Laser and radiofrequency ablations for benign and malignant thyroid tumors

Post-surgical Persistent Hyperparathyroidism Successfully Treated with Parathyroid Radiofrequency Ablation: A Case Report

BACKGROUND

Currently, parathyroidectomy is the standard treatment for Primary Hyperparathyroidism (PHPT). Surgical treatment is often effective, although not free of complications and relapses. Minimally invasive techniques, such as Microwave Ablation (MWA) and Radiofrequency Ablation (RFA), are an alternative to surgery in selected patients. We have, herein, reported on the successful use of RFA in a patient with post-surgical persistent hyperparathyroidism.

CASE PRESENTATION

A 54-year-old woman was referred to our Center for mild hypercalcemia with exams revealing Primary Hyperparathyroidism (PHPT). Neck ultrasound and Technetium- 99 Methoxy-isobutyl-isonitrile (99mTc-MIBI) scintigraphy scanning revealed a suspicious right parathyroid hyperplasia/adenoma. She underwent parathyroidectomy and histological examination showed a parathyroid nodular hyperplasia. During the follow-up, she suffered from persistent hyperparathyroidism due to a left parathyroid hyperplasia. Thus she was treated with RFA. Blood tests after the procedure showed the remission of the disease 7 months post-treatment.

CONCLUSION

A minimally invasive technique for PHPT may represent a valid alternative to surgery, especially in patients with an elevated surgery-related risk. More studies are necessary to investigate the benefit of RFA as a first-line treatment in PHPT.

Histologic Evaluation of Thyroid Nodules Treated with Thermal Ablation: An Institutional Experience

Thyroid nodules are a common, benign condition with a higher prevalence in women, individuals with iodine deficiency, and radiation exposure. Treatment options for benign thyroid nodules include pharmaceutical therapy, thyroidectomy, and thermal ablation (TA). TA, including laser ablation (LA), radiofrequency ablation (RFA), and microwave ablation (MWA), is a procedure that uses heat to cause tissue necrosis. It is commonly used for large, firm, benign, non-functioning thyroid nodules that cause severe symptoms or pain when surgery is not recommended or desired. When thyroid nodules do not respond to TA, they undergo surgery to resolve the symptoms and clarify the diagnosis. This study aims to analyze the histological alterations found in surgically excised TA-treated thyroid nodules and to evaluate the morphological criteria of differential diagnosis between benign and malignant nodules, establishing whether the alterations observed on the histological sample are a consequence of TA or indicative of neoplastic disease. For this purpose, the adoption of ancillary methods, such as immunohistochemistry, is fundamental to distinguish the artifacts induced by TA from the typical morphological characteristics of malignant neoplasms.

Efficacy and safety of ultrasound-guided percutaneous radiofrequency ablation for synovial hyperplasia

PURPOSE

This study aimed to investigate the efficacy and safety of ultrasound-guided percutaneous radiofrequency ablation (RFA) for the treatment of synovial hyperplasia in the knee joints of antigen-induced arthritis (AIA) model rabbits.

METHODS

Forty Japanese large-eared white rabbits were divided into AIA and control groups. After successful induction of the AIA model, the knee joints were randomly assigned to RFA and non-RFA groups. The RFA group underwent ultrasound-guided RFA to treat synovial hyperplasia in the knee joint. Dynamic observation of various detection indices was conducted to evaluate the safety and effectiveness of the RFA procedure.

RESULTS

Successful synovial ablation was achieved in the RFA group, with no intraoperative or perioperative mortality. Postoperative the circumference of the knee joint reached a peak before decreasing in the third week after surgery. The incidence and diameter of postoperative skin ulcers were not significantly different compared to the non-RFA group (p > .05). Anatomical examination revealed an intact intermuscular fascia around the ablated area in the RFA group. The ablated synovial tissue initially presented as a white mass, which subsequently liquefied into a milky white viscous fluid. Gross articular cartilage was observed, along with liquefied necrosis of the synovium on pathological histology and infiltration of inflammatory cells in the surrounding soft tissue.

CONCLUSION

The experimental results demonstrated that ultrasound-guided RFA of the knee in the treatment of synovial hyperplasia in AIA model animals was both effective and safe.

Safety and efficacy of microwave ablation for symptomatic benign thyroid nodules in children

OBJECTIVE

To evaluate the efficacy and safety of microwave ablation (MWA) for the treatment of symptomatic benign thyroid nodules in children.

METHODS

A retrospective study of MWA for the treatment of 34 symptomatic benign thyroid nodules in 25 children was conducted. Volume reduction ratio (VRR), technique efficacy, symptom score, cosmetic score, and thyroid function were used to evaluate the efficacy of the technique. The associated complications and side effects were recorded.

RESULTS

The participants were followed for at least 6 months (median 12 months, range 6-48 months). After MWA treatment, the volumes of the targeted nodules decreased gradually (median volume 5.86 mL before MWA and 0.34 mL at the final follow-up assessment), the VRR achieved was up to 85.03% at the final follow-up assessment, and the technical efficacy at this time was 91.2%. The subjective and objective nodule-related symptoms were also ameliorated. The circulating hormone concentrations reflecting thyroid function remained within their normal ranges in all the participants after one month of follow-up. The procedure had no major complications.

CONCLUSIONS

MWA seems to be an effective and safe technique for the treatment of symptomatic benign thyroid nodules in pediatric patients.

CLINICAL RELEVANCE STATEMENT

Microwave ablation is a safe and effective method to treat symptomatic benign thyroid nodules in pediatric patients. This treatment may be selected if the patient or parents are not suitable or refuse to undergo surgery.

KEY POINTS

• Microwave ablation is effective in reducing the volume of benign thyroid nodules and ameliorating nodule-related symptoms in pediatric patients. • Microwave ablation is a safe method in children, with low complications. • Microwave ablation does not affect the circulating thyroid hormone concentrations of children.

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.

Synergic fabrication of multifunctional liposomes nanocomposites for improved radiofrequency ablation combination for liver metastasis cancer therapy

The field of biomedical research has recently been interested in nanoplatforms with various functionalities, such as cancer drug carriers and MRI and optical imaging, as well as thermal treatment, among other things. As a result of the present investigation, a unique multifunctional liposome (MFL) was established in this investigation. Using radiofrequency-induced imaging and drug release based on magnetic field impact, a dual drug delivery targeted with tumor multi-mechanism treatment was made more effective. The C60 (fullerene) surface was coated with iron nanocomposites to establish the proposed nanosystems, and PEGylation was used (Fe3O4-C60-PEG2000). For fullerene radiofrequency-triggered drug release, thermosensitive DPPC liposomes with folate-DSPE-PEG2000 enveloped the binary nanosystems and doxorubicin (DOX). The in vitro cytotoxicity of the nanocomposites was confirmed by the liver metastasis in HT-29 colon cancer cells using radiofrequency. The flow cytometry analysis confirmed the apoptosis cell death mechanism. The thermal treatment combined chemotherapeutic MFL nano framework transformed radiofrequency radiation from thermoresponsive liposomes, which was noticed both in vivo and in vitro. Due to their superior active tumor targeting and magnetic targeting characteristics, the MFL could also selectively destroy cancerous liver cells in highly co-localized targets.

