Efficacy and Safety of Radiofrequency and Ethanol Ablation for Treating Locally Recurrent Thyroid Cancer: A Systematic Review and Meta-Analysis

Differentiated Thyroid Cancer after Thyroidectomy

The widespread use of neck US and other imaging modalities has contributed to a phenomenon of increased detection of differentiated thyroid cancer (DTC). Most of these cancers remain indolent, without requiring surgical intervention. Nonetheless, a subset of patients who require surgical treatment experience subsequent disease recurrence. This most commonly occurs in the cervical lymph nodes and thyroid bed, followed by distant metastasis to the lungs and bones. Because imaging is an integral part of postoperative surveillance, radiologists play a central role in the detection of recurrent tumors and in guiding treatment in these patients. US is the primary imaging modality used for postoperative evaluation. Other modalities such as CT, MRI, radioactive iodine imaging, and PET/CT aid in the accurate diagnosis and characterization of recurrent disease. Therefore, radiologists must have a thorough understanding of the utility of these imaging techniques and the imaging characteristics of recurrent DTC when interpreting these multimodality studies. The interpretation of imaging findings should also be correlated with the clinical status of patients and their biochemical markers to minimize interpretative errors. The authors present a broad overview of the postoperative evaluation of DTC, including its initial primary management, staging, and prognostication; clinical risk stratification for recurrent disease; postoperative surveillance with imaging and evaluation of biochemical markers; and management of recurrent DTC. Published under a CC BY 4.0 license. Supplemental material is available for this article.

Salvage radiofrequency ablation followed by external beam radiotherapy for inoperable recurrent differentiated thyroid cancer

PURPOSE

The treatment of recurrent thyroid cancer with critical organ invasion is challenging. The combination of radiofrequency ablation (RFA) and external beam radiation therapy (EBRT) has been proposed as an effective option. This study evaluates outcomes for inoperable residual/recurrent differentiated thyroid cancer (rDTC) patients treated with RFA followed by EBRT.

MATERIALS AND METHODS

Patients with rDTC treated with RFA followed by EBRT were retrospectively studied. RFA was performed using a free-hand, 'moving-shot' technique under US or CT guidance. For lesions invading critical structures intolerant to 'en bloc' high-temperature RFA, limited-field EBRT using 6- or 10-MV photons was used for adjuvant treatment at a dose of 66 Gy in 33 daily fractions. Toxicities and outcomes were reviewed.

RESULTS

Between April 2020 and January 2022, 11 patients with 14 rDTC lesions underwent RFA followed by EBRT. Five patients had metastatic lesions at rDTC diagnosis. With a median follow-up period of 33.7 months, all patients maintained locoregional control, while achieving a 2-year survival rate of 90.9%. This combined treatment achieved a volume reduction ratio of 92.1% ± 5.1%. The mean nadir thyroglobulin level in patients without initial distant metastases after treatment was 1.40 ± 0.81 ng/ml. Regarding treatment-related complications, one patient (9%) experienced temporary hoarseness after RFA, grade 2 radiation dermatitis occurred in 3 patients (27.2%), and grade 2 dysphagia was noted in 4 patients (36.4%). No grade 3 or greater toxicities occurred.

CONCLUSIONS

Salvage RFA followed by EBRT is feasible, effective and safe for patients with rDTC.

Ablation of Primary and Recurrent Thyroid Cancer: Current and Future Perspectives

Thyroid cancer is the most common endocrine malignancy, and its incidence is increasing, driven in part by the advent of ultrasound, and subsequent increased detection of small, early thyroid cancers. Yet even for small tumors, thyroidectomy with lymph node dissection remains standard of care. Specific to well-differentiated thyroid cancer, surgery has come under scrutiny as a possible overtreatment, in light of stable and favorable survival rates even as guidelines have allowed fewer radical resections and lymph node dissections over time. Moreover, thyroid cancer unfortunately has a known recurrence rate regardless of therapy, and surgical re-intervention for local structural recurrence is eventually limited by scar. Radioactive iodine therapy, another accepted treatment, is minimally invasive but can only treat patients with iodine-avid tumors. For all of these reasons, image-guided thermal ablation has emerged as a valuable complementary tool as a thyroid-sparing, parathyroid-sparing, voice-sparing, repeatable, minimally invasive outpatient focal therapy for both primary and recurrent well-differentiated thyroid cancers. However, the data are still evolving, and this represents a new patient cohort for some interventional radiologists. Therefore, the goal of this review is to discuss the technique and evidence for ablation of patients with thyroid cancer.

Can Ethanol Ablation Achieve Durable Control of Neck Nodal Recurrences in Adults With Stage I Papillary Thyroid Cancer?

