Ultrasound-guided percutaneous laser ablation of unifocal T1N0M0 papillary thyroid microcarcinoma: Preliminary results

Efficacy and Oncologic Outcomes of Thermal Ablation Techniques in the Treatment of Primary Low-Risk Papillary Thyroid Carcinoma: A Systematic Review and Network Meta-Analysis

BACKGROUND

This study aimed to evaluate the safety, efficacy, and oncologic outcomes of thermal ablation techniques, including radiofrequency, laser, and microwave ablation, in treating primary thyroid cancer compared with surgical resection.

METHOD

We conducted a systematic review and network meta-analysis, which included 21 comparative studies and 40 noncomparative studies.

RESULTS

The three thermal ablation techniques showed significant superiority over surgical resection in terms of operative time, pain, cost, quality of life, and complications. Three years after the procedure, the tumor volume reduction and complete disappearance rates for the three thermal ablation techniques were similar, at approximately 99% and 93%-95%, respectively. The recurrence rate remained comparable (approximately 2%-3%) among the three thermal ablation techniques and surgical resection during a follow-up period exceeding 3 years.

CONCLUSIONS

The safety, efficacy, and oncologic outcomes of thermal ablation techniques may be acceptable and comparable to surgical resection for selected cases of primary thyroid cancer.

Thermal Ablation for Papillary Thyroid Carcinoma

Importance

Image-guided thermal ablation has been administered for patients with T1N0M0 papillary thyroid carcinoma (PTC) who elect to not undergo surgery or receive active surveillance. Considering the indolent nature of PTC, long-term outcomes of ablation are needed.

Objective

To investigate l0-year outcomes of thermal ablation in treating T1N0M0 PTC.

Design, Setting, and Participants

This multicenter study was conducted at 4 university-affiliated hospitals in China and included 179 consecutive patients with T1N0M0 PTC (median [IQR] volume, 88.0 [163.2] mm3) who underwent thermal ablation between June 2010 and March 2014. Patients who were ineligible to undergo surgery or elected not to were included, and patients had PTC tumors that were smaller than 20 mm as confirmed by biopsy; no clinical or imaging evidence of extrathyroidal extension, lymph node metastasis (LNM), or distant metastasis; and no history of neck irradiation.

Main Outcomes and Measures

The primary outcomes were disease progression (LNM, newly developed tumors, persistent tumors, and distant metastasis) and disease-free survival (DFS). Secondary outcomes were technical success, volume reduction rate, tumor disappearance, complications, and delayed surgery. DFS was calculated using a Kaplan-Meier analysis.

Results

Among the 179 patients, the mean (SD) age was 45.8 (12.7) years, and 118 (65.9%) were female. During a mean (SD) follow-up period of 120.8 (10.8) months, disease progression was found in 11 of 179 patients (6.1%), including LNM in 4 patients (2.2%), newly developed tumors in 6 patients (3.3%), and persistent tumor in 1 patient (0.6%). The 10-year DFS was 93.9%. The technical success, median volume reduction rate, and tumor disappearance rate was 100%, 100%, and 97.2%, respectively. The magnitude of the disease progression (6.1% vs 7.1%; difference, 1.0%; 95% CI, -6.5% to 25.6%) and DFS (93.9% vs 92.9%; difference, 1.0%, 95% CI, -6.5% to 25.6%) between patients with T1a and T1b tumors was small. The difference in the rate of tumor disappearance between T1a and T1b tumors was large (99.4% vs 71.4%; difference, 28.0%; 95% CI, 10.9%-54.0%). One patient experienced transient voice hoarseness (0.6%). Because of anxiety, 1 patient underwent delayed surgery (0.6%).

Conclusions and Relevance

The results of this 10-year multicenter cohort study suggest that thermal ablation is an effective and safe alternative for patients with T1N0M0 PTC who do not undergo surgery or receive active surveillance. For safe and effective treatment, accurate radiologic evaluation, an understanding of ablation techniques, and experienced physicians are recommended.

Management of low-risk papillary thyroid cancer. Minimally-invasive treatments dictate a further paradigm shift?

BACKGROUND

Current management options for PTMC include lobo-isthmectomy and active surveillance (AS). Recently, ultrasound-guided minimally invasive procedures (MITs) are offered as a nonsurgical therapy for PTMC because they do not require hospitalization and general anaesthesia, and do not result in loss of thyroid function or cosmetic damage. MITs are reported to consistently provide, mostly in large retrospective series of patients, a rapid, safe, and cost-effective way to eradicate low-risk thyroid malignancies. However, conclusive data from well-conducted prospective studies on the histologically-proven completeness of tumor ablation and the long-term clinical advantages versus AS are still lacking.

OBJECTIVES

This study aimed to evaluate the efficacy and safety of ultrasound-guided minimally invasive treatments (MITs) for PTMC in comparison to traditional surgical methods and active surveillance, and to assess their role in current clinical practice.

METHODS

A structured literature review was conducted using keywords related to PTMC, MIT, and comparative techniques. Studies were evaluated based on treatment modality, patient selection, follow-up duration, complication rates, and clinical outcomes.

RESULTS

MITs have shown promising results in the management of PTMC. These treatments offer several advantages over surgery, such as reduced use of surgical resources, lower costs, minimal work disruption, and fewer major complications. However, there are still limitations, including the need for long-term surveillance and the potential risk of incomplete tumor ablation.

CONCLUSIONS

MITs represent a promising non-surgical option for managing low-risk PTMC, especially for patients ineligible for or refusing surgery. Despite favorable outcomes, more robust prospective data are needed to confirm their long-term benefits and completeness of tumor ablation. Interdisciplinary discussions and thorough patient education on the advantages and limitations of MITs are crucial for informed decision-making.

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.

Preclinical assessment of a mathematical model for ablation zone prediction in thyroid laser ablation

To develop and validate a 3D simulation model to calculate laser ablation (LA) zone size and estimate the volume of treated tissue for thyroid applications, a model was developed, taking into account dynamic optical and thermal properties of tissue change. For validation, ten Yorkshire swines were equally divided into two cohorts and underwent thyroid LA at 3 W/1,400 J and 3 W/1,800 J respectively with a 1064-nm multi-source laser (Echolaser X4 with Orblaze™ technology; ElEn SpA, Calenzano, Italy). The dataset was analyzed employing key statistical measures such as mean and standard deviation (SD). Model simulation data were compared with animal gross histology. Experimental data for longitudinal length, width (transverse length), ablation volume and sphericity were 11.0 mm, 10.0 mm, 0.6 mL and 0.91, respectively at 1,400 J and 14.6 mm, 12.4 mm, 1.12 mL and 0.83, respectively at 1,800 J. Gross histology data showed excellent reproducibility of the ablation zone among same laser settings; for both 1,400 J and 1,800 J, the SD of the in vivo parameters was ≤ 0.7 mm, except for width at 1,800 J, for which the SD was 1.1 mm. Simulated data for longitudinal length, width, ablation volume and sphericity were 11.6 mm, 10.0 mm, 0.62 mL and 0.88, respectively at 1,400 J and 14.2 mm, 12.0 mm, 1.06 mL and 0.84, respectively at 1,800 J. Experimental data for ablation volume, sphericity coefficient, and longitudinal and transverse lengths of thermal damaged area showed good agreement with the simulation data. Simulation datasets were successfully incorporated into proprietary planning software (Echolaser Smart Interface, Elesta SpA, Calenzano, Italy) to provide guidance for LA of papillary thyroid microcarcinomas. Our mathematical model showed good predictability of coagulative necrosis when compared with data from in vivo animal experiments.

Laser Ablation for Benign and Malignant Thyroid Nodules - A Mini-Literature Review

BACKGROUND

Thyroid nodules are a common disease in endocrine clinical practice. They are often benign, asymptomatic, and do not require any treatment. But, in a non-negligible proportion, they can cause local symptoms of compression or esthetic concerns. In the last two decades, the advent of laser ablation (LA) has become a valid alternative to surgery for these nodules. Moreover, LA has also been successfully used to treat small thyroid cancers and neck recurrence.

OBJECTIVE

This study aims to review and summarize the published literature regarding LA in the treatment of benign and malignant thyroid nodules.

METHODS

A comprehensive literature search on PubMed from 2000 to 2023 was carried out. The search terms included: thyroid, nodules, laser, cancer, lymph node metastasis, and autonomously functioning nodules. The most relevant investigations in the field were selected.