Different effects of intravenous and local anesthesia in patients undergoing ultrasound-guided radiofrequency ablation of thyroid nodules: a prospective cohort study

PURPOSE

To compare the efficacy and safety of intravenous anesthesia (IV) with local anesthesia (LA) in patients undergoing ultrasound (US)-guided radiofrequency ablation (RFA) of thyroid nodules.

METHODS

50 patients with American Society of Anesthesiologists classification grades I-II undergoing US-guided thyroid RFA were enrolled and randomly (1:1) divided into IV (conscious sedation with Ramsay Sedation Scale [RSS] scores of 2-3 with an anesthesiologist) and LA (subcutaneous anesthesia with lidocaine without an anesthesiologist) groups. Pre-, intra- and post-procedural blood pressure (BP) (SBP₀/DBP₀, SBP₁/DBP₁, and SBP₂/DBP₂), intra- and post-procedural pain (NRS₁ and NRS₂), ablated area volume, treatment time and adverse events were analyzed and compared.

RESULTS

Age, sex, weight, number, nature, volume of nodules, and SBP₀/DBP₀ showed no difference between both groups. 11 and 0 patients' SBP₁/DBP₁ were elevated in the LA and IV groups. NRS₁ differed between both groups. 6 patients in the LA group had moderate or severe pain, but none in the IV group. No between-group difference in SBP₂/DBP₂, NRS₂, ablation completion rate and ablated volume was noted. The median procedure duration differed from 1109 (176) s in IV group and 723 (227) s in LA groups. There was no increased incidence of adverse events in IV group.

CONCLUSIONS

IV with RSS scores of 2-3 maintained intra-procedural BP and relieved intra-procedural pain better, without affecting the ablation efficacy and increasing complications. Despite increased treatment time, IV is a potential option for patients undergoing US-guided RFA of thyroid nodules.

US-CT fusion-guided percutaneous radiofrequency ablation of large substernal benign thyroid nodules

The aim of the present study was to assess feasibility, safety and outcome of ultrasound (US) guided percutaneous radiofrequency (RF) ablation of large substernal benign thyroid nodules assisted by US-computed tomography (CT) fusion imaging and real-time virtual needle tracking (VT) system. Thirty patients (18 females, mean age 56 y, range 32-76 y) with 35 benign nonfunctioning thyroid nodules (mean volume ± SD 26.8 ± 7.6 mL; range 20-38mL) were selected for CT-US fusion guided RF ablation. Nodules' volume was evaluated before treatment and during 12-months follow-up. Complications' rate was also evaluated. US-CT fusion imaging with VT system was feasible in all cases (feasibility 100%) and it was always possible to complete the procedure as planned (technical success 100%). Minor complications occurred in 2/30 cases (6.6%). No major complications occurred. 50% volume reduction (technique efficacy) was achieved in 93% cases, with a significant mean volume reduction at 12 months follow-up (68.7 ± 10.8%), (p < .001). The VT system could be useful in thyroid nodules ablation procedures assistance being able to track the RF electrode tip even when this is obscured by the bubbles produced by the ablative process. The combination of fusion imaging with VT assisted RF ablation represents a safe, non-surgical treatment option for patients with large substernal benign thyroid nodules.

Radiofrequency ablation for liver tumors abutting complex blood vessel structures: treatment protocol optimization using response surface method and computer modeling

OBJECTIVE

To achieve a result of a large tumor ablation volume with minimal thermal damage to the surrounding blood vessels by designing a few clinically-adjustable operating parameters in radiofrequency ablation (RFA) for liver tumors abutting complex vascular structures.

METHODS

Response surface method (RSM) was employed to correlate the ablated tumor volume (Ra) and thermal damage to blood vessels (Dt) based on RFA operating parameters: ablation time, electrode position, and insertion angle. A coupled electric-thermal-fluid RFA computer model was created as the testbed for RSM to simulate RFA process. Then, an optimal RFA protocol for the two conflicting goals, namely (1) large tumor ablation and (2) small thermal damage to the surrounding blood vessels, has been achieved under a specific ablation environment.

RESULTS

Linear regression analysis confirmed that the RFA protocol significantly affected Ra and Dt (the adjusted coefficient of determination Radj2 = 93.61% and 95.03%, respectively). For a proposed liver tumor scenario (liver tumor with a dimension of 4×3×2.9 cm³ abutting a complex vascular structure), an optimized RFA protocol was found based on the regression results in RSM. Compared with a reference RFA protocol, in which the electrode was centered in the tumor with a 12-min ablation time, the optimized RFA protocol has increased Ra  from 98.1% to 99.6% and decreased Dt from 4.1% to 0.4%, achieving nearly the complete ablation of proposed liver tumor and ignorable thermal damages to vessels.

CONCLUSION

This work showed that it is possible to design a few clinically-adjustable operating parameters of RFA for achieving a large tumor ablation volume while minimizing thermal damage to the surrounding blood vessels.

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.

Minimally-invasive treatments for benign thyroid nodules: recommendations for information to patients and referring physicians by the Italian Minimally-Invasive Treatments of the Thyroid group

PURPOSE

In this paper, the members of the Italian Working Group on Minimally-Invasive Treatments of the Thyroid (MITT group) aim to summarize the most relevant information that could be of help to referring physicians and that should be provided to patients when considering the use of MITT for the treatment of benign thyroid nodules.

METHODS

An interdisciplinary board of physicians with specific expertise in the management of thyroid nodules was appointed by the Italian MITT Group. A systematic literature search was performed, and an evidence-based approach was used, including also the knowledge and the practical experience of the panelists to develop the paper.

RESULTS

The paper provides a list of questions that are frequently asked by patients to operators performing MITT, each with a brief and detailed answer and more relevant literature references to be consulted.

CONCLUSIONS

This paper summarizes the most relevant information to be provided to patients and general practitioners/referring physicians about the use of MITT for the treatment of benign thyroid nodules.

Efficacy and safety of ultrasound-guided microwave ablation versus surgical resection for Bethesda category IV thyroid nodules: A retrospective comparative study

OBJECTIVE

The objective of this study was to assess the efficacy and safety of ultrasound-guided microwave ablation (MWA) for Bethesda IV thyroid nodules and to compare the outcomes, complications, and costs of MWA and thyroidectomy.

METHODS

A total of 130 patients with Bethesda IV nodules were retrospectively reviewed, involving 46 in the MWA group and 84 in the surgery group. The local institutional review board approved this study. Patients in the MWA group were followed up at 1, 3, 6, and 12 months after the intervention. Postoperative complications, treatment time, and cost in the two groups were compared.