Objective

Results of ethanol ablation (EA) for controlling neck nodal metastases (NNM) in adult patients with papillary thyroid carcinoma (APTC) beyond 6 months have rarely been reported. We now describe outcome results in controlling 71 NNM in 40 node-positive stage I APTC patients followed for 66 to 269 months.

Methods

All 40 patients were managed with bilateral thyroidectomy and radioiodine therapy and followed with neck ultrasound (US) for >48 months after EA. Cumulative radioiodine doses ranged from 30 to 550 mCi; pre-EA 27 patients (67%) had 36 additional neck surgeries. Cytologic diagnosis of PTC in 71 NNM selected for EA was confirmed by US-guided biopsy. EA technique and follow-up protocol were as previously described.

Results

The 40 patients had 1 to 4 NNM; 67/71 NNM (94%) received 2 to 4 ethanol injections (total median volume 0.8 cc). All ablated 71 NNM shrank (mean volume reduction of 93%); nodal hypervascularity was eliminated. Thirty-eight NNM (54%) with initial volumes of 12-1404 mm3 (median 164) disappeared on neck sonography. Thirty-three hypovascular foci from ablated NNM (pre-EA volume range 31-636 mm3; median 147) were still identifiable with volume reductions of 45% to 97% observed (median 81%). There were no complications and no postprocedure hoarseness. Final results were considered to be ideal or near ideal in 55% and satisfactory in 45%. There was no evidence of tumor regrowth after EA.

Conclusion

Our results demonstrate that for patients with American Joint Committee on Cancer stage I APTC, who do not wish further surgery or radioiodine, and are uncomfortable with active surveillance, EA can achieve durable control of recurrent NNM.

Ultrasound-guided radiofrequency ablation for the treatment of papillary thyroid carcinoma: a review of the current state and future perspectives

Papillary thyroid carcinoma (PTC) is a highly prevalent cancer that typically exhibits indolent behavior and is associated with a favorable prognosis. The treatment of choice is surgical intervention; however, this approach carries the risk of complications, including scarring and loss of thyroid function. Although active surveillance can mitigate the risk of PTC overtreatment, the possibility of tumor growth and metastasis can elicit anxiety among patients. Ultrasoundguided thermal ablation has emerged as a safe and effective alternative for individuals who are ineligible for or decline surgery. This article provides a review of the clinical research on radiofrequency ablation as a treatment for PTC, offering a thorough examination of its efficacy, safety, and future perspectives.

Radiofrequency Ablation for Benign Nodules and for Cancer, Too?

Radiofrequency ablation (RFA) is a minimally invasive procedure performed under ultrasound guidance that offers the ability to significantly reduce the size of benign thyroid nodules. Although application for benign nodules has only emerged during the past 5 to 10 years in North America, RFA has an impressive track record of nodule reduction, compressive and cosmetic symptom improvement, and excellent safety profile without the morbidity of open surgery. The role of RFA in autonomous functioning nodules, thyroid cancer, and indeterminate nodules is controversial and remains an area of investigation.

Ultrasound-Guided Ethanol Percutaneous Ablation Versus Rescue Surgery in Patients With Locoregional Recurrence of Papillary Thyroid Cancer

OBJECTIVES

Neck recurrence of papillary thyroid cancer (PTC) is frequently detected after initial surgery. The management of these lesions may include rescue surgery (RS) or minimally invasive techniques in selected patients, but comparative studies evaluating the effectiveness and safety of these techniques are lacking. In this paper, we compared ultrasound-guided ethanol ablation (EA) in selected patients to RS in a matched cohort.

METHODS

We retrospectively compared 41 patients and 41 matched PTC patients without known distant metastases, who underwent ultrasound-guided EA or RS (matched reference group), who had 63 and 75 thyroid bed and/or lymph node confirmed PTC recurrences during a median follow-up of 72.8 and 89.6 months, respectively. The primary outcome was time until structural recurrence, compared using Kaplan-Meier survival curves. The secondary outcomes included time until biochemical recurrence, plasma thyroglobulin (Tg) levels, American Thyroid Association (ATA) response-to-therapy categories by the last available observation, and treatment-derived complications in each group.

RESULTS

No significant differences were found between the EA and RS groups for time until structural recurrence (log-rank test, P=0.94). The time until biochemical recurrence was also similar (P=0.51); and the plasma Tg concentration reduction and proportions of patients in the ATA reclassification categories were also similar. A significantly higher proportion of patients in the RS group presented treatment-derived complications (29.27% vs. 9.75%, P<0.05).

CONCLUSION

In this retrospective analysis, the treatment of PTC neck recurrence with EA in selected patients was comparable to RS in a matched reference group for the long-term risk of structural or biochemical relapse, but with a lower risk of treatment-derived complications. These.

RESULTS

support the effectiveness and safety of this minimally invasive technique in the management of selected patients with recurrent PTC.

