule treatment.

OBJECTIVE

We investigated the influencing factors of RLN injury in patients who underwent thermal ablation of thyroid nodules.

METHODS

The data of 1004 patients (252 male, 752 female; median age 44 years) who underwent thermal thyroid nodule ablation were retrospectively reviewed. Patients were divided into benign cystic, benign solid, and papillary thyroid cancer (PTC) groups. The parameters related to RLN injury were analyzed, including the largest diameter, location of the nodules, and shortest distance of the nodule to thyroid capsule and tracheoesophageal groove (TEG). Univariate and multivariate analyses were performed to select risk factors for RLN injury.

RESULTS

The RLN injury rate was higher in PTC (6.3%) than in benign cystic (1.2%, P = 0.019) and solid nodules (2.9%, P = 0.018). PTC subgroup analysis showed that the RLN injury rate was higher in T1b (10.7%) and T2 (28.6%) PTC than in T1a PTC (5.0%, P < 0.05). In the PTC group, TEG distance, anterior capsule distance, median capsule distance, posterior capsule distance, and maximum nodule diameter were risk factors for RLN injury. The logistic regression fitting of the nomogram showed high prediction efficiency (C-Index 0.876). The main cause of RLN injury was insufficient medial isolating fluid (MIF). The safety thicknesses of MIF for benign cystic, benign solid, and PTC nodules were 3.1 mm, 3.7 mm, and 3.9 mm, respectively.

CONCLUSION

Several risk factors for RLN injury should be considered before thermal ablation of thyroid nodules. The RLN injury rate could be predicted with the nomogram.

Minimally Invasive Techniques for the Management of Thyroid Nodules

Image-guided interventional techniques have emerged as promising treatments for thyroid disease. Percutaneous ethanol ablation, radiofrequency ablation, laser ablation, high intensity focused ultrasound, and microwave ablation have shown efficacy in treating benign thyroid disease. There is increasing evidence that these techniques may effectively treat papillary thyroid microcarcinomas, recurrent and metastatic disease, follicular neoplasms, and parathyroid lesions. They are performed in an outpatient setting, well-tolerated, with negligible risk for thyroid hormone supplementation, making them a popular alternative to surgical resection. In this comprehensive review, we discuss the devices, techniques, advantages, and disadvantages of each intervention, and summarize the published outcomes.

Thermal ablation for papillary thyroid microcarcinoma located in the isthmus: a study with 3 years of follow-up

Aims: To analyze the outcomes of thermal ablation for isthmic papillary thyroid microcarcinoma (PTMC). Patients & methods: Data for 21 isthmic-PTMC patients who underwent microwave ablation under ultrasound guidance were retrospectively collected. General information on patients and characteristics of tumors were collected. The technical effectiveness, tumor recurrence and volume changes and postoperative complications were recorded during the follow-up. Comparisons with 105 nonisthmic-PTMCs were done. Results: The technical effectiveness was 100%. No recurrence or lymph node metastases were detected. Tumor volume decreased significantly with a volume reduction rate of 1.00 ± 0.01 (range: 0.99 to 1.0) at the final evaluation and seven cases (31.8%) were completely resolved. No complication was encountered. No statistical differences were observed in terms of complications, recurrence or the volume reduction rate compared with the nonisthmic group (all p > 0.05). Conclusions: Percutaneous microwave ablation is an effective treatment strategy for isthmic-PTMC.

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.

Changes in Thyroid Antibodies after Microwave Ablation of Thyroid Nodules

PURPOSE

Microwave ablation (MWA) is a minimally invasive method for the thermal ablation of benign thyroid nodules and papillary thyroid cancer (PTC) and has shown promising results. The aim of this study was to investigate the impact of MWA on thyroid antibodies and associated influencing factors.

MATERIALS AND METHODS

A total of 119 patients, including 69 with benign thyroid nodules and 50 with PTC, underwent MWA between June 2019 and June 2021. The serum levels of (free) triiodothyronine, (free) thyroxine, thyrotropin, and antibodies against Tg (TGAb), thyrotropin receptors (TRAb), and thyroid peroxidase (TPOAb) were measured during the follow up.

RESULTS

One month after ablation, three patients (4.3%) in the benign group had hypothyroidism, and one (1.4%) had hyperthyroidism. Four patients (5.8%) had subclinical hypothyroidism, and two (2.9%) had subclinical hyperthyroidism. Among the PTC patients, two (4%) had hypothyroidism, and one (2%) had hyperthyroidism. Two patients (4%) had subclinical hypothyroidism, and one (2%) had subclinical hyperthyroidism. In the benign group, among patients with normal preablation antibodies, the postablation TGAb abnormal rate was 12.7%, the TPOAb level was 4.8%, and the TRAb level was 0%. Among PTC patients, the postablation TGAb abnormal rate was 11.4%, the TPOAb level was 8.7%, and the TRAb level was 4.0%. The cutoff value of preablation TGAb for predicting postoperative antibody abnormalities was 19.0 IU/mL, while that of TPOAb was 11.4 IU/mL.