RESULTS

Among 84 patients with 85 Bethesda IV nodules in the surgery group, postoperative pathology was benign lesions, borderline tumors, papillary thyroid carcinoma, follicular variant papillary thyroid carcinoma, follicular thyroid carcinoma, and medullary carcinoma in 44, 4, 27, 6, 3, and 1 cases, respectively. Malignant thyroid nodules were more prone to solid echostructure (86.11% vs. 72.72%), hypoechogenicity (55.56% vs. 13.63%), and irregular margin (47.22% vs. 13.63%) than benign lesions. The nodule volume reduction rate of patients at 12 months after MWA was 85.01% ± 10.86%. Recurrence and lymphatic and distant metastases were not reported during the follow-up period. The incidence of complications, treatment time, hospitalization time, incision length, and cost were significantly lower in the MWA group than in the surgery group (all p < 0.001).

CONCLUSIONS

MWA significantly reduces the volume of Bethesda IV nodules with high safety and is recommended for those with surgical contraindications or those who refuse surgical resection. Patients with suspicious ultrasound features for malignancy should be actively treated with surgery.

Efficacy of radiofrequency ablation for metastatic papillary thyroid cancer with and without initial biochemical complete status

OBJECTIVE

The application of radiofrequency ablation (RFA) for recurrent thyroid cancer has been demonstrated to effectively manage lesions at critical locations, such as abutting the trachea, with limited complications. Comprehensive investigation of both biochemical (B) and structural (S) change after RFA remains limited. We herein present the first single-center experience of RFA for the treatment of locoregional recurrent thyroid cancer in Taiwan.

DESIGN

23 patients were enrolled, and the treatment responses after RFA were divided into four groups (E, S(+), B(+), and SB(+)), and then compared. The RFA technique, follow-up strategy, changes in pre-and post-operative status, and complications are presented. The volume reduction rate at 1, 3, and 6 months, and the differing responses between lesions abutting/not abutting the trachea are also discussed.

RESULTS

In patients with pre-RFA structural and biochemical incomplete (SB(+)) status, presenting with lesion with an initial maximum diameter of >3.2cm, a higher rate of structural incomplete status at the 6-month follow-up was noted in ROC analysis, with a sensitivity of 57% and specificity of 91%. Favorable structural remission after RFA was noted, and 60.9% of patients achieved biochemical complete status. No significant correlation was noted between the trachea-abutted lesion number and complete remission (p= 0.474). No significant difference in RFA efficacy was noted between the lesions abutting/not abutting the trachea.

CONCLUSIONS

This retrospective study reveals that RFA can achieve both structural and biochemical improvements for locoregionally recurrent thyroid cancer, with a low complication rate. Nearly half of the patients achieved an excellent response after RFA, while a favorable treatment response can be achieved despite the lesion abutting the trachea, with a mean VRR of 84.74%.

A novel parallel overlapping mode for complete ablation of large benign thyroid nodules in a single-session radiofrequency ablation

BACKGROUND

Radiofrequency ablation (RFA) has been widely applied in patients with benign thyroid nodules (BTNs), and complete ablation in a single-session treatment brings great benefits to patients. While how the ablation should be planned and performed to achieve complete ablation in a single-session treatment in large BTNs remains unknown.

PURPOSE

To determine a more suitable ablation strategy for sufficient treatment in a single-session treatment.

MATERIALS AND METHODS

This retrospective study included 108 BTNs receiving RFA treatment. These patients were divided into two groups: group A using one insertion point with a fan-shaped overlapping mode and group B using multiple insertion points with a novel parallel overlapping mode. All the treatments used a hydrodissection approach and moving-shot technique. Contrast-enhanced ultrasonography (CEUS) was used to guide the supplementary ablation. Follow-ups were performed at 1, 3, 6 and 12 months. The rates of supplementary ablation, initial ablation ratio (IAR), the rates of complete ablation (CAR), treatment effects and complications between the two groups were compared.

RESULTS

The group B had larger treated nodules (10.2ml vs 6.4ml, P<0.001) than group A, while group B had a lower rate of supplementary ablation (21.6% vs 75.4%, P<0.001), especially in the BTNs with craniocaudal diameters ≥30mm (22.0% vs 100%, P<0.001). With the assistance of supplementary ablation, both groups achieved similar IAR (100% vs 100%, P=0.372) and CAR (94.7% vs 94.1%, P=1.000). Two groups showed similar VRRs at 12-month follow-up (77.9% vs 77.5%, P=0.894) and similar rates of complications (3.5% vs 2.0%, P=1.000).

CONCLUSIONS

Needle placement using the multiple insertion points with a novel parallel overlapping mode would be easier to achieve complete ablation with less supplementary ablation, especially in large nodules.

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.

Factors related to the absorption rate of benign thyroid nodules after image-guided microwave ablation: a 3-year follow-up

PURPOSE

To assess the absorption rate and factors related to the development of benign thyroid nodules (BTNs) following image-guided microwave ablation (MWA).

MATERIALS AND METHODS

This retrospective study reviewed nodule efficacy in patients who underwent MWA of BTNs between January 2016 and January 2018. The endpoint was a third-year follow-up. Nodules were categorized into those showing complete absorption (volumes with less than 100% volume reduction ratio (VRR) and those showing partial absorption (100% VRR)). Univariable and multivariable regression analyses were carried out to identify variables that were associated with nodule absorption rates.

RESULTS

A total of 173 BTNs (median volume= 4.23 ml; 25-75 percentiles= 2.27-9.00 ml) from 173 patients were evaluated. 49.7% (86/173) of patients had nodules that became completely absorbed. The mean VRRs of all BTNs were 18.0%, 78.7%, 89.0%, 94.5%, and 97.1% at the 1-, 6-,12-, 24- and 36- month follow-ups. At the 3-year follow-up time point, nodule characteristics related to nodule VRR included nodule volume (adjusted odds ratio [AOR], 1.1 [95% CI: 1.0, 1.2]; p = 0.03) and nodule margin (AOR, 5.3 [95% CI: 1.8, 16.0]; p < 0.01). Treatment-related characteristics included energy per ml in nodular volume (AOR, 1.0 [95% CI: 1.0, 1.0]; p < 0.01) and blockage of peripheral flow (AOR, 3.3 [95% CI: 1.3 8.3]; p = 0.01).

CONCLUSIONS

US-guided image-guided MWA results in satisfactory long-term outcomes for the patients with BTNs. Factors related to nodule absorption rate were the volume and margin of the nodule, energy per ml in nodular volume and blockage of peripheral flow.

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.

Small activating RNA-activated NIS gene promotes 131I uptake and inhibits thyroid cancer via AMPK/mTOR pathway

BACKGROUND

Sodium/iodide symporter (NIS) acts as a vital role in regulation of iodide uptake in thyroid cancer. However, the efficient approach to increase NIS expression and the mechanism of NIS-mediated iodide uptake in thyroid cancer remain unclear.