Percutaneous ethanol injection in thyroid nodular pathology and metastatic cervical adenopathies: A systematic review, meta-analysis and economic evaluation

BACKGROUND

Percutaneous ethanol injection (PEI) has been shown to be a valuable treatment for thyroid nodular pathology and metastatic cervical adenopathies.

OBJECTIVE

To evaluate the effectiveness, safety, and cost-effectiveness of PEI in thyroid nodular pathology and metastatic cervical adenopathies.

METHODS

A systematic review (SR) using meta-analysis was conducted on the effectiveness and safety of PEI. A SR on cost-effectiveness was also performed. The SRs were conducted according to the methodology developed by the Cochrane Collaboration with reporting in accordance with the PRISMA statement. A cost-minimization analysis was carried out using a decision tree model. Assuming equal effectiveness between two minimally invasive techniques (PEI and radiofrequency ablation (RFA)), the model compared the costs of the alternatives with a horizon of six months and from the perspective of the Spanish National Health System.

RESULTS

The search identified three RCTs (n=157) that evaluated PEI versus RFA in patients diagnosed with benign thyroid nodules: ninety-six patients with predominantly cystic nodules and sixty-one patients with solid nodules. No evidence was found on other techniques or thyroid nodular pathology. No statistically significant differences were observed between PEI and RFA in volume reduction (%), symptom score, cosmetic score, therapeutic success and major complications. No economic evaluations were identified. The cost-minimization analysis estimated the cost per patient of the PEI procedure at €326 compared to €4781 for RFA, which means an incremental difference of -€4455.

CONCLUSIONS

There are no differences between PEI and RFA regarding their safety and effectiveness, but the economic evaluation determined that the former option is cheaper.

Management of Recurrent Well-Differentiated Thyroid Carcinoma in the Neck: A Comprehensive Review

Surgery has been historically the preferred primary treatment for patients with well-differentiated thyroid carcinoma and for selected locoregional recurrences. Adjuvant therapy with radioactive iodine is typically recommended for patients with an intermediate to high risk of recurrence. Despite these treatments, locally advanced disease and locoregional relapses are not infrequent. These patients have a prolonged overall survival that may result in long periods of active disease and the possibility of requiring subsequent treatments. Recently, many new options have emerged as salvage therapies. This review offers a comprehensive discussion and considerations regarding surgery, active surveillance, radioactive iodine therapy, ultrasonography-guided percutaneous ablation, external beam radiotherapy, and systemic therapy for well-differentiated thyroid cancer based on relevant publications and current reference guidelines. We feel that the surgical member of the thyroid cancer management team is empowered by being aware and facile with all management options.

Clinical Significance of the Lymph Node Ratio of the Second Operation to Predict Re-Recurrence in Thyroid Carcinoma

The purpose of this study was to establish the risk factors for re-recurrences and disease-specific mortality (DSM) in recurrent thyroid cancer. Patients with recurrent thyroid cancer who underwent initial thyroid surgery from January 2000 to December 2019 at Seoul St. Mary's Hospital (Seoul, Korea) were assessed. Clinicopathological characteristics and long-term oncologic outcomes were compared between patients with one recurrence (n = 202) and patients with re-recurrences (n = 44). Logistic regression and cox-regression analyses were conducted to determine the risk factors for re-recurrences and DSM, respectively. Receiver-operating characteristic curve analysis was performed to determine the cutoff value for lymph node ratio (LNR) as a predictor of re-recurrences. DSM was significantly higher in the re-recurrence group compared with the single-recurrence group (6.8% vs. 0.5%, p = 0.019). Surgical treatment at the first recurrence significantly lowered the risk of re-recurrences. Age (≥55), male sex, and LNR (≥0.15) were independent significant risk factors for re-recurrences in patients who underwent surgery at the first recurrence. Surgical resection is the optimal treatment for initial thyroid cancer recurrence. LNR at re-operation is more effective in predicting re-recurrence than the absolute number of metastatic LNs.

Surgical treatment of thyroid cancer: Established and novel approaches

Thyroid surgery is one of the most common head and neck procedures. The thyroid can be accessed through an anterior cervical incision, or by remote access techniques such as the transoral endoscopic thyroidectomy vestibular approach (TOETVA) which is favored for its ease, safety and direct plane to the thyroid gland. Other novel approaches for targeting small-localized well-differentiated thyroid cancer are by thermal ablation, namely ultrasound guided radiofrequency ablation. These innovative techniques for minimizing a cutaneous scar or for targeting small cancers directly without removal of the gland have developed alongside our realization that low risk well-differentiated thyroid cancer tends to be slow growing and indolent. Up to date, the most robust data supports offering these therapies primarily to patients who would be eligible for active surveillance protocols. In this paper, we review the traditional surgical approaches for removing well-differentiated thyroid cancer, as well as innovative remote access techniques (namely TOETVA), and minimally invasive thermal ablation (namely RFA).