RESULTS

In the last two decades, a very remarkable number of papers consistently demonstrated that LA is able to durably shrink benign nodules on average by about 50%; better results are obtained in spongiform nodules with a volume less than 15 ml; 500 J/ml of tissue should be administered. LA may be a valid option to treat autonomously functioning nodules and papillary thyroid cancers especially if they are <10 mm, and with neck recurrence in patients already submitted to surgery. LA has also been demonstrated to be cost-effective compared to surgical treatment both in benign and malignant lesions, with similar outcomes.

CONCLUSION

Evidence demonstrated that LA is a valid alternative to surgery in benign and malignant thyroid lesions, but also to obtain a successful treatment, a careful selection of the lesion is mandatory.

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.

Global research landscape and trends of papillary thyroid cancer therapy: a bibliometric analysis

Background

Papillary thyroid cancer (PTC) is the most common endocrine malignancy worldwide. The treatment of PTC has attracted extensive attention and discussion from the public and scholars. However, no article has systematically assessed the related literature. Therefore, we conducted a bibliometric and knowledge map analysis to reveal the dynamic scientific developments in the PTC therapy field.

Methods

We retrieved publications related to PTC therapy from the Web of Scientific Core Collection (WoSCC) on May 1, 2023. The bibliometric package in R software, VOSviewer and CiteSpace software were used to analyze countries/regions, institutions, journals, authors, references, and keywords. Then, we systematized and summarized the research landscape, global trends and hot topics of research.

Results

This bibliometric analysis spanned from 2012 to 2022 and involved 18,501 authors affiliated with 3,426 institutions across 87 countries/regions, resulting in the publication of 3,954 papers in 860 academic journals. Notably, the number of publications and citations related to PTC therapy research has exhibited a steady increase over the past decade. China and the United States have emerged as leading contributors in terms of publication count, with the United States also being the most cited country. Furthermore, among the top 10 institutions with the highest number of published papers, half were located in China. Among the journals, Thyroid is ranked first in terms of total publications and citations. The most productive individual author was Miyauchi Akira. While previous research primarily focused on surgery and radioactive iodine therapy, the increasing emphasis on health awareness and advancements in medical technology have led to the emergence of active surveillance, thermal ablation, and genomic analysis as prominent areas of research.

Conclusion

In conclusion, this comprehensive and quantitative bibliometric analysis elucidates the research trends and hotspots within PTC therapy, drawing from a substantial body of publications. This study provides valuable insights into the historical and current landscape of PTC therapy research while also offering guidance for future research directions. This study serves as a valuable resource for researchers and practitioners seeking new avenues of exploration in the field.

[Application of Radiofrequency Ablation to Thyroid Cancer: Past, Present, and Future]

Thyroid cancer, characterized by high incidence rates, good prognosis, and frequent recurrence, is typically treated surgically. However, since the early 2000s, radiofrequency ablation, which is commonly utilized in liver, lung, and kidney cancers, is being performed for management of primary and recurrent thyroid cancers. Many studies have focused on inoperable cases of low-risk papillary microcarcinoma (≤ 1 cm) and some have investigated its role in larger lesions (up to 4 cm). Overall, these studies have reported positive results. Radiofrequency ablation for recurrent cancer has primarily been performed for locally recurrent cervical cancer, and this therapeutic approach has been attempted for treatment of distant metastases in lungs and bones, with encouraging outcomes. A growing global trend, particularly in South Korea, the United States, and Europe supports radiofrequency ablation for thyroid cancer. However, this therapy is currently not recognized as a treatment option recommended by universally accepted clinical guidelines such as those established by the National Comprehensive Cancer Network. Based on past efforts and future research, radiofrequency ablation is expected to play a key role in thyroid cancer treatment in the near future.

Efficacy and Safety of Different Thermal Ablation Modalities for Papillary Thyroid Microcarcinoma: A Network Meta-Analysis

Background

Small thyroid-like carcinoma (PTMC) is one of the most common subtypes of thyroid cancer. The main treatment options include surgery and radiofrequency ablation (RFA), microwave ablation (MWA), and laser ablation (LA). Thermal ablation has the advantage of being less invasive and has fewer complications than traditional surgical treatment.

Objective

The objective is to explore the efficacy and safety of PTMC by different thermal ablation modalities through a network meta-analysis.

Methods

From the database establishment to October 2021, a computerized search of the Chinese Knowledge Infrastructure (CKNI), VIP Chinese Science and Technology Journal Full-Text Database (VP-CSJFD), WanFang Data journal article resource (WangFang), PubMed, the Cochrane Library, and Embase were performed to include the different methods of thermal ablation for small thyroid carcinoma. A retrospective study of different methods of thermal ablation of small thyroid carcinoma was included.

Results

A total of 12 retrospective studies involving 1,926 patients with PTMC were included, all of which were of high quality. This study mainly involved RFA, MWA, LA, and ethanol combined with radiofrequency ablation (EA + RFA). Network meta-analysis showed no significant difference between interventions (p > 0.05) in terms of recurrence rate.

Conclusions

Surgical resection may be the measure with the lowest recurrence rate after treatment of PTMC, LA may be the measure with the lowest incidence of complications after treatment, and RFA may be the measure with the least length of hospital stay, operation time, and postoperative lymph node metastasis rate. However, due to the limitations of network meta-analysis, this result still needs to be treated with caution, and more high-quality, large-sample clinical studies are recommended for further verification.

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.

Thermal Ablation for the Management of Papillary Thyroid Microcarcinoma in the Era of Active Surveillance and Hemithyroidectomy

PURPOSE OF REVIEW

Thermal ablation presents a therapeutic option other than active surveillance and immediate surgery for patients with low-risk papillary thyroid microcarcinomas (PTMC). Here, we have reviewed the current oncologic outcome of thermal ablation in PTMC cases and compared it with active surveillance and surgery.

RECENT FINDINGS

Thermal ablation in PTMC cases revealed no tumor progression for pooled 5-year follow-up data. This oncologic outcome of thermal ablation was comparable to that of immediate surgery with less morbidity. Additionally, no patient who underwent thermal ablation received delayed surgery during the follow-up period due to anxiety. However, active surveillance has indicated that a substantial proportion (range, 8-32%) of patients underwent surgery mainly due to anxiety. In a subset of PTMC patients who are high-risk surgical candidates or who refuse surgery, especially those who have failed or are reluctant to pursue active surveillance, thermal ablation can be a good option.

Economic effect between surgery and thermal ablation for patients with papillary thyroid microcarcinoma: a systemic review and meta-analysis

BACKGROUND

At present, there are still many controversies regarding the treatment of papillary thyroid microcarcinoma (PTMC). It is worth noting that thermal ablation has become a viable alternative for patients at high risk of surgery or those who wish to receive more active treatment than active surveillance.

OBJECTIVE

To investigate the economic benefits, efficacy, and safety of thermal ablation for patients with PTMC.

METHODS

We searched PubMed, Cochrane Library, Web of Science, and Embase for articles published from the database establishment to August 2021. All of the studies included were retrospective cohort analyses. In addition, meta-analysis was performed using the Stata15.1 versions and Review Manager5.3. Data were extracted according to the PRISMA guidelines by two professional doctors.

RESULTS

A total of 7 articles (1582 patients) were included in our systematic review and meta-analysis. We discovered that thermal ablation could shorten the hospitalization time (SMD, -3.82[95%CI, -5.25 to -2.40]), operation time (SMD, -5.67[95%CI, -6.65 to -4.68]), cost (SMD, -3.40 [95%CI, -5.06 to -1.75]) and reduce postoperative complications (OR, 0.07 [95%CI, 0.01 to 0.44]) than surgical treatment. In addition, our study also found that compared with surgery, there was no significant difference in the recurrence rate (OR, 1.53 [95% CI, 0.63 to 3.73]) and metastasis rate (OR, 0.47 [95% CI, 0.12 to 1.86]).

CONCLUSION

On the premise of being safe and effective, thermal ablation has better economic benefits than surgical treatment for patients with PTMC.

Nomograms based on preoperative multimodal ultrasound of papillary thyroid carcinoma for predicting central lymph node metastasis

OBJECTIVES

To establish a nomogram for predicting central lymph node metastasis (CLNM) based on the preoperative clinical and multimodal ultrasound (US) features of papillary thyroid carcinoma (PTC) and cervical LNs.

METHODS

Overall, 822 patients with PTC were included in this retrospective study. A thyroid tumor ultrasound model (TTUM) and thyroid tumor and cervical LN ultrasound model (TTCLNUM) were constructed as nomograms to predict the CLNM risk. Areas under the curve (AUCs) evaluated model performance. Calibration and decision curves were applied to assess the accuracy and clinical utility.