METHODS

Small activating RNA (saRNA) was used to promote NIS expression. And the cell viability, apoptosis, and autophagy were detected using Cell count-kit 8 (CCK-8), Annexin V-FITC/PI double staining, and GFP-LC3 immunofluorescence assays, respectively. The protein levels of caspase 3, Bax, Bcl-2, ATG5, ATG12, LC3B Ⅱ to LC3B Ⅰ, Beclin 1, P62, AMPK, mTOR, P70S6K, actin, and phosphorylation of AMPK, mTOR, P70S6K were determined by western blotting. Moreover, a nude murine node with transplanted NC-dsRNA or NIS-482-transfected SW579 cells was used to examine the effect of NIS-mediated autophagy in vivo. And the levels of caspase 3 and ki67 were examined by immunohistochemical staining assay.

RESULTS

saRNA mediated NIS mRNA and protein upregulated in SW579 cells. saRNA-mediated NIS expression inhibited cell proliferation, induced apoptosis and autophagy, and promoted iodide uptake in SW579 cells. Moreover, the effects of NIS on cells were enhanced by autophagy activator Rapamycin whereas reversed by autophagy inhibitor 3-Methyladenine (3-MA). For mechanism analysis, we found that NIS upregulation exerted the effects on cell proliferation, apoptosis, autophagy, and iodide uptake via regulating AMPK/mTOR pathway. We also demonstrated that saRNA-mediated NIS expression promoted iodide uptake in vivo.

CONCLUSION

saRNA-mediated NIS expression acted as a critical role in increasing iodide uptake via AMPK/mTOR pathway in thyroid cancer.

Image-guided thermal ablation in autonomously functioning thyroid nodules. A retrospective multicenter three-year follow-up study from the Italian Minimally Invasive Treatment of the Thyroid (MITT) Group

OBJECTIVES

To report the results of a multicenter retrospective evaluation of the clinical outcomes of thermal ablation (TA) in a large series of autonomously functioning thyroid nodules (AFTN) with a follow-up protracted up to 3 years.

METHODS

Patients treated with single TA for an AFTN in Italy were included. Changes in nodule volume, TSH values, and ongoing anti-thyroid therapy were assessed at the 2-, 6-, 12-, 24-, and 36-month follow-up controls. Complications and need of any additional therapy after TA were also registered.

RESULTS

A total of 361 patients (244 females, 117 males, median age 58 years, IQR 46-70 years) were included. Nodule volume was significantly reduced at all time points (p < 0.001) (median volume reduction 58% at 6-month and 60% at 12-month). Serum TSH values increased significantly at all time points. After TA, anti-thyroid therapy was withdrawn in 32.5% of patients at 2 months, in 38.9% at 6 months, and in 41.3% at 12 months. A significant difference in the rate of patients who withdrawn medical therapy at 12 months was registered between small (< 10 mL) (74%), medium (49%), or large (> 30 mL) nodules (19%). A single major complication occurred (0.25%). Additional treatments were needed in 34/361 (9.4%) of cases including 4 (1.1%) surgical treatment.

CONCLUSIONS

Image-guided thermal ablation offers a further safe and effective therapeutic option in patients with AFTN. Clinical outcomes are significantly more favorable in small than in large size AFTN.

KEY POINTS

• Thermal ablations (TA) can be safely and effectively used in patients with autonomously functioning thyroid nodules (AFTN). • TA results in a clinically significant nodule volume reduction that is paralleled by TSH level normalization and anti-thyroid drug therapy discontinuation (after TA anti-thyroid therapy was withdrawn in 41.3% at 12 months). • Clinical outcomes after TA are more favorable in small nodules, and when a large amount of thyroid nodule tissue is ablated.

Performance of Contrast-Enhanced Ultrasound in Thyroid Nodules: Review of Current State and Future Perspectives

Ultrasound has been established as a baseline imaging technique for thyroid nodules. The main advantage of adding CEUS is the ability to assess the sequence and intensity of vascular perfusion and hemodynamics in the thyroid nodule, thus providing real-time characterization of nodule features, considered a valuable new approach in the determination of benign vs. malignant nodules. Original studies, reviews and six meta-analyses were included in this article. A total of 624 studies were retrieved, and 107 were included in the study. As recognized for thyroid nodule malignancy risk stratification by US, for acceptable accuracy in malignancy a combination of several CEUS parameters should be applied: hypo-enhancement, heterogeneous, peripheral irregular enhancement in combination with internal enhancement patterns, and slow wash-in and wash-out curve lower than in normal thyroid tissue. In contrast, homogeneous, intense enhancement with smooth rim enhancement and "fast-in and slow-out" are indicative of the benignity of the thyroid nodule. Even though overlapping features require standardization, with further research, CEUS may achieve reliable performance in detecting or excluding thyroid cancer. It can also play an operative role in guiding ablation procedures of benign and malignant thyroid nodules and metastatic lymph nodes, and providing accurate follow-up imaging to assess treatment efficacy.

The Role of CEUS in the Evaluation of Thyroid Cancer: From Diagnosis to Local Staging

Ultrasound often represents the first diagnostic step for thyroid nodule evaluation in clinical practice, but baseline US alone is not always effective enough to achieve thyroid nodule characterization. In the last decades new ultrasound techniques, such as CEUS, have been introduced to evaluate thyroid parenchyma as recommended by EFSUMB guidelines, for use in clinical research field, although its role is not yet clear. Several papers show the potential utility of CEUS in the differential diagnosis of benign and malignant thyroid nodules and in the analysis of lymph node involvement in neoplastic pathology. Therefore, we carried out an evaluation of the literature concerning the role of CEUS in three specific areas: the characterization of the thyroid nodule, the evaluation of minimally invasive treatment and loco-regional staging of the lymph node in proven thyroid cancer. According to evidence reported, CEUS can also play an operative role in nodular thyroid pathology as it is able to guide ablation procedures on thyroid nodule and metastatic lymph nodes, to assess the radicality of surgery, to evaluate disease relapse at the level of the margins of ablated regions and to monitor the clinical evolution of necrotic areas in immediate post-treatment setting.

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.

Matrix 3D ultrasound-assisted thyroid nodule volume estimation and radiofrequency ablation: a phantom study

Background

Two-dimensional (2D) ultrasound is well established for thyroid nodule assessment and treatment guidance. However, it is hampered by a limited field of view and observer variability that may lead to inaccurate nodule classification and treatment. To cope with these limitations, we investigated the use of real-time three-dimensional (3D) ultrasound to improve the accuracy of volume estimation and needle placement during radiofrequency ablation. We assess a new 3D matrix transducer for nodule volume estimation and image-guided radiofrequency ablation.