Salvage Cryoablation for Local Recurrences of Thyroid Cancer Inseparable from the Trachea and Neurovascular Structures

PURPOSE

To demonstrate safety, feasibility, and effectiveness of cryoablation of recurrent papillary thyroid cancer ineligible for reoperation because of scarring, eligible for focal ablation as defined within 2015 American Thyroid Association guideline sections C16 and C17.

MATERIALS AND METHODS

With multidisciplinary consensus, cryoablation was performed with curative intent for 15 tumors in 10 patients between January 2019 and July 2021. Demographics, procedural details, and serial postprocedural imaging findings were analyzed.

RESULTS

The mean age was 72.5 years (range, 57-88 years), and 80% of the patients were women. The tumors (mean size, 16 mm ± 6; range, 9-29 mm) received 1 session of cryoablation with 100% technical success. The mean and median postcryoablation tumor volumetric involution rates were 88% and 99%, respectively, with 9 (60%) of 15 tumors involuting completely or down to the scar and 6 (40%) involuting partially at the end of the study period. Tumor size did not increase after cryoablation (0% local progression rate). All tumors abutted the trachea, skin, and/or vascular structures, and hydrodissection failed in all cases because of scarring. The major adverse event rate was 20% (3/15), with 2 cases of voice change and 1 case of Horner syndrome; all resolved at 6 months with no permanent sequelae. No vascular, tracheal, dermal, or infectious adverse events occurred during a mean follow-up of 242 days (range, 114-627 days). One patient died at 386 days after cryoablation because of unrelated cholangiocarcinoma.

CONCLUSIONS

Cryoablation of local recurrences of papillary thyroid cancer abutting the trachea and/or neurovascular structures in the setting of hydrodissection failure because of scarring yielded a mean volumetric involution of 88%, primary efficacy of 60%, and objective response rate of 100% with no local recurrences or permanent complications during a mean follow-up of 242 days. The secondary efficacy and longer-term outcomes remain forthcoming.

Ablation of Cervical Lymph Nodes in Patients with Thyroid Cancer: A Comparison between Cryoablation and Percutaneous Ethanol Injection

The purpose of this brief report was to retrospectively evaluate the safety and efficacy of cryoablation and compare the outcomes with those of percutaneous ethanol injection (PEI) for the treatment of metastatic cervical lymph nodes (CLNs) in patients with thyroid cancer at a single center. The study included 24 patients with 47 CLNs treated with PEI and 7 patients with 11 CLNs treated with cryoablation. Three of 7 (42.9%) patients did not respond to PEI and progressed to cryoablation. There were more local recurrences in CLNs treated with PEI (7/47, 14.9%) compared with cryoablation (0/11, 0%), but this did not reach significance (P = .33). There was no difference in mild/moderate (3/24, 12.5% vs 2/7, 28.6%; P = .31) or severe (1/24, 4.2% vs 0/7, 0%; P = 1) adverse events in the PEI and cryoablation cohorts. The number of treatments required for CLNs treated with PEI (2 ± 1.1) was significantly greater than those for CLNs treated with cryoablation (1 ± 0) (P = .002). These limited data suggest that the treatment of metastatic CLNs with cryoablation or PEI may be safe and effective; however, further data are needed.

Image-Guided Percutaneous Ablation for Primary and Metastatic Tumors

Image-guided percutaneous ablation methods have been further developed during the recent two decades and have transformed the minimally invasive and precision features of treatment options targeting primary and metastatic tumors. They work by percutaneously introducing applicators to precisely destroy a tumor and offer much lower risks than conventional methods. There are usually shorter recovery periods, less bleeding, and more preservation of organ parenchyma, expanding the treatment options of patients with cancer who may not be eligible for resection. Image-guided ablation techniques are currently utilized for the treatment of primary and metastatic tumors in various organs including the liver, pancreas, kidneys, thyroid and parathyroid, prostate, lung, bone, and soft tissue. This article provides a brief review of the various imaging modalities and available ablation techniques and discusses their applications and associated complications in various organs.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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%.

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.

Radiofrequency ablation and related ultrasound-guided ablation technologies for treatment of benign and malignant thyroid disease: An international multidisciplinary consensus statement of the American Head and Neck Society Endocrine Surgery Section with the Asia Pacific Society of Thyroid Surgery, Associazione Medici Endocrinologi, British Association of Endocrine and Thyroid Surgeons, European Thyroid Association, Italian Society of Endocrine Surgery Units, Korean Society of Thyroid Radiology, Latin American Thyroid Society, and Thyroid Nodules Therapies Association

BACKGROUND

The use of ultrasound-guided ablation procedures to treat both benign and malignant thyroid conditions is gaining increasing interest. This document has been developed as an international interdisciplinary evidence-based statement with a primary focus on radiofrequency ablation and is intended to serve as a manual for best practice application of ablation technologies.