CONCLUSIONS

MWA of thyroid nodules had little influence on thyroid function and antibodies. Elevations in TGAb, TPOAb, and TRAb beyond the normal ranges after MWA may be related to high preablation levels of TGAb and TPOAb.

Over than three-year follow-up results of thermal ablation for papillary thyroid carcinoma: A systematic review and meta-analysis

BACKGROUND

This study is a meta-analysis based on evidence-based medicine to explore the long-term (≥3 years) efficacy of thermal ablation in the treatment of papillary thyroid carcinoma (PTC).

METHODS

We searched the PubMed, Embase, and Cochrane Library databases for studies published during the time between the establishment of the databases through June 2022. We included 13 non-randomized-controlled trials (non-RCTs) that reported the application of ultrasound-guided thermal ablation in PTC. We excluded studies that were repeated publications, research without full text, contained incomplete information, lacked data extraction, involved animal experiments, reviews, and systematic reviews. STATA 15.1 software was used to analyze the data.

RESULTS

Tumor volume after thermal ablation at 3-year follow-up was significantly lower than pre-ablation (standardized mean difference [SMD] = -1.06, 95% CI: -1.32~-0.80). The pooled results indicated that the maximum diameter after thermal ablation at 3-year follow-up was significantly lower than pre-ablation (SMD = -1.93, 95% CI: -12.13~-1.73). The pooled results indicated that volume reduction rate (VRR) after thermal ablation at 3-year follow-up was 98.91% (95% CI: 97.98-99.83%), and complete disappearance rate (CDR) after thermal ablation at 3-year follow-up was 83% (95% CI: 67-94%). In addition, the incidence of newly discovered mPTC and lymph node metastases after thermal ablation was 0.3% (95% CI: 0.0-1.0%) and 0.0% (95% CI: 0.0-0.0%), respectively.

CONCLUSION

Overall, the long-term (≥3 years) efficacy of ultrasound-guided thermal ablation in the treatment of PTC was significant, with favorable disease progression. Ultrasound-guided thermal ablation can be considered an alternative approach for patients with PTC who refuse surgery or are unable to undergo surgery.

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.

A comprehensive review of interventional ablation techniques for the management of thyroid nodules and metastatic lymph nodes

Thyroidectomy remains the gold standard treatment for benign, symptomatic, or enlarging thyroid nodules, malignant nodules, and metastatic lymph node disease. However, in the past 2 decades, image-guided interventional techniques have emerged as promising alternative treatments for these conditions. Percutaneous ethanol ablation is now an accepted first-line treatment for recurring cystic thyroid nodules. Thermal ablation techniques such as high-intensity focused ultrasound, laser ablation, radiofrequency ablation, and microwave ablation have shown efficacy in producing a nodular volume reduction of greater than 50% that is maintained for several years with resolution of local compressive symptoms. There is also increasing evidence that these techniques can effectively treat papillary thyroid microcarcinomas and recurrent metastatic lymph node disease. Because these interventional ablation techniques are performed safely in an outpatient setting, are well tolerated, and the risk for needing thyroid hormone supplementation is negligible, they are becoming a popular alternative treatment to surgical resection. In this comprehensive review, we discuss each of these percutaneous interventions: the devices and techniques, the advantages and disadvantages of each energy, and summarize the outcomes published in the literature.

Analysis and evaluation of the efficacy of ultrasound-guided microwave ablation for papillary thyroid microcarcinoma

OBJECTIVE

The choice of the most appropriate therapeutic approach for a diagnosed papillary thyroid microcarcinoma (PTMC) remains controversial. The present study aimed to evaluate the efficacy of microwave ablation (MWA) for unifocal PTMC with a diameter of ≤0.6 cm.

METHODS

A total of 63 consecutive patients with PTMC treated with MWA were studied retrospectively. MWA was performed using the hydrodissection technique and multidimensional fixed-needle principle. We analyzed the absorption of the MWA area and evaluated the prognosis over a follow-up period of 24 months. In addition, 83 patients with PTMC who underwent surgery were selected. The operating room characteristics and procedural complications of the two groups were compared.

RESULTS

In the MWA group, the volume of nodules (p < 0.05) decreased from 0.04 ± 0.03 cm³ to 0.0001 ± 0.0004 cm³ at the 24-month follow-up after MWA, and the volume reduction rate (p < 0.05) was 99.43 ± 1.58%. The incidence of temporary reactive hyperplastic lymphadenectasis was higher and that of other complications was lower in the MWA group than in the surgery group. One percent of the patients in the surgery group had recurrence or metastasis, but none were detected in the MWA group. The loss of thyroid tissue volume (p < 0.001), operating room time (p < 0.001), and the mean length of hospital stay (p < 0.001) were significantly lower in the MWA group than in the surgery group.