RESULTS

For the TTUM training and test sets, the AUCs were 0.786 and 0.789 and bias-corrected AUCs were 0.786 and 0.831, respectively. For the TTCLNUM training and test sets, the AUCs were 0.806 and 0.804 and bias-corrected AUCs were 0.807 and 0.827, respectively. Calibration and decision curves for the TTCLNUM nomogram exhibited higher accuracy and clinical practicability. The AUCs were 0.746 and 0.719 and specificities were 0.942 and 0.905 for the training and test sets, respectively, when the US tumor size was ≤ 8.45 mm, while the AUCs were 0.737 and 0.824 and sensitivity were 0.905 and 0.880, respectively, when the US tumor size was > 8.45 mm.

CONCLUSION

The TTCLNUM nomogram exhibited better predictive performance, especially for the CLNM risk of different PTC tumor sizes. Thus, it serves as a useful clinical tool to supply valuable information for active surveillance and treatment decisions.

KEY POINTS

• Our preoperative noninvasive and intuitive prediction method can improve the accuracy of central lymph node metastasis (CLNM) risk assessment and guide clinical treatment in line with current trends toward personalized treatments. • Preoperative clinical and multimodal ultrasound features of primary papillary thyroid carcinoma (PTC) tumors and cervical LNs were directly used to build an accurate and easy-to-use nomogram for predicting CLNM. • The thyroid tumor and cervical lymph node ultrasound model exhibited better performance for predicting the CLNM of different PTC tumor sizes. It may serve as a useful clinical tool to provide valuable information for active surveillance and treatment decisions.

A Risk Stratification Model for Metastatic Lymph Nodes of Papillary Thyroid Cancer: A Retrospective Study Based on Sonographic Features

BACKGROUND

Papillary thyroid carcinoma (PTC) has a high probability of cervical lymph node (LN) metastasis. The aim of the study was to develop an ultrasound risk stratification model to standardize the diagnosis of metastatic LNs of PTC.

METHODS

Patients with suspicious thyroid nodules who underwent US examination and US guided fine-needle aspiration for cervical LNs were retrospectively collected. Univariate and multivariate logistic regression analyses were performed to assess the independent risk factor of metastatic LNs. According to the OR value of correlated indicators in logistic regression analysis, a risk stratification model was established.

RESULTS

A total of 653 LNs were included. The independent risk factors of metastatic LNs were long-axis diameter/short-axis ≤ 2 (OR=1.644), absence of hilum (OR=1.894), hyperechogenicity (OR=5.375), calcifications (OR=6.201), cystic change (OR=71.818), and abnormal flow (OR=3.811) (P<0.05 for all). The risk stratification model and malignancy rate were as follows: 0-2 points, malignancy rate of 10.61%, low suspicion; 3-5 points, malignancy rate of 50.49%, intermediate suspicion, ≥6 points, malignancy rate of 84.81%, high suspicion. The area under the receiver operating characteristic curve for the model was 0.827 (95% CI 0.795-0.859).

CONCLUSIONS

Our established risk stratification model can effectively evaluate metastatic LNs in the patients with suspicious thyroid nodules, and it might provide a new strategy choice for clinical practice.

Safety and efficacy of thermal ablation for cervical metastatic lymph nodes in papillary thyroid carcinoma: A systematic review and meta-analysis

BACKGROUND

To evaluate the safety and efficacy of radiofrequency ablation (RFA), microwave ablation (MWA), and laser ablation (LA) for the treatment of cervical metastatic lymph nodes (CMLNs) of papillary thyroid carcinoma (PTC).

METHODS

The Pubmed, EMBASE, Web of Science, and Cochrane Library databases were searched for studies on the safety and efficacy of thermal ablations (RFA, MWA, and LA) for the treatment of CMLNs of PTC until March 30, 2022. A review of 334 potential papers identified 17 eligible papers including 312 patients. Fixed-effects model or random-effects model was used to evaluate the pooled proportions of volume reduction rate (VRR), complete disappearance, and recurrence, and pooled estimates of changes in the largest diameter, volume, and serum Tg after ablation. The pooled proportions of overall and major complications were calculated. Subgroup analysis based on treatment modalities. The heterogeneity among studies was analyzed by using Q statistics and inconsistency index I² . MINORS scale was used to evaluate the quality of the studies.

RESULTS

17 eligible studies were finally identified, including 312 patients and 559 CMLNs. The pooled proportions of VRR, complete disappearance and recurrence of CMLNs were 91.28% [95% confidence interval (CI): 86.60-95.97%], 67.9% [95% CI: 53.1-81.1%] and 7.8% [95%CI: 3.0-14.1%], respectively. The pooled estimates of changes in the largest diameter, volume and serum Tg were 8.12 mm [95%CI: 6.78-9.46 mm], 338.75 mm³ [95%CI: 206.85 -470.65 mm³] and 5.96 ng/ml [95%CI: 3.68-8.24 ng/ml], respectively. The pooled proportions of overall and major complications were 2.9% [95%CI: 0.3-7.1%] and 0.3% [95%CI: 0-1.9%], respectively. Significant between-study heterogeneity was observed for complete disappearance (P<0.01, I² =88.6%), VRR (P<0.001, I² =99.9%), recurrence (P=0.02, I² =47.76%), overall complications (P<0.02, I² =44.8%), and changes in the largest diameter (P < 0.001, I² =82.6%), volume (P<0.001, I² =97.0%), and serum Tg (P < 0.001, I² =93.7%). Subgroup analysis showed heterogeneity of the VRR among the treatment modality (I² range: 84.4-100%). The VRR of MWA was the highest (97.97%), followed by RFA (95.57%) and LA (84.46%) (P < 0.001).

CONCLUSION

All thermal ablations were safe and effective for the treatment of CMLNs of PTC. However, each treatment had significant heterogeneity in VRR. Compared with RFA and MWA, LA was less effective in reducing the volume of CMLNs of PTC.

2022 Expert consensus on the use of laser ablation for papillary thyroid microcarcinoma

OBJECTIVE

With the aim of standardizing and improving the use of ultrasound-guided PLA on PTMC, a panel of experts from China and Italy, jointly issued this expert consensus on the clinical use of PLA for low-risk PTMC.

METHODS

This expert consensus was developed by Chinese and Italian experts who have specific competence and expertise in this area. An evidence-based approach combining the knowledge and practical experience of the panelists was utilized.

RESULTS

Twenty-six expert consensus recommendations were developed, spanning topics including the indications and contraindications of PLA for PTMC, physician training, preoperative preparation of patients, intraoperative technical procedures, possible complications, efficacy assessment, follow-up strategy, the approach to new PTMC and metastatic lymph nodes after treatment, thyroid-stimulating hormone inhibition therapy, and quality control of the entire procedure.

CONCLUSION

We summarized practical recommendations about standardized and improved PLA treatment for PTMC.

The value of ultrasound guided laser ablation in papillary thyroid recurrence carcinoma: A retrospective, single center study from China

OBJECTIVE

The efficacy and safety of ultrasound-guided percutaneous laser ablation (PLA) for treating recurrent papillary thyroid cancer nodules (RPTCNs).

METHODS

A retrospective study was conducted in 43 patients with single recurrent thyroid cancer which was diagnosed by fine needle aspiration biopsy (FNAB). The extent of ablation was assessed by contrast-enhanced ultrasound (CEUS) 24h after PLA. At baseline (before ablation), 6, and 12 months, and every 6 months thereafter, the following were recorded: nodule maximum diameter, volume reduction rate (VRR), complications, and side effects.

RESULT

All 43 patients were successfully treated with PLA without serious complications. All patients underwent CEUS 24 hours after PLA treatment, and all achieved complete ablation. The success rate of single ablation was 100%. The average follow-up time was 23.47 ± 6.50 months, 12 ~ 36 months. At the last follow-up, 32 (74.4%) ablation lesions disappeared completely and 11 (25.6%) ablation lesions showed scar-like changes. No lymph node metastasis was found during follow-up. The maximum diameter and volume of nodules decreased from 5.1 ± 1.4 mm, 86.22 ± 20.46 mm³ before operation to 0.73 ± 1.1 mm, 1.02 ± 1.92 mm³ at the end of observation (P < 0.01). The average volume reduction rates (VRR) at 6, 12, 18, 24, 30 and 36 months after ablation were 11.92%, 60.64%, 82.26%, 90.96%, 93.7% and 97.79% respectively. No regrowth of treated nodule and distant metastases were detected. One patient (2.3%) had local recurrence and was treated with PLA again.

CONCLUSION

Ultrasound-guided PLA appears to be effective and safe for treating unifocal RPTCNs in selected patients who are ineligible for surgery, which is suitable for clinical application and promotion.