METHODS

A comprehensive literature review was conducted to guide statement development and generation of best practice recommendations. Modified Delphi method was applied to assess whether statements met consensus among the entire author panel.

RESULTS

A review of the current state of ultrasound-guided ablation procedures for the treatment of benign and malignant thyroid conditions is presented. Eighteen best practice recommendations in topic areas of preprocedural evaluation, technique, postprocedural management, efficacy, potential complications, and implementation are provided.

CONCLUSIONS

As ultrasound-guided ablation procedures are increasingly utilized in benign and malignant thyroid disease, evidence-based and thoughtful application of best practices is warranted.

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.

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.

Efficacy on radiofrequency ablation according to the types of benign thyroid nodules

Percutaneous radiofrequency ablation (RFA) has been recommended as minimally invasive treatment for patients with symptomatic benign thyroid nodules (BTNs) because of the large number of clinical applications. This retrospective observational study sought to evaluate the clinical outcomes of RFA for BTNs. From 2014 to 2019, a sample size of 1289 patients treated by RFA were 262 ones with solid nodules and 1027 ones with cystic-solid nodule, respectively. The efficacy including the nodule maximal diameter reduction ratio (MDRR), the volume reduction ratio (VRR) and the cosmetic scores reduction ratio (CSRR). The results of the nodule MDRR and VRR in the cystic-solid nodule group were significantly better than those in the solid nodule group at the 3rd and 6th month, and the CSRR in the two groups showed statistically significant difference at the 3rd month. In a word, RFA is an effective method for symptomatic benign solid or cystic-solid nodules. The achieved MDRR and VRR in the cystic-solid nodule group were significantly better than those in the solid nodule group at the 3rd and 6th month.

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 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.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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.

Ultrasonographic characteristics of thyroid nodule rupture after microwave ablation: Three case reports

RATIONALE

Thyroid nodule rupture is a rare complication after microwave ablation (MWA). The ultrasonographic characteristics, clinical course, treatment, or prognosis of thyroid nodule rupture after ablation have not been systematically summarized. Three cases with thyroid nodule rupture after MWA were reported in this study, including the characteristic ultrasound images before ablation and after rupture. Meanwhile, we investigated the etiology, diagnosis, treatment and prevention of the rupture. These findings can provide references for the future clinical practice.

PATIENTS CONCERNS

All 3 patients were pathologically diagnosed as benign thyroid nodules by core needle biopsy and then received 1 session of MWA.

DIAGNOSES

Fourteen days to 1 month after MWA later, all 3 patients presented with abrupt neck pain and swelling, and 1 of them had a fever. Ultrasound examinations shared common features that the rupture of thyroid capsule and a soft-tissue mass with unclear margin in front of the thyroid gland, which connected with the post-ablation nodule. Three patients were diagnosed as thyroid nodule ruptures.

INTERVENTIONS

All 3 patients received conservative management after the ruptures. With the treatment of intravenous antibiotics for 1 week, the neck swelling of patients 1 and 2 both disappeared. The aggravation of neck swelling was found in patient 3. Ultrasonography of the neck revealed irregular fluid echo in the soft-tissue mass, suggesting abscess formation. Aspiration and irrigation were performed. The neck swelling regressed gradually over another 2 weeks with the treatment of antibiotics. Two months after ablation, ultrasound examination showed that the mass had completely disappeared.

OUTCOMES

None of the 3 patients underwent open surgery due to thyroid nodule rupture. At 1-year follow-up, the volume reduction rate of thyroid nodules in 3 patients were as follows: 100%, 98.1% and 90.7%.

LESSONS

Nodule rupture is a rare but severe complication after MWA of the thyroid nodules. The diagnosis can be confirmed by clinical symptoms and ultrasound examination, and most nodule ruptures could be cured with conservative treatment. Grasping the characteristics of ultrasound imaging during the course of disease, and dynamically assessing course of disease progression by ultrasonography could avoid unnecessary imaging examinations or invasive procedures.

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

BACKGROUND

Ultrasound-guided thermal ablation plays an important role in the management of thyroid disease. The objective of this study was to evaluate the feasibility, efficacy, and safety of thermal ablation for patients with solitary T1bN0M0 papillary thyroid carcinoma (PTC) who are ineligible for or unwilling to undergo surgery.

MATERIALS AND METHODS

Data pertaining to 172 patients (38 males and 134 females) who received thermal ablation therapy at 12 hospitals between April 2015 and March 2020 were retrospectively analyzed. The mean duration of follow-up was 24.9 ± 14.1 months (range, 12-60). The technical feasibility, technical success, efficacy, and safety of treatment were analyzed. Postablation tumor size at various time points was compared with preablation measurement.