CONCLUSION

Ultrasound-guided MWA is an effective treatment strategy for unifocal PTMC with a diameter of ≤0.6 cm.

A feasibility study of microwave ablation for papillary thyroid cancer close to the thyroid capsule

BACKGROUND

To evaluate the feasibility, efficiency, and safety of microwave ablation (MWA) for papillary thyroid carcinoma (PTC) close to the thyroid capsule.

METHODS

The data of 106 cases who underwent thermal ablation from June 2014 to September 2020 were retrospectively analyzed. The mean follow-up time was 25 ± 11 months (range, 9-48 months). The strategy of fluid isolation was successfully applied in all cases, and all PTC nodules underwent extended ablation. The technical feasibility, technical success rate, and safety were analyzed. Changes in tumor size at different time points after MWA were evaluated.

RESULTS

According to the contrast-enhanced ultrasound results after ablation, MWA has been successfully applied in all enrolled cases. The capsular ablation has also been achieved for all cases. Nodules in 71 cases (70.0%) completely disappeared in the follow-up period. No local recurrence was detected. The incidence of lymph node metastasis and new tumors was 1.9% (2/106) respectively. Light voice changes were the only complication, with a rate of 5.7% (6/106), which were relieved within 6 months after MWA. The size of the ablation zone increased firstly in 6 months after MWA compared with the pretreatment tumor size (p < 0.05). At 12, 18, 24, 30, 36 and 42 months after MWA, the ablation zone shrank and the sizes were smaller than the tumor size before MWA (p < 0.05 for all).

CONCLUSIONS

MWA is an effective, safe, and feasible method in treating PTC close to the thyroid capsule.

Ultrasonography-guided radiofrequency ablation for the treatment of T2N0M0 papillary thyroid carcinoma: a preliminary study

PURPOSE

To evaluate the efficacy and safety of ultrasonography (US)-guided radiofrequency ablation (RFA) for treating T2N0M0 papillary thyroid cancer (PTC).

METHODS

This retrospective study was approved by the ethics committee of Chinese PLA General Hospital (S2019-211-01). Twelve patients with T2N0M0 PTC (five men and seven women with a mean age of 41.0 ± 9.2 years (range, 21-61 years)), who were not eligible for or refused surgery, were included in our study. RFA was performed with the moving-shot technique, and the ablation area exceeded the tumor edge by at least 3 mm. US was performed before RFA, immediately, 1, 3 , 6 and 12 months after RFA, and every 6-12 months thereafter.

RESULTS

All tumors were ablated as planned. The mean follow-up duration was 24.1 ± 6.9 months (range, 13-33 months). The tumor volume decreased significantly from 4.4 ± 2.8 ml to 0.3 ± 0.5 ml, and the volume reduction rate (VRR) was (93.7 ± 7.6)% at the final follow-up with two tumors (16.7%) disappearing. New or recurrent tumors were not found, and no local or distant metastasis were detected during follow-up. No life-threatening or delayed complications were observed.

CONCLUSION

RFA may be a potential alternative to surgery for the management of T2N0M0 PTC in select patients, especially for those who are ineligible for surgery.

Ultrasound-guided thermal ablation for papillary thyroid microcarcinoma: a multicenter retrospective study

PURPOSE

Ultrasound-guided thermal ablation (including microwave ablation [MWA] and radiofrequency ablation [RFA]) has emerged as a remarkable technology for the treatment of benign and malignant diseases. The objective of this multicenter study was to assess the efficacy and safety of thermal ablation in a large cohort of patients with papillary thyroid microcarcinoma (PTMC).

MATERIALS AND METHODS

Retrospective study of 725 patients who underwent MWA/RFA at 11 centers between March 2015 and March 2020. The mean age of patients was 46 ± 11 years (range, 22-81); the mean follow-up time was 21 ± 13 months (range, 6-60). Changes in size of tumor, the rates of tumor disappearance, disease progression, and complications were assessed.

RESULTS

From 6 months post-ablation, the size of tumors was significantly reduced compared with those recorded pre-ablation (p < 0.001 for all). Five hundred and fifteen (71.0%) PTMCs had completely disappeared as assessed by ultrasound examination. Six (0.8%) patients developed disease progression post-ablation; of these, 5 (0.7%) patients developed new PTMCs, while one (0.1%) patient developed cervical lymph node metastasis. Nineteen (2.6%) patients developed complications post-ablation; of these 14 (1.9%) patients developed voice hoarseness, 4 (0.6%) developed hematoma, and one (0.1%) patient developed cough.

CONCLUSIONS

Ultrasound-guided thermal ablation represents an effective and safe treatment for patients with PTMC besides active surveillance and surgery.