Safety and efficacy of ultrasound-guided thermal ablation in treating T1aN0M0 and T1bN0M0 papillary thyroid carcinoma: A meta-analysis

BACKGROUND

Papillary thyroid cancer (PTC) is the most common thyroid tumor, and early diagnosis and treatment can effectively improve prognosis. Many controversies surround the treatment method of T1N0M0 PTC. Recently, thermal ablation (TA) has shown some benefits in the treatment of PTC patients, but the safety and efficacy of its treatment remain controversial. This article performs a meta-analysis of TA in patients with T1aN0M0 and T1bN0M0 PTC.

METHODS

The PubMed, Embase, Web of Science, and Cochrane Library databases were systematically searched for retrospective or prospective studies of TA for treating patients with T1N0M0 PTC from the database establishment to May 1, 2022. Data on volume reduction rate (VRR), disease progress, and complication rate were collected. In addition, a meta-analysis was performed using the Stata 12.0 and Review Manager 5.3.

RESULTS

A total of 9 eligible studies were included. Our study demonstrated the effectiveness of VRR and disease progress. The VRR was reduced after 3 months (-75.90%; 95% CI [-118.46-33.34%]), 6 months (34.33%; 95% CI [15.01-53.65%]), 12 months (78.69%; 95% CI [71.69-85.68%]), and 24 months (89.97%; 95% CI [84.00-95.94%]). The disease progress was 1.9% (95% CI [1.1-3.0]). Safety is justified by the complication rate, which was 6.5% (95% CI [3.5-10.2]). Pain and hoarseness were the most common complications, and no life-threatening complications were reported. Egger's test demonstrated that publication bias was acceptable.

CONCLUSIONS

TA is an effective and safe method for managing T1aN0M0 and T1bN0M0 papillary thyroid nodules.

The feasibility and efficacy of ultrasound-guided percutaneous laser ablation for multifocal papillary thyroid microcarcinoma

OBJECTIVE

The aim of this study was to evaluate the feasibility and efficacy of percutaneous laser ablation (PLA) for patients with multifocal papillary thyroid microcarcinoma (PTMC).

MATERIALS AND METHODS

A cohort of patients who underwent ultrasound (US)-guided PLA for primary PTMC were enrolled in this study. The patients were divided into a multifocal PTMC (multi-PTMC) group and a unifocal PTMC (uni-PTMC) group. Before PLA, conventional US and contrast-enhanced ultrasound (CEUS) were performed to evaluate the PTMC and cervical lymph nodes. The operation time, energy, power, amount of isolation liquid, and complications during PLA were recorded. Patients were followed up at 2 days, 1 month, 3 months, and 6 months, and every 6 months after that. Volume reduction rate (VRR), local tumor recurrence, and lymph node metastasis after PLA were observed.

RESULTS

The study included 12 patients with 26 PTMCs and 60 patients with 60 PTMCs. The operation time, total energy, and amount of isolation liquid in the multi-PTMC group were more than those in the uni-PTMC group (p = 0.000, 0.007, and 0.020, respectively). The mean follow-up durations in multi-PTMC and uni-PTMC groups were 19.75 ± 11.46 months (6-36 months) and 16.33 ± 10.01 months (4-40 months), with a similar VRR of the ablated lesions in the two groups. One and three cases with newly developed PTMCs were observed in the multi-PTMC group and the uni-PTMC group during follow-up, respectively. There was no regrowth of treated lesions, lymph node metastasis, or distant metastasis. At the end of the follow-up, all the ablated lesions in the two groups completely disappeared or only remained scar strips.

CONCLUSION

PLA is a safe and effective technique for treating multifocal PTMC, which might be an alternative technique for patients who are not eligible or are unwilling to undergo surgery.

Long-Term Follow-Up of Single-Fiber Multiple Low-Intensity Energy Laser Ablation Technique of Benign Thyroid Nodules

Aim

The short-term and long-term efficacy of different thermal percutaneous ablation techniques remains a topical issue. Our group implemented percutaneous laser ablation (LA), a moving-shot technique to increase efficiency and reduce costs and variability of LA by applying multiple lower-intensity energy illuminations (MLIEI) covering the nodular volume (V) through changes in position of a single laser fiber within the thyroid nodule. The aim of the present study was to evaluate the efficacy of the single-fiber LA-MLIEI during a 5-year follow-up and to identify possible predictors of the final outcome.

Methods

Prospective study: Thirty outpatients (23 women and seven men) with benign symptomatic thyroid nodules were assigned to single-fiber LA-MLIEI, between 2012 and 2015. A single LA session was performed under real-time ultrasound (US) guidance using a 1,064-nm continuous-wave laser at 3 W. A 400-µm optical fiber was inserted through a 21-gauge needle, and 3–10 illuminations were performed per nodule, administering between 400 and 850 J/illumination. The total administered energy was calculated on the initial V of the nodule and the estimated ablation area. US evaluation was performed after LA-MLIEI at 1 week and 1, 3, 6, and 12 months and after that annually up to 5 years. Clinical symptoms, laboratory thyroid function during follow-up, and acute and chronic complications of treatment were registered.

Results

On follow-up, 67% (n: 20) were responders to single-fiber LA-MLIEI, while 33% (n: 10) were non-responders. The responder group initiated V reduction (ΔV) at 1 month, with remission of symptoms, and presented a 50% ΔV at 3 months of treatment; the maximum response was achieved at 24 months and remained stable until the end of the study. The non-responder group presented a ΔV of less than 50% at 12 months; though a tendency to >50% ΔV was observed at 24–36 months, there was subsequent regrowth, and 40% of this group required surgery. ΔV was positively correlated with the total administered energy/V (J/V) and inversely with nodule V. No severe adverse effects were observed. Thyroid function remained normal in all patients. Remission of symptoms occurred rapidly after 1 month.

Conclusions

LA with multiple fractional discharges employing a single fiber in a unique session is a safe and inexpensive technique that allows rapid reduction of thyroid nodules, with a stable response up to 5 years, similarly to what has been reported with the conventional LA. Total nodule volume appears as a predictive factor of the reduction.

Radiofrequency ablation of recurrent thyroid cancers: anatomy-based management

Although differentiated thyroid cancer has an excellent prognosis and low mortality, its recurrence rate has been reported to be very high. While surgery is recommended as the standard treatment for recurrent thyroid cancer, reoperation may increase the incidence of complications due to fibrosis and anatomical distortion. In patients with high surgical risk or those who refuse repeated surgery, ultrasonography-guided ablation techniques including radiofrequency ablation, ethanol ablation, and laser ablation are suggested as alternative treatments. In this manuscript, we introduce an anatomy-based management concept for radiofrequency ablation for recurrent thyroid cancer, and present a review of the relevant literature, including indications, basic techniques, clinical outcomes, and complications.

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.

A cohort study of microwave ablation and surgery for low-risk papillary thyroid microcarcinoma

BACKGROUND

The optimal treatment method for papillary thyroid microcarcinoma (PTMC) is lacking consensus. Here we aimed to compare the efficacy and safety of surgery and microwave ablation (MWA) for PTMC.

METHODS

The clinical data of 644 patients with PTMC treated between July 2013 and June 2020 were retrospectively analyzed. A total of 320 and 324 patients underwent MWA and surgery, respectively. We observed lesion changes in the MWA group and compared the recurrence, metastasis, complications, and other health economic indicators between the 2 groups.

RESULTS

The mean follow-up time was 890.7 ± 532.9 (187.9-2679.0) days in the MWA group and 910.9 ± 568.4 (193.8-2821.5) days in the surgery group. In the MWA group, lesion volume increased significantly after ablation and then gradually decreased. The final lesion volume reduction rate was 90.73% ± 7.94%, and 193 lesions (60.3%) disappeared completely. There were no significant intergroup differences in recurrence or metastasis. The incidence of main complications (temporary hypothyroidism, hypoparathyroidism, and temporary hoarseness) was significantly lower in the MWA group than in the surgery group (p < 0.001). The treatment time, intraoperative blood loss, and hospital stay were significantly lower in the MWA group than in the surgery group (p < 0.001).

CONCLUSIONS

MWA is effective for treating PTMC, with a low incidence of complications and less trauma. The rates of post-treatment recurrence and metastasis are similar to those of surgery, indicating that MWA is a suitable alternative to surgery.

Ultrasound-Guided Percutaneous Laser Ablation of the Thyroid Gland in a Swine Model: Comparison of Ablation Parameters and Ablation Zone Dimensions

BACKGROUND

To compare laser ablation (LA) zone dimensions at two predetermined energy parameters to cover a theoretical 10 mm zone + 2 mm margin in a thyroid swine model.