RESULTS

All patients selected for thermal ablation received enlarged ablation, according to contrast-enhanced ultrasound postablation. The maximum diameter and volume of ablation zone at 6, 12, 18, 24, 36, and 48 months postablation were significantly smaller than those recorded preablation (P < 0.05 for all). At the most recent follow-up, 106 (61.6%) tumors had completely disappeared. The rate of lymph node metastasis was 0.6% (1/172) and the incidence of new tumors was 1.2% (2/172). The overall complication rate was 5.2% (9/172) (major complications: 4.6% [8/172]; minor complications: 0.6% [1/172]). All major complications were relieved within 4 months postablation.

CONCLUSION

Thermal ablation may be a feasible, effective, and safe treatment option for patients with solitary T1bN0M0 PTC who are ineligible for or unwilling to undergo surgery. It may provide a novel treatment option for selected patients.

Ultrasound-guided ethanol sclerotherapy for non-surgical treatment of Warthin's tumor

BACKGROUND

Currently, the first line treatment for Warthin's tumor (WT) is parotidectomy. There is a paucity of data evaluating the safety and efficacy of non-surgical treatments for patients not amenable to surgery. Ultrasound guided ethanol sclerotherapy (UGES) has been successfully used for the management of lymphangiomans of the head and neck, thyroid nodules, and thyroid cysts. This is the first study to implement and assess the success of UGES for management of WT.

METHODS

We report two patients with WT, with a total of 3 masses, who underwent UGES. All procedures were performed in the clinic. The primary outcome measured was the tumor volume reduction rate (VRR), patient satisfaction, and complications observed at follow-up.

RESULTS

Both patients experienced a significant reduction in tumor size upon follow up. VRR for the three treated tumors were 67.30%, 98.32%, and 55.73%. Patient were very satisfied with the results and noted significant cosmetic improvement. No complications were observed at follow-up.

CONCLUSIONS

Ultrasound guided ethanol sclerotherapy may be a viable option for conservative treatment of Warthin's tumor in patients unsuitable or unwilling to undergo surgical resection.

Update of Radiofrequency Ablation for Treating Benign and Malignant Thyroid Nodules. The Future Is Now

Thermal and chemical ablation are minimally invasive procedures that avoid removal of the thyroid gland and target symptomatic nodules directly. Internationally, Radiofrequency ablation (RFA) is among one of the most widely used thermal ablative techniques, and is gaining traction in North America. Surgery remains the standard of care for most thyroid cancer, and in the right clinical setting, Active Surveillance (AS) can be a reasonable option for low risk disease. Minimally invasive techniques have emerged as an alternative option for patients deemed high risk for surgery, or for those patients who wish to receive a more active treatment approach compared to AS. Herein, we review the literature on the safety and efficacy of RFA for treating benign non-functioning thyroid nodules, autonomously functioning thyroid nodules, primary small low risk thyroid cancer (namely papillary thyroid cancer) as well as recurrent thyroid cancer.

Thermal Ablation of Benign Thyroid Nodules and Papillary Thyroid Microcarcinoma

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

Efficacy of radiofrequency ablation for recurrent thyroid cancer invading the airways

OBJECTIVES

To evaluate the efficacy of radiofrequency ablation (RFA) in patients with recurrent thyroid cancer invading the airways.

METHODS

We reviewed patients who had undergone RFA for recurrent thyroid cancer in the central compartment after total thyroidectomy between January 2008 and December 2018. All tumors were classified according to their association with the laryngeal structure and trachea. The volume reduction rate (VRR) and complete disappearance rate were calculated, and their differences were determined relative to the association between the tumor and trachea. Complication rates associated with RFA were evaluated.

RESULTS

The study population included 119 patients with 172 recurrent tumors. Mean VRR was 81.2% ± 55.7%, with 124 tumors (72.1%) completely disappearing after a mean follow-up of 47.9 ± 35.4 months. The complete disappearance rate of recurrent tumors not in contact with the trachea was highest, followed by tumors forming acute angles, right angles, and obtuse angles with the trachea, and tumors with intraluminal tracheal invasion (p value < 0.001). The overall complication rate was 21.4%.

CONCLUSIONS

RFA is effective and safe for the local control of recurrent tumors in the central neck compartment after total thyroidectomy, even for tumors invading the airways, and may be considered an alternative to surgical resection. The inverse relationship between RFA efficacy and airway invasion suggests that early RFA may benefit patients with recurrent tumors in the central neck compartment.

KEY POINTS

• RFA achieved a mean VRR of 81.2% ± 55.7% and complete disappearance of 124 tumors (72.1%) after a mean follow-up of 47.9 ± 35.4 months. • The complete disappearance rate of recurrent tumors not in contact with the trachea was the highest, followed by tumors forming acute angles, right angles, and obtuse angles with the trachea, and tumors with intraluminal tracheal invasion. • Stent-assisted RFA may be a good alternative for palliative treatment of recurrent tumors with intraluminal tracheal invasion.