Methods

Thirty thyroid nodule phantoms with thermochromic dye underwent volume estimation and ablation guided by a 2D linear and 3D mechanically-swept array and a 3D matrix transducer.

Results

The 3D matrix nodule volume estimations had a lower median difference with the ground truth (0.4 mL) compared to the standard 2D approach (2.2 mL, p < 0.001) and mechanically swept 3D transducer (2.0 mL, p = 0.016). The 3D matrix-guided ablation resulted in a similar nodule ablation coverage when compared to 2D-guidance (76.7% versus 80.8%, p = 0.542). The 3D mechanically swept transducer performed worse (60.1%, p = 0.015). However, 3D matrix and 2D guidance ablations lead to a larger ablated volume outside the nodule than 3D mechanically swept (5.1 mL, 4.2 mL (p = 0.274), 0.5 mL (p < 0.001), respectively). The 3D matrix and mechanically swept approaches were faster with 80 and 72.5 s/mL ablated than 2D with 105.5 s/mL ablated.

Conclusions

The 3D matrix transducer estimates volumes more accurately and can facilitate accurate needle placement while reducing procedure time.

Radiofrequency ablation for treatment of thyroid follicular neoplasm with low SUV in PET/CT study

OBJECTIVES

To evaluate the feasibility of radiofrequency ablation (RFA) on follicular neoplasm with low standard uptake value (SUV) in a Positron emission tomography (PET/CT) study.

METHODS

From January 2018 to July 2019, 86 consecutive patients were diagnosed with follicular neoplasm. Of the patients, 28 with PET/CT scans were enrolled in this study. All patients received ultrasound, fine/core needle aspiration, and PET/CT scan prior to treatment. In accordance with previous studies, we recommended 6 patients who had follicular neoplasm with SUVmax ≥5 undergo surgical resection due to an elevated suspicion of malignancy. For 22 patients SUVmax <5, RFA was performed using the moving shot technique. Ultrasound was performed 6 to 12 months after each procedure.

RESULTS

Statistically significant volume reductions during follow-up between values prior to RFA and 12 months post RFA were demonstrated (12.6 ± 20.9 vs. 2.4 ± 3.0 cm³, p < 0.001). Volume reduction ratios at 6-12 months (mean: 10.1 months) after RFA were 73.3% ± 17.7%. One patient presented with vocal cord palsy and recovered within 3 months after RFA. No postprocedural hypothyroidism occurred in the RFA patients.

CONCLUSIONS

By using PET/CT, we can select patients with low SUV follicular neoplasm. RFA offers a safe and feasible alternative treatment option for patients unsuitable or unwilling to undergo surgery.KEY POINTSBy using positron emission tomography-computed tomography, we can distinguish low SUV follicular neoplasm for radiofrequency ablation.For low SUV follicular neoplasm, RF ablation offers a safe and effective alternative treatment option for patients unsuitable or unwilling to undergo surgery.

Radiofrequency ablation versus total thyroidectomy in patients with papillary thyroid microcarcinoma located in the isthmus: a retrospective cohort study

OBJECTIVE

This retrospective study aimed to examine the benefits and complications of radiofrequency ablation (RFA) in patients with papillary thyroid microcarcinoma (PTMC) in the isthmus.

METHODS

This retrospective study included patients with PTMC in the isthmus and treated at the Chinese People's Liberation Army hospital from 05/2014 to 05/2018. The patients were divided into the RFA and total thyroidectomy (TT) groups. The outcomes were operation-related complications, rate of recurrence, metastasis rate, and thyroid carcinoma-specific questionnaire of quality of life (THYCA-QOL).

RESULTS

Among 218 patients, 115 patients underwent RFA, and 103 underwent TT. The rates of disappearance of the ablation zone at 1, 3, 6, 12, and 18 months after RFA were 0.8% (1/115), 10.4% (12/115), 51.3% (59/115), 90.4% (104/115), and 100% (115/115), respectively. Surgical time, blood loss, hospital stays, and treatment costs were higher with TT than with RFA (all p < 0.001). The final THYCA-QOL score of the RFA group was significantly higher than in the TT group (p < 0.001). Minor pain at the operation site was seen in all patients in the RFA group. No distant metastasis was detected in all patients, but one patient in the RFA group had a recurrence after 6 months. The final THYCA-QOL score of the RFA group was significantly lower than in the TT group (p < 0.001).

CONCLUSION

These results suggest that RFA for PTMC in the isthmus had similar outcomes than TT. It will have to be confirmed in future studies.

Vital volume increase versus clinical evaluation as the indication of additional radiofrequency ablation for benign thyroid nodule: a single center retrospective study

Purpose: To compare results in patients treated with additional radiofrequency ablation (RFA) after clinical evaluation or vital volume (Va) increase.Methods: Forty patients with 42 benign thyroid nodules who underwent additional RFA were evaluated in this retrospective study. According to the different indication for additional RFA, 18 patients were divided into Vv increase group (V group) and 22 into clinical evaluation group (C group). Patients were followed up at 1, 3, 6, 12 months and every 12 months thereafter by conventional ultrasound (US), contrast-enhancement ultrasound (CEUS) and clinical evaluation. Volume, volume reduction rate (VRR), symptom score and cosmetic score were evaluated before treatment and each ablation.Results: After the first RFA, there were no statistically differences between two groups in volume, VRR, cosmetic and symptom scores. Compared with the first RFA, volume of all the patients after additional RFA decreased significantly (p < 0.001). In additional RFA, during a mean follow-up time of 10.15 ± 9.17 months, volume in V group was significantly smaller than in C group (2.84 ± 5.43 ml Vs 7.39 ± 13.01 ml, p = 0.046). VRR in V group was significantly larger than in C group (90.18 ± 12.74% Vs 75.66 ± 26.47%, p = 0.007) with significant improvement of cosmetic and symptom scores (p = 0.047; p = 0.030). No complications occurred after each session ablation.Conclusion: Vv increase was a more reliable indicator for additional RFA than clinical evaluation. Additional RFA performed after Vv increase was more effective with respect to volume reduction and improvement of clinical outcomes. Therefore, Vv increase should be set as an indication for additional RFA.

Comparison of thermal ablation and routine surgery for the treatment of papillary thyroid microcarcinoma: a systematic review and Meta-analysis

BACKGROUND

Thermal ablation (TA), as an alternative to surgery, has shown some benefits in the treatment of papillary thyroid microcarcinoma (PTMC) patients, especially for those who are at high risk for surgery or refuse surgery. We performed a systematic review and meta-analysis to evaluate the efficiency, safety, and economy of TA, compared with those of routine surgery (RS), for the treatment of PTMC.