METHODS

Approval of the Institutional Animal Care and Use Committee was obtained. After hydrodissection, an ultrasound-guided LA (Elesta Echolaser X4 with Orblaze technology, 1064 nm) was performed in the periphery of the thyroid in 10 swine. Two cohorts were established to ablate a region of 10mm diameter with 2mm margin based on manufacturer's ex vivo data (n= 5 at 3W/1400J and n= 5 at 3W/1800J). The ablation zone was measured on contrast-enhanced computed tomography (CT) and compared to the pathological specimen. Euthanasia was performed 48 hours following ablation.

RESULTS

All ablations in the 3W/1800J group achieved a diameter of 12 mm ± 1 mm in three dimensions. In the 3W/1400J group, 1 ablation reached 12 mm ± 1 mm in 2 dimensions and 4 ablations reached this size in one dimension. Maximum diameter was higher in the 3W/1800J compared to the 3W/1400J group, both on histology (1.46 cm ± 0.05 vs. 1.1 cm ± 0.0, p< 0.01) and CT (1.52 cm ± 0.04 vs. 1.18 cm ± 0.04, p< 0.01). Similar results were obtained regarding volumes, both on histology (1.12 mL ± 0.13 vs. 0.57 mL ± 0.06, p< 0.01) and CT (1.24 mL ± 0.13 vs. 0.59 mL ± 0.07, p< 0.01). Histology showed coagulation necrosis and correlated well with CT measurements.

CONCLUSION

Optimal parameters to obtain a LA zone of 10 mm with 2 mm margin utilizing a single needle are 3W/1800J.

Ultrasound-Guided Radiofrequency Ablation Versus Thyroid Lobectomy for Low-Risk Papillary Thyroid Microcarcinoma: A Propensity-Matched Cohort Study of 884 Patients

Background: Thermal ablation (TA) has been applied in patients with low-risk papillary thyroid microcarcinoma (PTMC) who refuse surgery or active surveillance (AS). Recently, TA has been proposed as a potential therapeutic option for patients who are suitable for surgery or AS. However, the clinical outcomes of TA versus surgery remains controversial because of a lack of sufficient data. This study aimed to compare the clinical outcomes between radiofrequency ablation (RFA) versus thyroid lobectomy (TL) for low-risk PTMC in a large cohort. Methods: This retrospective study evaluated 884 patients with unifocal low-risk PTMC treated with TL or RFA from June 2014 to March 2018. Among them, 460 patients underwent TL (TL group) and 424 patients, who refused surgery or AS, underwent RFA (RFA group). Patients were regularly followed up after treatment. Local tumor progression, recurrence-free survival (RFS), complications, and treatment variables, including procedure time, estimated blood loss, hospitalization, and cost, were compared after propensity score matching (PSM). Results: After PSM, a total of 332 patients underwent TL (mean ages 43.8 ± 9.5 years) and 332 underwent RFA (mean ages 44.1 ± 9.5 years). During the follow-up (median [interquartile ranges], 48.3 [23.2] months), no significant differences were observed in local tumor progression (1.8% vs. 3.3%, p = 0.209), lymph node metastasis (0.6% vs. 0.6%, p = 1.000), recurrent PTMC (1.2% vs. 2.4%, p = 0.244), persistent lesion (0% vs. 0.3%, p = 0.317), and 4-year RFS rates (98.2% vs. 97.0%, p = 0.223) between the TL and RFA groups. Distant metastasis was not detected. None of the patients who were treated by RFA underwent delayed surgery. Patients undergoing RFA had shorter procedure time (3.4 [2.5] vs. 86.0 [37.0] minutes, p < 0.001), lower estimated blood loss (0 vs. 20 [10.0] mL, p < 0.001), shorter hospitalization (0 vs. 7.0 [3.0] days, p < 0.001), lower cost ($2035.7 [254.0] vs. $2269.1 [943.4], p < 0.001) and lower complication rate (0% vs. 4.5%, p < 0.001) than those treated by TL. The association between treatment modality and recurrence remained nonsignificant after Cox analysis (p = 0.247). Conclusions: This large matched study revealed comparable four-year clinical outcomes between RFA and TL for low-risk PTMC. As a minimally invasive modality, RFA may be a promising alternative to the existing treatment options for low-risk PTMC.

Long-Term Efficacy of Ultrasound-Guided Laser Ablation for Papillary Thyroid Microcarcinoma: Results of a 10-Year Retrospective Study

Background: The aim of this study was to evaluate the 10-year efficacy and safety of laser ablation (LA) for the treatment of solitary papillary thyroid microcarcinoma (PTMC). Methods: LA was performed on patients with low-risk PTMC (diagnosed using fine-needle aspiration cytology) who refused or were ineligible for surgery between 2008 and 2011. Ultrasonography was performed to evaluate the ablated volumes and potential recurrences on the day after the procedure, as well as at 1 week, 1, 3, and 6 months, and every 6 months thereafter for 10 years. Computed tomography (CT) with contrast enhancement and positron emission tomography/CT was performed to evaluate local recurrences and distant metastases. Results: A total of 90 PTMCs in 90 patients were treated in a single session of LA, and the procedure was well tolerated by the patients. The mean follow-up duration was 112 months. By 3-10 months after the LA, all the ablation areas had disappeared or presented as scars. The disappearance rate was 100% after 12 months. Thyroid hormone and autoantibody levels did not change significantly after the treatment. Three patients experienced transient voice changes, but each recovered within 1 month. Additional PTMC foci were subsequently detected in previously untreated areas in five patients (5.5%) 17-56 months after the treatment. A metastatic lymph node was detected in one patient (1.1%) within two months of the treatment; however, it was determined to be an undetected cancer metastasis, rather than a recurrence. All the patients with recurrence underwent surgery, and there were no instances of recurrence after >5 years. Conclusions: LA is effective and safe for the treatment of low-risk PTMCs. A thorough examination of multifocality and lymph node metastasis status is required before considering LA treatment.

Clinical outcomes of radiofrequency ablation for multifocal papillary thyroid microcarcinoma versus unifocal papillary thyroid microcarcinoma: a propensity-matched cohort study

OBJECTIVE

To investigate and compare the clinical outcomes of radiofrequency ablation (RFA) for multifocal papillary thyroid microcarcinoma (PTMC) versus unifocal PTMC in a large cohort.

METHODS

Patients with low-risk PTMC (n = 487) who underwent RFA were included in this retrospective study and divided into the unifocal group (U group) (n = 432) and the multifocal group (M group) (n = 55) according to the number of lesions. After 1:1 propensity score matching (PSM), volume, volume reduction ratio (VRR), the development of local tumor progression including lymph node metastasis (LNM), recurrent PTMC and persistent lesions, and recurrence-free survival (RFS) rate were evaluated and compared between the two groups. The different impacts of multifocality on recurrence after RFA for PTMC were investigated by Cox analysis.

RESULTS

During a mean follow-up time of 49.25 ± 12.98 months, the overall VRR was 99.40 ± 4.43% and the overall incidence of local tumor progression was 3.70% (18/487). No complications occurred after RFA. After PSM, no significant differences were found in volume (0.11 ± 0.69 mm³ vs 0 mm³, p = 0.441), VRR (99.87 ± 0.78% vs 100%, p = 0.441), complete disappearance rate (95.61% vs 89.09%, p = 0.201), incidence of local tumor progression (5.45% vs 5.45%, p = 1.000), LNM (1.82% vs 0%, p = 0.317), recurrent PTMC (1.82% vs 5.45%, p = 0.611), persistent lesions (1.82% vs 0%, p = 0.317), and RFS rate (96.36% vs 94.55%, p = 0.632) between the M group and U group. The association between multifocality and local tumor recurrence also remained nonsignificant (p = 0.619). No distant metastasis or delayed surgery occurred.

CONCLUSIONS

The impact of multifocality on the prognosis after RFA for low-risk PTMC was little. RFA might be a promising treatment for both unifocal and multifocal PTMC in properly selected patients after sufficient preoperative evaluation.

KEY POINTS

• No significant differences are found in the local tumor progression between the unifocal PTMC and multifocal PTMC. • Multifocality is not associated with higher recurrence after RFA for low-risk PTMC. • RFA is a promising alternative for both unifocal and multifocal PTMC.

Long-Term Efficacy of Ultrasound-Guided Percutaneous Laser Ablation for Low-Risk Papillary Thyroid Microcarcinoma: A 5-Year Follow-Up Study

Objective

To evaluate the long-term efficacy and safety of ultrasound-guided percutaneous laser ablation (PLA) for the treatment of low-risk papillary thyroid microcarcinoma (PTMC).