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.

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.

Thyroid Radiology Practice: Diagnosis and Interventional Treatment of Patients with Thyroid Nodules

갑상선 영상의학 진료란 갑상선 질환 환자를 영상의학적 방법을 활용하여 질병 진단과 중재적 치료를 하는 의료 행위로 정의될 수 있으며 주요 진료 대상은 갑상선 결절 질환 환자들이다. 갑상선 결절의 진단은 일차적으로 초음파 영상진단과 생검에 의해서 이루어지고 결절의 치료는 비수술적 중재적 치료와 갑상선절제술이다. 갑상선 낭종 혹은 낭성우세 양성 결절에서는 에탄올절제술이 일차적 치료법이고 고주파절제술은 고형 혹은 고형우세 양성 결절과 갑상선 재발암 치료에 적용되고 있다. 갑상선 영상의학 진료는 갑상선 결절 질환 환자의 진단 및 비수술적 치료의 대부분을 담당하는 중요한 임상적 역할을 가지고 있으며, 적절한 환자 진료를 위해서는 표준적 진료 지침에 근거하여 진료가 수행되어야 한다. 환자에게 최적의 갑상선 영상의학 진료를 제공하기 위해서는 영상의학과 외래에서 환자를 진료하는 것이 바람직하며 외래 중심의 갑상선 영상의학 진료를 확대하도록 함께 노력해야 할 시점이다.

Ethanol Ablation of Neck Metastases from Differentiated Thyroid Carcinoma

Differentiated thyroid cancer often metastasizes to cervical lymph nodes, characteristically with slow growth rate and low-level aggressiveness. Cervical lymph node resection is the treatment of choice, but ethanol ablation offers a therapeutic option for patients with few nodes unresponsive to radioiodine therapy and who are poor surgical candidates. The ethanol ablation procedure is minimally invasive, guided sonographically, easily and safely repeated, and easily implemented with minimal technology and cost. Transient nerve injury is infrequent and virtually the only important complication. Current experience indicates that ethanol ablation has the safest therapeutic profile compared to surgery and thermal ablation, and the effectiveness is comparable to thermal ablation and approaches that of surgery. Well-designed clinical trials are lacking.

Ultrasound-guided percutaneous microwave ablation of parotid gland adenolymphoma: A case report

RATIONALE

Parotid gland adenolymphoma is one of the most common benign tumors in parotid gland, and mainly treated by surgery. Despite the widespread of ultrasound-guided percutaneous microwave ablation, there is no report concerning its application in parotid gland adenolymphoma. Herein, we reported a 2-year follow-up result of a male patient underwent ultrasound-guided percutaneous microwave ablation for parotid gland adenolymphoma.

PATIENT CONCERNS

A 73-year-old man was admitted due to a hypoechoic nodule measuring 2.67 × 1.42 × 1.35 cm in posterior-inferior area of parotid gland with a high flow velocity in color Doppler flow imaging.

DIAGNOSE

The lesion was pathologically diagnosed as parotid gland adenolymphoma.

INTERVENTIONS

Ultrasound-guided percutaneous microwave ablation was performed to the tumor due to the fact that the patient refused to receive an open surgery in consideration of older age.

OUTCOMES

The ablation procedure lasted about 2 minutes and 15 seconds, without significant adverse effect. The reduction ratios of tumor at postoperative 1 and 3-month were 53% and 82%, respectively. The tumor was fully absent at postoperative 8-month evaluation. Finally, there was no evident recurrence at postoperative 24-month evaluation.

LESSONS

Ultrasound-guided percutaneous microwave ablation is a safe and effective treatment for parotid gland adenolymphoma, which may serve as a novel alternative approach for patients unsuitable for open surgery.

European Perspective on 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: Proceedings of an Interactive International Symposium

BACKGROUND

The American Thyroid Association (ATA) management guidelines for patients with thyroid nodules and differentiated thyroid cancer (DTC) are highly influential practice recommendations. The latest revision appeared in 2015 ("ATA 2015"). These guidelines were developed predominantly by North American experts. European experts frequently have different perspectives, given epidemiological, technological/methodological, practice organization, and medicolegal differences between the respective regions.