METHODS

PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang, and VIP databases were retrieved from inception to 10 January 2020 to identify relevant original studies on comparison of TA and RS for treatment of PTMC. The recurrence rate, recurrence-free survival (RFS), complication rate, operation time, postoperative length of stay, and cost during the perioperative period were extracted as main indices. The pooled standardized mean difference (SMD) or odds ratio (OR) with 95% confidence intervals (CI) were calculated and analyzed. Chi-square test and I ² statistic were applied to determine the heterogeneity among studies. The sensitivity analysis was applied to explore the origin of heterogeneity, and the publication bias was evaluated by Egger's test.

RESULTS

Seven retrospective studies with a total of 867 patients met the eligibility criteria and were included in the final meta-analysis. Our study demonstrated that TA showed significant reduction in complication with a pooled OR 0.24 (95% CI 0.13 to 0.43), postoperative length of stay with a pooled SMD -3.14 (95% CI -4.77 to -1.51) and cost during the perioperative period with a pooled SMD of -1.69 (95% CI -3.18 to -0.20). It also demonstrated that both TA and RS had similar pooled proportion of recurrence of OR 0.93 (95% CI 0.38 to 2.30) and recurrence-free survive (RFS). The sensitivity analysis showed that each included study had no significant effect on the results and the results were stable and reliable. The Egger's test demonstrated publication bias was acceptable.

CONCLUSIONS

TA may not be oncologically inferior to RS, and it is a relatively safe and economical alternative for the treatment of PTMC.

Residual vital ratio: predicting regrowth after radiofrequency ablation for benign thyroid nodules

PURPOSE

To determine a novel quantitative index, residual vital ratio(RVR) by contrast-enhanced ultrasound(CEUS) with conventional Ultrasound(US), to early predict nodule regrowth after radiofrequency ablation (RFA)for benign thyroid nodules.

METHODS

This retrospective study evaluated 186 patients with 206 benign thyroid nodules underwent RFA. Patients were followed at 1, 3, 6, 12 months and every 12 months thereafter by conventional US, CEUS and clinical evaluation. RVR was defined as the initial ratio of residual vital volume to the total volume calculated by CEUS and conventional US at the first follow-up period after RFA. The relationship between RVR and regrowth was investigated.

RESULTS

The mean volume of thyroid nodules was 10.09 ± 12.90 ml (range 0.40-71.39 ml), which decreased significantly to 2.33 ± 4.65 ml (range 0-36.75 ml) (p < .001) after a mean follow-up time of 22.50 ± 13.29 months (range 6-68 months) with a mean VRR as 85.26 ± 15.02% (range 32.23-100%). The overall incidence of regrowth was 12.62% (26/206) and the mean timing of regrowth was 20.77 ± 12.03 months (range 6-48 months). Multivariate logistic regression revealed that RVR (OR = 1.050, 95%CI 1.025-1.075), initial volume(OR = 1.033, 95%CI 1.000-1.066), location close to critical structures (OR = 5.967, 95%CI 1.898-18.760) and vascularity (OR = 2.216, 95%CI 1.185-4.143) were independent factors associated with regrowth. According to receiver-operating characteristic curve, the area under curve for RVR to regrowth was 0.819 (95% CI 0.740-0.897, p < .001) with the optimal cutoff value of 44.5% (sensitivity 80.8%, specificity 74.7%).

CONCLUSION

RVR was not only an independent factor but also an early quantitative predictor for regrowth. If RVR was larger than 44.5%, the nodule tended to regrowth in the follow-up.

European Thyroid Association and Cardiovascular and Interventional Radiological Society of Europe 2021 Clinical Practice Guideline for the Use of Minimally Invasive Treatments in Malignant Thyroid Lesions

The growing detection of papillary thyroid microcarcinomas (PTMCs) is paralleled by an increase in surgical procedures. Due to the frequent indolent nature, cost, and risk of surgery, active surveillance (AS) and ultrasound-guided minimally invasive treatments (MITs) are in suitable cases of incidental PTMC proposed as alternatives to thyroidectomy. Surgery and radioiodine are the established treatments for relapsing cervical differentiated thyroid carcinoma (DTC) metastases. But radioiodine refractoriness, risk of surgical complications, adverse influence on quality of life, or declining repeat surgery have led to AS and MIT being considered as alternatives for slow-growing DTC nodal metastases. Also, for distant radioiodine-refractory metastases not amenable to surgery, MIT is proposed as part of a multimodality therapeutic approach. The European Thyroid Association and the Cardiovascular and Interventional Radiological Society of Europe commissioned these guidelines for the appropriate use of MIT. Based on a systematic PubMed search, an evidence-based approach was applied, and both knowledge and practical experience of the panelists were incorporated to develop the manuscript and the specific recommendations. We recommend that when weighing between surgery, radioiodine, AS, or MIT for DTC, a multidisciplinary team including members with expertise in interventional radiology assess the demographic, clinical, histological, and imaging characteristics for appropriate selection of patients eligible for MIT. Consider TA in low-risk PTMC patients who are at surgical risk, have short life expectancy, relevant comorbidities, or are unwilling to undergo surgery or AS. As laser ablation, radiofrequency ablation, and microwave ablation are similarly safe and effective thermal ablation (TA) techniques, the choice should be based on the specific competences and resources of the centers. Use of ethanol ablation and high-intensity focused ultrasound is not recommended for PTMC treatment. Consider MIT as an alternative to surgical neck dissection in patients with radioiodine refractory cervical recurrences who are at surgical risk or decline further surgery. Factors that favor MIT are previous neck dissection, presence of surgical complications, small size metastases, and <4 involved latero-cervical lymph nodes. Consider TA among treatment options in patients with unresectable oligometastatic or oligoprogressive distant metastases to achieve local tumor control or pain palliation. Consider TA, in combination with bone consolidation and external beam radiation therapy, as a treatment option for painful bone metastases not amenable to other established treatments.

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.

A contemporary look at thyroid nodule management. What every Saudi physician and surgeon should know

There has been substantial changes to the methods of thyroid nodule management in the past decade, including new guidelines for performing thyroid ultrasound and biopsy. Genetic tests are now routinely used in some centers to aid in the diagnosis of thyroid nodules. Novel management options, including alcohol, laser, and radio frequency ablation have also gained popularity in the past few years. Considering the continuous increase in access to healthcare facilities in Saudi Arabia, we are expecting an upcoming epidemic of small incidentally detected thyroid nodules. This study highlights the major recent advancements in thyroid nodule management that are relevant to every Saudi physician and surgeon.