Methods

From June 2012 to May 2015, 105 patients with solitary, pathologically confirmed PTMC lesions were treated with ultrasound-guided PLA. Nodule location, nodule volume, thyroid function, and clinical symptoms were evaluated before ablation. Contrast-enhanced ultrasound (CEUS) was performed 1 h after treatment to evaluate whether the ablation was complete. Ultrasound examination was performed at 1, 3, 6, and 12 months after ablation and every 6 months thereafter to determine the size of the ablation area and search for recurrence in the thyroid parenchyma and lymph node metastasis. Thyroid function was examined before and 1 month after ablation. Fine needle aspiration biopsy was performed for any suspicious metastatic lymph nodes and recurrent lesions in the thyroid.

Results

All 105 lesions were completely inactivated after one ablation, making the success rate for single ablation 100%. The average ablation time was 2.78 ± 1.05 min, and the average ablation energy was 505 ± 185 J. All patients could tolerate and complete the ablation. No serious complications occurred during the treatment; only minor side effects such as pain and local discomfort were reported. The volume reduction rates were −781.14 ± 653.29% at 1 h posttreatment and −268.65 ± 179.57%, −98.39 ± 76.58%, 36.78 ± 30.32%, 75.55 ± 21.81%, 96.79 ± 10.57%, and 100% at 1, 3, 6, 12, 18, and 24 months after ablation, respectively. This rate remained 100% at the later follow-up times. Overall, 28 (26.67%), 74 (70.48%), 96 (91.43%), and 103 (100%) were completely absorbed by 6, 12, 18, and 24 months after PLA. One patient developed another lesion 12 months after ablation, and two patients had central cervical lymph node metastasis 24 months after ablation.

Conclusion

PLA is a safe and effective alternative clinical treatment for low-risk PTMC.

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.

Five-year follow-up results of thermal ablation for low-risk papillary thyroid microcarcinomas: systematic review and meta-analysis

OBJECTIVES

Confidence in long-term treatment results of thermal ablation for papillary thyroid microcarcinoma (PTMC) is required in comparison with active surveillance. The objective of this meta-analysis is to report 5-year follow-up results of thermal ablation for PTMC.

METHODS

Ovid MEDLINE and EMBASE databases were searched through May 30, 2020, for studies reporting outcomes in patients with PTMC treated with thermal ablation and followed up for at least 5 years. Data were extracted and methodological quality was assessed independently by two radiologists according to the PRISMA guidelines.

RESULTS

Three studies, involving 207 patients with 219 PTMCs, met the inclusion criteria through database searches. None of these patients experienced local tumor recurrence, lymph node metastasis, or distant metastasis or underwent delayed surgery during a mean pooled 67.8-month follow-up. Five new tumors appeared in the remaining thyroid gland of four patients, with four of these tumors successfully treated by repeat thermal ablation. The pooled mean major complication rate was 1.2%, with no patient experiencing life-threatening or delayed complications.

CONCLUSIONS

Thermal ablation is an excellent local tumor control method in patients with low-risk PTMC, with low major complication rates at 5 years.

KEY POINTS

• No local tumor recurrence, lymph node metastasis, or distant metastasis was noted by thermal ablation during follow-up of 5 years and none underwent delayed surgery. • The pooled mean major complication rate was 1.2%.

Residual tumor and central lymph node metastasis after thermal ablation of papillary thyroid carcinoma: A case report and review of literature

BACKGROUND

Debate exists regarding the use of thermal ablation (TA) to treat papillary thyroid carcinoma (PTC). Some studies have recommended TA as a new, efficient and safe technology for PTC. In this article, we report one case of a residual tumor and central lymph node metastasis (CLNM) after TA for PTC.

CASE SUMMARY

A 63-year-old female underwent bilateral ultrasound (US)-guided radiofrequency ablation for PTC. Three months later, she was diagnosed as thyroid cancer with suspected CLNM by US and contrast-enhanced computed tomography. The subsequent fine-needle aspiration (FNA) biopsies were negative. Due to her strong personal preference, she underwent total thyroidectomy and central lymph node dissection. Local tissue adhesion and a difficult dissection were noted during the operation. The pathology of the frozen sections during the operation was still negative. The final pathology results of paraffin-embedded sections revealed residual tumor cells at the edge of the PTC and CLNM.

CONCLUSION

TA may lead to a residual tumor in patients with PTC. Follow-up using US and FNA biopsy may not be adequate to evaluate the residual tumor. TA should be carefully considered in PTC treatment.

The Efficacy and Safety of Radiofrequency Ablation for Bilateral Papillary Thyroid Microcarcinoma

OBJECTIVE

To investigate the long-term clinical results of radiofrequency ablation (RFA) for bilateral papillary thyroid microcarcinoma (PTMC).

MATERIALS AND METHODS

From October 2014 to February 2018, 47 patients (37 females, 10 males, mean age 43.39 ± 9.26 years) with 100 bilateral PTMC (mean volume 75.22 ± 73.87 mm³) treated by RFA were included in this retrospective study. Bilateral PTMC was defined as at least one tumor located in the contralateral lobe. Patients were followed up at 1, 3, 6, 12 months and every 6-12 months thereafter. Volume, volume reduction ratio (VRR) and local tumor recurrence were evaluated during the follow-up period.

RESULTS

After a mean follow-up period of 47.77 ± 11.54 months, the mean volume of bilateral PTMC decreased from 75.22 ± 73.87 mm³ to 0.09 ± 0.44 mm³. The mean VRR was 99.94 ± 0.28% and the complete disappearance rate was 92.00%. During the follow-up, one patient (2.13%) developed lymph node metastasis and two patients (4.26%) had recurrent PTMC. All the recurrent lesions underwent additional RFA and two of them disappeared completely. No life-threatening or delayed complications occurred.

CONCLUSIONS

With sufficient preoperative evaluation, RFA might be a promising alternative for bilateral PTMC patients who were unsuitable for surgery or refused surgery.

Long-Term Follow-Up Results of Ultrasound-Guided Radiofrequency Ablation for Low-Risk Papillary Thyroid Microcarcinoma: More Than 5-Year Follow-Up for 84 Tumors

Background: Despite reports describing favorable short-term results for thermal ablation of thyroid cancer, there remains a need to evaluate long-term results because of its indolent characteristics. The purpose of this study was to evaluate the long-term efficacy and safety of ultrasound (US)-guided radiofrequency ablation (RFA) for low-risk papillary thyroid microcarcinoma (PTMC) over a follow-up period of more than five years. Methods: From a cohort of patients under surveillance after US-guided RFA for primary low-risk PTMC, those with a record of follow-up data of more than five years were selected for this study. Before RFA, all patients underwent US and computed tomography to evaluate the PTMC and the presence of neck metastasis. RFA was performed using thyroid-dedicated electrodes. Follow-up US was performed 6 and 12 months after initial RFA, and then every 12 months. The status of ablated tumors was evaluated according to volume reduction, local tumor progression, newly developed cancers, lymph node (LN) or distant metastasis, and delayed surgery during follow-up. Complications during the procedure and follow-up period were evaluated. Results: A total of 84 nodules from 74 patients were included in this study. All patients tolerated RFA, and the mean follow-up duration was 72 months. After RFA, complete disappearance rates of 98.8% and 100% were achieved at 24 and 60-month follow-up, respectively. Additional ablations were performed in 13 of 84 tumors. The mean number of RFA sessions was 1.2. There were four newly developed cancers in three patients, and these were also treated with RFA and completely disappeared. During the follow-up period, there was no local tumor progression, no LN or distant metastasis, and no patients underwent delayed surgery. The major complication rate was 1.4% (1/74), and there was no delayed complication or procedure-related death. Conclusions: RFA is effective for treating low-risk PTMC patients, without occurrence of local tumor progression, LN or distant metastasis, delayed complications, procedure-related death, or delayed surgery over more than five years of follow-up.

2020 Chinese guidelines for ultrasound malignancy risk stratification of thyroid nodules: the C-TIRADS

Thyroid nodules are very common all over the world, and China is no exception. Ultrasound plays an important role in determining the risk stratification of thyroid nodules, which is critical for clinical management of thyroid nodules. For the past few years, many versions of TIRADS (Thyroid Imaging Reporting and Data System) have been put forward by several institutions with the aim to identify whether nodules require fine-needle biopsy or ultrasound follow-up. However, no version of TIRADS has been widely adopted worldwide till date. In China, as many as ten versions of TIRADS have been used in different hospitals nationwide, causing a lot of confusion. With the support of the Superficial Organ and Vascular Ultrasound Group of the Society of Ultrasound in Medicine of the Chinese Medical Association, the Chinese-TIRADS that is in line with China's national conditions and medical status was established based on literature review, expert consensus, and multicenter data provided by the Chinese Artificial Intelligence Alliance for Thyroid and Breast Ultrasound.