SUMMARY

Divergent viewpoints were the focus of an invited symposium organized by the European Association of Nuclear Medicine involving 17 European thyroidologists, four ATA Guidelines Taskforce members, and an audience of 200 international experts. The group discussed the preoperative assessment of thyroid nodules, surgery and the role of pathology, radioiodine (RAI) therapy (RAIT), the assessment of initial therapy and dynamic risk stratification, and the treatment of persistent disease, recurrences, and advanced thyroid cancer. The dialogue resulted in this position paper contrasting European and ATA 2015 perspectives on key issues. One difference pertains to the permissiveness of ATA 2015 regarding lobectomy for primary tumors ≤4 cm. European panelists cited preclusion of RAIT, potential need for completion thyroidectomy, frequent inability to avoid chronic thyroid hormone replacement, and limitations of supportive evidence as arguments against widely applying lobectomy. Significant divergence involved ATA 2015's guidance regarding RAIT. European panelists favored wider use of postoperative RAIT than does ATA 2015. Rationales included the modality's association with favorable patient outcomes and generally limited toxicity, and lack of high-quality evidence supporting withholding RAIT. Additionally, European panelists favored recombinant human thyrotropin (rhTSH) in more settings than does ATA 2015, citing avoidance of hypothyroid morbidity and quality-of-life impairment, without apparent sacrifice in oncologic outcomes. Based on clinical evidence plus theoretical advantages, European experts advocated dosimetric versus fixed-activity RAIT approaches for advanced DTC. European panelists noted that the ATA 2015 risk-stratification system requires information sometimes unavailable in everyday practice. ATA 2015 recommendations regarding RAI-refractory DTC should consider potential palliative benefits of RAIT in patients who also have RAI-susceptible lesions.

CONCLUSIONS

European panelists suggested modifications to approximately one-third of ATA 2015 recommendations. Varying European and ATA 2015 perspectives can stimulate analysis and discussion of the literature and performance of primary research to resolve discrepant recommendations and potentially improve patient outcomes.

mRECIST criteria to assess recurrent thyroid carcinoma treatment response after radiofrequency ablation: a prospective study

PURPOSE

Surgical removal is recommended for recurrent thyroid carcinomas (RTCs) unable to uptake radioiodine and/or not responsive to chemotherapy. However, repeated neck dissection is difficult for surgeons. Thus, radiofrequency ablation (RFA) was proposed for RTCs. The aim of this prospective study is to assess RTC treatment response after RFA, according to well-established criteria.

METHODS

Sixteen lesions in 13 patients were treated by RFA. All patients refused/were excluded from repeated surgery or other conventional therapy. CT and US examinations were performed before RFA to evaluate lesion volume and vascularization. All RFA procedures were performed under US-guidance by an 18-gauge, electrode. Treatment response was evaluated by CT, according to RECIST 1.1 and to mRECIST guidelines; CT examinations were performed during follow-up (6-18 months); the volume of residual vital tumour tissue and the percentage of necrotic tissue were estimated by contrast enhanced CT.

RESULTS

RFA was well tolerated by all patients; in two cases laryngeal nerve paralysis was observed. Mean pre-treatment volume was 4.18 ± 3.53 ml. Vital tumour tissue and percentage of necrosis at 6, 12 and 18 months were 0.18 ± 0.25, 0.11 ± 0.13, 0.29 ± 0.40 ml and 91.9 ± 11.1, 90.4 ± 13.3, 80.8 ± 23.1%. According to RECIST 1.1, target lesion response was classified as complete response (CR) in one case, partial response (PR) in 11/16, stable disease in 4/16 cases. According to mRECIST, 11/16 cases were classified as CR and the remaining 5 as PR.

CONCLUSION

RFA is a safe procedure to treat the viable tumour tissue and to reduce the RTC volume; as to the criteria to assess treatment response, mRECIST appears to be more accurate.

Treatment of lateral neck papillary thyroid carcinoma recurrence after selective lateral neck dissection

BACKGROUND

There is a paucity of data regarding optimal treatment options and outcomes for recurrent disease after lateral neck dissection in patients with papillary thyroid carcinoma.

METHODS

Retrospective review of patients who underwent either percutaneous ethanol injection or surgery for first-time ipsilateral recurrences after ipsilateral lateral neck dissection for papillary thyroid carcinoma was performed.

RESULTS

Follow-up data were available for 54 patients with recurrences in 57 lateral necks treated by either percutaneous ethanol injection (n = 32) or surgery (n = 25). Tumor burden at the time of lateral neck recurrence differed between the groups including the largest lymph node diameter (mean: 13 mm vs 18 mm, P < .01) and the mean number of metastatic lymph nodes identified on ultrasound (1.3 vs 1.9, P = .04). Each modality alone achieved similar estimated rates of disease control at 36 months (75% for percutaneous ethanol injection and 74% for surgery, P = .8) with similar number of reinterventions (1.8 for percutaneous ethanol injection, 1.6 for surgery, P = .6).

CONCLUSIONS

Both ethanol ablation and surgery can achieve disease control in the majority of patients with recurrences after ipsilateral lateral neck dissection for papillary thyroid carcinoma. Ethanol ablation, when used for treatment of a single small lymph node, can result in outcomes that are similar to reoperative surgery for larger and multiple lymph nodes.