Efficacy and safety of radiofrequency ablation in the treatment of low-risk papillary thyroid carcinoma: a review

Ultrasound-guided radiofrequency ablation (RFA) has recently been used for the treatment of thyroid carcinomas. In this study, we aimed to evaluate the efficacy and safety of RFA for treating low-risk papillary thyroid carcinomas (PTCs). We searched the MEDLINE and the SCOPUS databases up to December 29, 2020, for studies assessing the efficacy and safety of RFA in the management of low-risk PTCs. Data on volume reduction ratio (VRR), complete disappearance, carcinoma recurrence, and complication frequency were collected. Thirteen studies with a total of 1389 patients and 1422 tumors were included in the synthesis of this study. Mean VRR varied between 47.8 and 100%, with most studies reporting a ratio of 98.5-100%. The ratio of complete disappearance ranged between 33.7 and 100%, although studies with a prolonged follow-up period reported a frequency of 56-100%. The tumor progression/recurrence frequency was 0-4.5%. Complications occurred in 45 patients (3.2%). Mild-moderate pain and cervical discomfort were the most common complications and no life-threatening complications were reported. Based on these data, we suggest that ultrasound-guided RFA can serve as an efficacious and safe alternative for the treatment of low-risk PTC in patients who are unable or unwilling to receive surgical therapy.

Microwave ablation for papillary thyroid cancer located in the thyroid isthmus: a preliminary study

PURPOSE

To assess the feasibility, efficacy, and safety of ultrasound (US)-guided microwave ablation (MWA) for the treatment of papillary thyroid cancer (PTC) located in the thyroid isthmus.

MATERIALS AND METHODS

Thirty-four patients (mean age, 43 ± 11 years; 26 women) with isthmic PTC treated with MWA between June 2014 and September 2020 were included in this retrospective study. The follow-up time after MWA was 17 ± 9 months (range, 8-50 months). Changes in thyroid function, parathyroid function, and tumor size were evaluated, along with the rates of tumor disappearance and complications.

RESULTS

The treatment was technically feasible and successfully completed in all 34 patients (100%). Measures of thyroid function (i.e. serum triiodothyronine, free thyroxine, and thyrotropin) and parathyroid function (i.e. serum calcium and intact parathyroid hormone) showed no changes from pretreatment levels at 1, 3, and 6 months after MWA (p > 0.05 for all). Tumor size was found to be increased at 1 and 3 months after MWA compared with before MWA (p < 0.05). However, the tumor sizes measured at 6, 9, 12, and 18 months after MWA were smaller than the pretreatment sizes (p < 0.05 for all). In 24 cases (70.6%), the tumors completely disappeared on US examination. Five cases (2.9%) experienced side effects from MWA treatment, but no major or minor complications were recorded.

CONCLUSION

The results of this study demonstrate that US-guided MWA is a feasible, effective, and safe treatment option for selected patients with PTC located in the thyroid isthmus.

Ultrasound-Guided Radiofrequency Ablation Versus Surgical Resection for the Treatment of T1bN0M0 Papillary Thyroid Carcinoma in Different Age Groups

PURPOSE

We aimed to compare the efficacy and safety of radiofrequency ablation (RFA) to that of surgical resection (SR) in patients with T1bN0M0 papillary thyroid carcinoma (PTC) in different age groups.

METHODS

Totally, 204 patients with an isolated, solitary, intrathyroidal T1bN0M0 PTC, who underwent either RFA (n=94) or SR (n=110) between April 2014 and December 2019, were retrospectively enrolled and were divided into two subgroups according to age (<45 years, ≧45 years). Patients with pathologically aggressive or advanced lesions were excluded from the study. Tumor progression and procedural complications were the primary and secondary endpoints, respectively. Tumor recurrence in situ, newly discovered tumors, lymph node involvement, or distant metastases indicated tumor progression. Complications included pain, fever, voice change, choking, numbness in the limbs, and cardiac events. Incidence rates of all endpoint events were compared between different age subgroups.

RESULTS

There were no significant differences in age, sex, and tumor size between the treatment groups. While the RFA group incurred less cost and experienced significantly shorter operative duration than the SR group, no significant differences were observed in incidences of both tumor progression and complications. Further, subgroup analysis of patients <45 years versus those ≧45 years showed no significant differences in the incidence of tumor progression and complications within or between different treatment groups. Older patients in the SR group incurred higher hospital costs than younger counterparts, but this difference was not observed in the RFA group.

CONCLUSIONS

Our results indicated that RFA had a similar prognosis as that of SR but was associated with lower overall cost in both young (<45 years) and middle-aged patients (≧45 years) with T1bN0M0 PTC. Therefore, RFA may be an effective and safe alternative to surgery for the treatment of patients with T1bN0M0 PTC.