Radiofrequency for benign and malign thyroid lesions

Background

Thermal ablation of thyroid nodules is new modality for the management of the benign and malign lesions. This minimally invasive treatment is performed as an outpatient, local anesthetic, single professional procedure that can treat neoplastic lesions without removing normal thyroid tissue and thus avoiding hypothyroidism.

Method

A comprehensive review of the most relevant literature regarding the thermal ablation of benign and malign nodules was performed in order to currently define its role on the management of the nodular thyroid disease. The data was divided into benign and malign literature.

Results

The benign nodules can be effectively treated by radiofrequency ablation (RFA) but some limitation exists regarding the nodule's size but not nodules characteristics. The RFA of primary malign tumors of the thyroid recently demonstrated positive and safe long-term follow-up and encouraged additional investigation and possibly a definitive role in the management of these low risk nodules.

Conclusion

RFA is a safe, cost-effective minimally invasive procedure that avoids thyroid tissue removal while destroying neoplastic one thus, preventing hypothyroidism.

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.

US-Guided Radiofrequency Ablation for Low-Risk Papillary Thyroid Microcarcinoma: Efficacy and Safety in a Large Population

OBJECTIVE

To evaluate the efficacy and safety of radiofrequency ablation (RFA) for low-risk papillary thyroid microcarcinoma (PTMC) in a large population.

MATERIALS AND METHODS

Cases of 152 biopsy-proven PTMCs from 133 patients who had undergone RFA for PTMC between May 2008 and January 2017 were included in this study. All patients were either of high surgical risk or refused to undergo surgery. They were followed up for at least 6 months after initial RFA. Ultrasonography (US) and computed tomography were performed to evaluate the PTMC and the presence of neck metastasis before treatment. RFA was conducted using an internally cooled thyroid-dedicated electrode system. Follow-up US was performed at 1 week, and 2, 6, and 12 months, after the initial RFA, and then at every 6-12 months. We evaluated serial changes of ablated tumors, newly developed cancers, lymph node (LN) or distant metastasis and complications.

RESULTS

Complete disappearance was found in 91.4% (139/152) of ablated tumors. Among the 13 tumors in patients who did not show complete disappearance, no tumor displayed any regrowth of the residual ablated lesion during the follow-up period. The mean follow-up period was 39 months. During the follow-up period, there were no local recurrence, no LN or distant metastasis, and no newly developed thyroid cancers. No patients were referred to surgery. The overall complication rate was 3% (4/133) of patients, including one voice change. There were no life-threatening complications or procedure-related deaths.

CONCLUSION

Our results suggest that RFA is an effective and safe option for treating low-risk PTMC patients who are of high surgical risk or refuse surgery.

The Clinical Application of Core-Needle Biopsy after Radiofrequency Ablation for Low-risk Papillary Thyroid Microcarcinoma: A Large Cohort of 202 Patients Study

Purpose: To evaluate the clinical application of core-needle biopsy (CNB) for low-risk papillary thyroid microcarcinoma (PTMC) after radiofrequency ablation (RFA) Methods: A total of 202 patients with 211 low-risk PTMCs were included in this study. RFA procedure was used the hydrodissection technique and moving-shot technique. Patients were followed at 1, 3, 6, 12 months and every 6 months thereafter. The volume of ablation area and the volume reduction ratio (VRR) were calculated. At 3 or 6 months after RFA, CNB was performed to the central zone, the peripheral zone and surrounding thyroid parenchyma for post-ablation evaluation. Results: The mean volume of tumors was 102.34±93.84 mm³ (range 4.19-424.10 mm³), which decreased significantly to 1.37±7.74 mm³ (range 0-73.30 mm³) at a mean follow-up time of 24.42±9.15 months (range 3-42 months) with a mean VRR of 99.14±4.18% (range 71.88-100%). A total of 3 ablation areas had positive CNB in the peripheral zone and underwent additional RFA. No recurrent or suspicious metastatic lymph nodes were detected Conclusion: CNB is a feasible and effective evaluation for low-risk PTMC after RFA, which can detect residual cancer cells early.

Safety and efficacy of ultrasound-guided percutaneous thermal ablation in treating low-risk papillary thyroid microcarcinoma: A pilot and feasibility study

Objective

This study aimed to evaluate the safety and efficacy of thermal ablation in treating low-risk unifocal papillary thyroid microcarcinoma (PTMC).

Materials and Methods

Patients with unifocal PTMC were enrolled in this study, and thermal ablations were performed. Contrast-enhanced ultrasound was used to estimate the extent of ablation immediately after thermal ablation; complications were recorded. The size and volume of the ablated area and thyroid hormones were measured, and the clinical evaluations were performed at 1, 3, 6, 12, and 18 months after thermal ablation. From July 2016 to July 2017, the prospective study was conducted involving 107 patients. Thermal ablation was well tolerated without serious complications.

Results

Compared with the volume immediately after thermal ablation, the mean volume reduction ratio (VRR) of ablated lesions was 0.457 ± 0.218 (range: 0.040-0.979), 0.837 ± 0.150 (range: 0.259-1), 0.943 ± 0.090 (range: 0.491-1), 0.994-0.012 (range: 0.938-1), and 0.999 ± 0.002 (range: 0.992-1) at 1, 3, 6, 12, and 18 months after thermal ablation, respectively. Significant differences in the VRR were found between every two follow-up visits (P < 0.01). Results of patients' thyroid function test before thermal ablation and at 1 month after thermal ablation were normal, and no significant differences were observed (P > 0.05). No tumor regrowth, local recurrence, or distant metastases were detected during follow-up visits.

Conclusion

Thermal ablation is a short-term safe and effective method in treating low-risk small PTMCs, which can be considered a potential alternative therapy for patients with PTMC.

Laser and radiofrequency ablations for benign and malignant thyroid tumors

A growing body of evidence is being published regarding the safety and efficacy of minimally invasive image-guided ablation techniques. While clinical applications of these techniques are increasing, international societies have started to publish treatment guidelines and to make efforts to standardize both terminology and reporting criteria for image-guided thyroid ablations. Laser ablation and radiofrequency ablation (RFA) are among the most common ablation techniques either for benign and malignant thyroid nodules. Unlike laser ablation and RFA in the treatment of benign thyroid nodules, where safety and efficacy have been widely demonstrated, evidence regarding local tumor control of thyroid malignancies is still limited. However, preliminary results are encouraging and image-guided thermal ablation techniques can be considered a valid alternative to surgery for the treatment of benign thyroid nodules and recurrent thyroid cancers. This review evaluates the basic concept of RFA and laser ablations, their techniques, clinical outcomes, and complications based on the suggestions of several society guidelines. Multidisciplinary collaboration remains critical to identify patients which may benefit from minimally invasive image-guided thermal ablations, especially if surgery or radioiodine therapy are not feasible options.

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.

Efficacy and safety of radiofrequency, microwave and laser ablation for treating papillary thyroid microcarcinoma: a systematic review and meta-analysis

Background: To evaluate the efficacy and safety of radiofrequency ablation (RFA), microwave ablation (MWA) and laser ablation (LA) for treating papillary thyroid microcarcinoma (PTMC).Materials and methods: PUBMED and EMBASE were searched for studies on the efficacy and safety of RFA, MWA and LA for treating PTMC. The standard mean difference of the tumor volume before and after therapy and the proportion of complete disappearance, local recurrence, distant metastasis and complications were assessed using both fixed or random-effects modeling. Heterogeneity among studies was determined using the Q statistic for the pooled estimates and the inconsistency index I².Results: A total of 12 eligible studies, including a sample size of 1187 patients and 1284 PTMCs, were used. RFA, MWA and LA all showed a significant reduction in tumor volume of PTMCs (p < 0.05). Though MWA demonstrated superior efficacy over the other two therapies for volume reduction, the differences were not statistically significant. Additionally, the pooled proportion of complete disappearance after RFA was the highest (76.2%), and the pooled proportion of recurrence for RFA was the lowest (0.01%) among the three therapeutic methods, but no significant difference was detected. There was no event of distant metastasis during the follow-up in all of these studies. Few major complications were encountered; the pooled proportion of complications for RFA (1.73%), MWA (6.0%) and LA (0.92%) was low, revealing no significant differences (p > 0.05).Conclusion: RFA, MWA and LA are acceptable treatments to manage PTMCs in terms of efficacy and safety for non-surgical candidates.