Efficacy and safety of microwave ablation for cervical metastatic lymph nodes arising post resection of papillary thyroid carcinoma: a retrospective study

Purpose: To evaluate the efficacy and safety of microwave ablation (MWA) for cervical metastatic lymph nodes (LNs) post resection of papillary thyroid cancer (PTC).Materials and methods: From November 2015 to November 2018, 14 patients with 38 cervical metastatic LNs treated by MWA were included in this retrospective study. Wilcoxon signed rank test was used to compare the changes of LN and serum thyroglobulin levels pre- and post-ablation.Results: The technical success rate in this study was 100% (38/38). The mean follow-up time was 23.6 ± 9.3 months. On pre-ablation contrast-enhanced ultrasound, 25 LNs showed high-enhancement, 8 LNs showed iso-enhancement, and 5 LNs showed low-enhancement. The median largest diameter of LNs at pre-ablation and 3, 6, 9, 12, 18, 24, and 36 months post-ablation was 11.5 mm and 9.5, 9.0, 8.0, 8.0, 8.0, 7.0, and 6.0 mm, respectively. The median volume of LNs at pre-ablation and 3, 6, 9, 12, 18, 24, and 36 months post-ablation were 251.2 mm³ and 206.7, 167.2, 166.2, 155.7, 153.9, 153.9, and 113.1 mm³, respectively. The largest diameter and the volume of the cervical metastatic LNs at the last post-ablation was significantly smaller than the pre-ablation level (p = .0016; p = .0018). Serum Tg level at the last post-ablation (median 1.25 ng/mL) was significantly lower than the pre-ablation level (median 8.35 ng/mL) (p = .001). There were no complications.Conclusion: MWA is a safe and effective novel treatment option for cervical metastatic LN that emerge post resection of PTC.

Inter-observer reliability in ultrasound measurement of benign thyroid nodules in the follow-up of radiofrequency ablation: a retrospective study

PURPOSE

To investigate the inter-observer reliability of ultrasound (US) measurement in volume and volume reduction rate (VRR) of benign thyroid nodules during the follow-up of radiofrequency ablation (RFA).

MATERIALS

This retrospective study evaluated 76 patients with 88 benign thyroid nodules who underwent RFA. Two independent observers performed the US measurements during the same follow-up visit. The Bland-Altman analysis was used to evaluate the inter-observer reliability of volume and VRR (logarithmic transformation). The mean difference and 95% limits-of-agreement (LOA) were obtained after antilogarithm.

RESULTS

No significant differences were found in the volume and VRR measurements during a mean follow-up time of 35.52 ± 12.82 months. After antilogarithms, the mean difference of volume was 0.9961, 0.9987, 1.0016, 0.9972, 0.9977 and 0.9969 at 1, 3, 6, 12, 24 and 36 months, respectively. The 95% LOA of volume became wider over the follow-up period, and the largest one was between 0.8471 and 1.1733 at 36 months. The 95% LOA of VRR became narrower over the follow-up period, and the largest one was between 0.9541 and 1.0469 at 1 month. The incidence of regrowth was 20.45% and the largest 95% LOA of regrowth nodules was between 0.9028 and 1.284 at 12 months. At the same follow-up period, VRR had a narrower 95% LOA than volume. Compared with volume ≥10 ml, nodules <10 ml revealed a larger 95% LOA in both the volume and VRR.

CONCLUSION

The inter-observer reliability of the US measurements of benign thyroid nodules during the follow-up period of RFA was acceptable. The variation by different observers could not affect the evaluation of efficacy.

Neural monitoring during ultrasound-guided radiofrequency ablation of thyroid nodules

BACKGROUND

Intraoperative neurological monitoring is important in locating and assessing nerves during surgery. This study aimed to investigate the feasibility of neural monitoring during ultrasound-guided radiofrequency ablation (RFA) of thyroid nodules.

METHODS

From February 2019 to August 2019, 16 patients (age, 42.8 ± 15.9 years; range, 17-74 years) with benign thyroid nodules who underwent ultrasound-guided RFA with neural monitoring in Zhongshan Hospital, Xiamen University, were included. A neuromonitoring system stimulated the vagus nerve to obtain electromyographic (EMG) signals and predict the function of recurrent laryngeal nerves (RLNs) during RFA. The hydrodissection technique was used to protect the RLN area. Thyroid nodules were treated with the moving-shot technique. The EMG signal value results were recorded and analyzed. All patients underwent laryngoscopic investigation 1 day after the procedure.

RESULTS

Twenty vagus nerves were stimulated preprocedure and postprocedure, and the EMG signals were successfully recorded (100%). The mean initial (before ablation) and final (final ablation) vagus nerve amplitudes were 612.7 ± 130.4 μV (range, 455-882 μV) and 592.7 ± 127.3 μV (range, 410-817 μV), respectively. Based on the EMG signals, all 20 RLNs were judged to be in good condition, consistent with the postprocedure laryngoscopic results. The maximum lesion size and volume at 6 months after RFA were significantly lesser than those at baseline (p < 0.05). The volume reduction rate was 68.5% ± 21.5% (range, 13.0-97.3%). Cosmetic and symptom scores were significantly lower than those at baseline. No complications from neural monitoring occurred.

CONCLUSIONS

Neural monitoring during ultrasound-guided RFA of thyroid nodules is feasible to predict RLN function.

Treating thyroid nodules by radiofrequency: is the delivered energy correlated with the volume reduction rate? A pilot study

OBJECTIVE

Radiofrequency ablation (RFA) was proven as effective in reducing thyroid nodules' volume. However, whether technical procedure aspects could influence the volume reduction rate (VRR) has not been clarified. This retrospective pilot study aimed to analyze the correlation of RFA power, duration, and energy with VRR.

METHODS

During the period from June to December 2018 two primary-care centers treated benign thyroid nodules of adult outpatients according to the same RFA procedure. Technical parameters to be investigated were the following: median power (P_median), effective time of treatment (T_eff), energy calculated as P_median × T_eff (E_calc), and energy delivered per mL as Kcal × 4184 × nodule's volume (E_del). Continuous variables were analyzed by the Mann-Whitney test. Data of 1-year posttreatment follow-up were collected on December 2019 and the correlation of the above parameters with VRR was analyzed by linear regression.

RESULTS

Forty-one nodules were included and their 1-year VRR was 66.6%. RFA was performed with a P_median of 55 W, T_eff 10.24 min, E_calc 31,380 J, and E_del 1473 J/mL. E_del was significantly correlated with VRR (p = 0.014) while P_median, T_eff, and E_calc not. A strong correlation of E_del with VRR was found in nodules <10 mL (p = 0.001) while no significant correlation was observed in nodules >10 mL.

CONCLUSIONS

This study showed that the energy delivered with RFA is the only technical parameter significantly correlated with the VRR of thyroid nodules.

European Thyroid Association Survey on Use of Minimally Invasive Techniques for Thyroid Nodules

OBJECTIVE

Image-guided interventional ultrasound (US) techniques represent diagnostic and therapeutic tools for non-surgical management of thyroid nodular disease. We sought to investigate the attitude of European Thyroid Association (ETA) members towards the use of minimally invasive techniques (MIT) in diagnosis/therapy of symptomatic nodular goitre.

METHODS

ETA members were invited to participate in an online survey investigating the use of MIT in benign and malignant thyroid nodular disease. Of 865 invited members, 221 (25.5%) completed the survey. The respondents were from 40 countries; 139 (74.7%) were from European countries.