Ultrasound-Guided Laser Ablation Versus Microwave Ablation for Patients With Unifocal Papillary Thyroid Microcarcinoma: A Retrospective Study

BACKGROUND AND OBJECTIVES

The objective of this study is to compare the efficacy and the safety of ultrasound-guided microwave ablation (MWA) and laser ablation (LA) for the treatment of papillary thyroid microcarcinoma (PTMC).

STUDY DESIGN/MATERIALS AND METHODS

A total of 67 patients with unifocal PTMC were studied retrospectively, including 33 cases who underwent MWA (MWA group) and 34 cases who received LA (LA group). The follow-up consisted of thyroid function tests, ultrasonography, contrast-enhanced ultrasonography (CEUS), and chest X-ray or computed tomography scan. The treatment response and complications were compared between the two groups.

RESULTS

The follow-up time for the MWA and LA group was 23.3 ± 4.4 and 22.8 ± 4.1 months, respectively. All the ablations were successfully performed as planned without complementary ablations, and it was confirmed by CEUS after treatment in both groups. It was observed that, at the last follow-up, the mean largest diameter decreased from 5.0 ± 1.4 mm to 0.1 ± 0.4 mm (MWA group) and from 4.5 ± 1.6 mm to 0.6 ± 1.2 mm(LA group) (P < 0.05 for both). The average volume reduced from 51.9 ± 40.8 to 0.2 ± 1.0 mm³ (MWA group) and from 38.5 ± 43.0 to 1.3 ± 3.8 mm³ (LA group) (P < 0.05 for both). The complication rates did not differ between the MWA group (9.1%) and the LA group (2.9%) (P > 0.05). No local recurrence or distant metastasis occurred in either group.

CONCLUSIONS

During the short-term follow-up period, ultrasound-guided MWA and LA were both safe and effective methods in treating patients with unifocal PTMC. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.

Ultrasound-guided laser ablation versus surgery for solitary papillary thyroid microcarcinoma: a retrospective study

Objectives: To compare the clinical outcomes of ultrasound-guided laser ablation (LA) and surgery for treatment of solitary papillary thyroid microcarcinoma (PTMC). Methods: A total of 81 consecutive patients with solitary PTMC were included in this retrospective study. Among them, 36 received LA and 45 underwent surgery. Surgery was performed by hemithyroidectomy with unilateral central neck dissection. The follow-up consisted of a physical examination, neck ultrasonography, chest X-ray or CT scan and thyroid function tests. The procedure time, hospital stay, complication and recurrence rates were compared between the two groups after treatment. Results: The follow-up period for the LA and surgical group were 49.2 ± 4.5 months (range, 30-54 months) and 48.5 ± 6.2 months (range, 24-54 months), respectively. The mean hospital stay and procedure time in the LA group were shorter than those in the surgical group. After LA, the largest diameter and average volume decreased from 4.7 ± 1.4 mm to 0.2 ± 0.8 mm, and from 43.2 ± 38.8 mm³ to 0.7 ± 4.1 mm³ (p < .05 for both), respectively. The complication rates and recurrence rates did not differ between the LA group (2.8% [1 of 36] and 5.6% [2 of 36]) and the surgical group (6.7% [3 of 45] and 6.7% [3 of 45]) (p > .05 for both). No distant metastasis occurred in the either group during the follow-up period. Conclusions: Compared with hemithyroidectomy with unilateral central neck dissection, ultrasound-guided LA was also a safe and effective therapy for treating solitary PTMC, and it may be considered as a treatment alternative for patients who are ineligible or refusal to undergo surgery.

A comparative study of short-term efficacy and safety for thyroid micropapillary carcinoma patients after microwave ablation or surgery

Background: Although papillary thyroid microcarcinoma (PTMC) has a high incidence and excellent clinical outcome, debate continues as to the therapeutic approach that would be most appropriate after confirming the diagnosis. Methods: We retrospectively analyzed the medical records of 311 patients with T1aN0M0 PTMC between January 2013 and September 2018. In all, 168 underwent microwave ablation (MWA), and 143 underwent surgery. MWA was performed using extensive ablation with hydrodissection. The surgery comprised thyroid lobectomy (TL) with unilateral central lymph node dissection (CND). We examined clinical outcomes during mean follow-up periods of 824 ± 452 days for the TL group and 753 ± 520 days for the MWA group. Results: Postprocedural follow-up revealed that, in the MWA group, the tumors had completely disappeared in 34 patients, and the remainder were reduced to necrotic or carbonized tissue. The incidence of transient hypoparathyroidism was significantly lower in the MWA group than in the TL group (p < .001). In addition, during the follow-up, we found no statistically significant differences between the two groups (TL vs MWA) for PTMC recurrence (1 vs 2 cases), lymph node metastasis (5 vs 5 cases), or disease-free survival [2001 days (5.5 years) vs 1702 days (4.7 years)] (p = .659, p = .795, and p = .974, respectively). Conclusions: If low-risk thyroid carcinoma (i.e., T1N0M0 PTMC) is accurately diagnosed early, MWA could be a minimally invasive alternative to surgery based on our short-term follow-up regarding recurrence and the low rates of complications and disease-free survival.

Image-Guided Thermal Ablation as an Alternative to Surgery for Papillary Thyroid Microcarcinoma: Preliminary Results of an Italian Experience

PURPOSE

To report the results of our preliminary experience in treating patients with papillary thyroid microcarcinoma (PTMC) with image-guided thermal ablation, in particular estimating the feasibility, safety and short-term efficacy.

MATERIALS AND METHODS

From 2018 patients with cytologically proven PTMC < 10 mm were discussed in a multidisciplinary team and evaluated for feasibility of image-guided thermal ablation. In case of technical feasibility, the three possible alternatives (i.e., image-guided thermal ablation, surgery, and active surveillance) were discussed with patients. Patients who agreed to be treated with image guided thermal ablation underwent radiofrequency (RFA) or laser ablation under local anesthesia and conscious sedation. Treatment feasibility, technical success, technique efficacy, change in thyroid function tests, side effects, minor and major complications, patients satisfaction and pain/discomfort perception during and after treatment, and disease recurrence during follow-up were recorded.

RESULTS

A total of 13 patients were evaluated, and 11/13 (84.6%) patients (9 female, 2 male, mean age 49.3 ± 8.7 years) resulted suitable for image-guided thermal ablation. All 11 patients agreed to be treated with image-guided thermal ablation. In addition, 3/11 (27.3%) were treated with laser ablation and 8/11 (72.7%) with RFA. All procedures were completed as preoperatively planned (technical success 100%). Technique efficacy was achieved in all 11/11 (100%) cases. Ablated volume significantly reduced from 0.87 ± 0.67 ml at first follow-up to 0.17 ± 0.36 at last follow-up (p = 0.003). No change in thyroid function tests occurred. No minor or major complications occurred. All patients graded 10 the satisfaction for the treatment, and mean pain after the procedure was reported as 1.4 ± 1.7, and mean pain after the procedure as 1.2 ± 1.1 At a median follow-up of 10.2 months (range 1.5-12 months), no local recurrence or distant metastases were found.

CONCLUSIONS

Image guided thermal ablations appear to be feasible and safe in the treatment of PTMC. These techniques hold the potential to offer patients a minimally invasive curative alternative to surgical resection or active surveillance. These techniques appear to be largely preferred by patients.

Thermal Ablation for Small Papillary Thyroid Cancer: A Systematic Review

Background: Although clinical studies indicate that thermal ablation is effective in treating low-risk papillary thyroid microcarcinomas (PTMCs), the effectiveness of this treatment in patients with low-risk PTMC has not yet been systematically evaluated. Methods: Ovid-MEDLINE and EMBASE databases were searched for studies published through May 1, 2019, which report the efficacy of thermal ablation in patients with low-risk PTMCs. Data were extracted and methodological quality was assessed independently by two radiologists according to PRISMA guidelines. Results: This systematic review identified 503 low-risk PTMCs in 470 patients treated by thermal ablation from 9 studies. During follow-up, no patient experienced local tumor recurrence or distant metastasis, whereas two patients (0.4%) experienced lymph node (LN) metastasis. One patient (0.2%) developed a new PTMC, which was successfully treated by additional ablation. Five patients (1.1%) underwent delayed surgery after ablation, including the two patients with LN metastasis and three additional patients with unknown etiology. Conclusions: Thermal ablation is an excellent local tumor control method in patients with low-risk PTMCs. Strict inclusion criteria and technical expertise are required to obtain favorable results.