RESULTS

Respondents personally performed thyroid US (91.6%), Fine needle aspiration (FNA; 75.3%), ethanol ablation (EA; 22.1%), core needle biopsy (CNB; 11%) and thermal treatments (4.8%). When skills and/or technology were unavailable, only 13.4% referred patients "often" or "always" to other centres with specific expertise in this field. Surgery was the preferred first option in patients with recurrent cysts, 4.0 cm benign nodules, local (radioiodine-avid or non-avid) lymph node metastases, or papillary cancers <1.0 cm. For autonomously functioning nodules radioactive iodine treatment was the preferred choice, followed by surgery. Thermal ablation (TA) was the preferred option only for a 4 cm benign nodule in old patients with comorbidities.

CONCLUSIONS

US, US-guided FNA and surgery were available to nearly all respondents, while MIT was not. CNB and EA were employed only by about 1/3 of the respondents and TA procedures were available and personally performed only by a minority. For most thyroid lesions, surgery was the preferred option versus thermal therapies. The ETA needs to develop guidelines and establish teaching to overcome geographic inequality and promote the use of MIT as a valid therapy option in appropriate cases.

Reproducibility of Ablated Volume Measurement Is Higher with Contrast-Enhanced Ultrasound than with B-Mode Ultrasound after Benign Thyroid Nodule Radiofrequency Ablation-A Preliminary Study

The reproducibility of contrast-enhanced ultrasound (CEUS) and standard B-mode ultrasound in the assessment of radiofrequency-ablated volume of benign thyroid nodules was compared. A preliminary study was conducted on consecutive patients who underwent radiofrequency ablation (RFA) of benign thyroid nodules between 2014 and 2016, with available CEUS and B-mode post-ablation checks. CEUS and B-mode images were retrospectively evaluated by two radiologists to assess inter- and intra-observer agreement in the assessment of ablated volume (Bland–Altman test). For CEUS, the mean inter-observer difference (95% limits of agreement) was 0.219 mL (-0.372–0.809 mL); for B-mode, the mean difference was 0.880 mL (-1.655–3.414 mL). Reproducibility was significantly higher for CEUS (85%) than for B-mode (27%). Mean intra-observer differences (95% limits of agreement) were 0.013 mL (0.803–4.097 mL) for Reader 1 and 0.031 mL (0.763–3.931 mL) for Reader 2 using CEUS, while they were 0.567 mL (-2.180–4.317 mL, Reader 1) and 0.759 mL (-2.584–4.290 mL, Reader 2) for B-mode. Intra-observer reproducibility was significantly higher for CEUS (96% and 95%, for the two readers) than for B-mode (21% and 23%). In conclusion, CEUS had higher reproducibility and inter- and intra-observer agreement compared to conventional B-mode in the assessment of radiofrequency-ablated volume of benign thyroid nodules.

A Novel Strategy for Single-Session Ultrasound-Guided Radiofrequency Ablation of Large Benign Thyroid Nodules: A Pilot Cohort Study

Background: Ultrasound-guided radiofrequency ablation (RFA) of thyroid nodules (TNs) is a minimally invasive procedure that has been widely used to induce volume reduction in symptomatic solid benign TNs. The goal of this study was to investigate a novel therapeutic approach for single-session ablation of large thyroid nodules (LTNs, vol > 20 ml). Methods: We performed a pilot cohort study of 21 patients with symptomatic solid benign LTNs (vol > 20 ml), who accepted ultrasound-guided RFA treatment between September 2018 and November 2019. RFA was performed using an 18-gauge internally cooled electrode with ultrasonographic guidance in a single session combined with intraoperative hydrodissection and immediate contrast-enhanced ultrasound (CEUS) to optimize safety and efficacy. Nodule volume was evaluated before ablation and at 1, 3, and 6 months after initial ablation, and all patients were asked to assess the cosmetic score (from 1 to 4) and symptom score (from 0 to 10) before ablation and at every follow-up after ablation. Results: At the 6 month follow-up, there was significant nodule volume reduction, from 27.49 ml ± 7.9 (standard deviation) to 3.82 ml ± 5.02 (p = 0.001). Cosmetic signs (p = 0.001) and pressure symptoms (p = 0.001) were significantly improved. All patients underwent RFA without any major complications, and very few patients developed a change in voice (2/21). However, the changes subsided within 1 month. Almost half of the patients received an additional RFA (11/21) treatment to achieve complete ablation on the intraoperative immediate CEUS evaluation. Conclusion: RFA is effective for treating LTNs (vol > 20 ml) and controlling clinical symptoms with a low complication rate. Patients were satisfied with cosmetic sign and pressure symptom improvement. The intraoperative hydrodissection and immediate CEUS represent a novel therapeutic approach for single-session ablation of LTNs.

The Ablation of Thyroid Nodule's Afferent Arteries Before Radiofrequency Ablation: Preliminary Data

Induced radiofrequency thermal ablation is the cytoreductive treatment of symptomatic benign thyroid nodules, metastatic and recurrent thyroid tumors and papillary thyroid microcarcinomas. It is a safe and effective alternative to surgery and it allows to obtain satisfactory results in terms of volumetric reduction of the nodule with significant improvement in the quality of life. The trans-isthmic approach and the moving shot technique are the two basic techniques; however, an advanced technique, artery-first feeding radiofrequency ablation, has been developed and validated. We have prospectively included 29 consecutive patients who have undergone radiofrequency ablation (Group A) or artery- first vRFA (Group B). All included patients had a diagnosis of benign nodular goiter and they underwent a single session of radiofrequency ablation. All patients followed a follow-up program at 1 month, 3 months, and 6 months. Continuous variables (age, TSH value, basal volume of nodule, used Joule, time in second of the procedure, nodules' volume at 1-, 3-, and 6- months of follow-up and percentage of volume reduction at 1-, 3-, and 6- months of follow-up) were described as mean, standard deviation and range, while categorical variables (gender, nodule structure and nodule vascularization) were described as number of cases and percentage. Independent samples t-test were performed to compare the continuous variables. A Test of Proportions was applied to the categorical variables. The Fisher's exact test was used to analyze the gender. Statistical significance was considered in case of p-value <0.05. Solid structure and spongiform structure showed statistic differences with p-values of 0.022 and 0.023 respectively between two groups. The percentage of reduction at 1 month did not show a significant difference between two groups; instead, the percentage of volume reduction was decreased mostly in the Group B at 3 months and 6 months of follow-up with a p-value of 0.003 and 0.013, respectively. The Joules/energy used showed a statistically significant difference (p-value=0.05), more energy must be used in vascular radiofrequency ablation. These data allow us to hypothesize that vRFA may improve the effectiveness of the procedure, allowing for a reduction in volume more quickly. They were preliminary but promising results, clearly a larger series of cases and prolonged follow-up are needed to clarify and confirm our observations.

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.