Efficacy and Safety of Radiofrequency Ablation for Benign Thyroid Nodules: A Prospective Multicenter Study.

Objective: To assess the efficacy and safety of thyroid radiofrequency (RF) ablation for benign thyroid nodules by trained radiologists according to a unified protocol in a multi-center study. Materials and Methods: From 2010 to 2011, 345 nodules from 345 patients (M:F = 43:302; mean age ± SD = 46.0 ± 12.7 years, range = 15-79) who met eligibility criteria were enrolled from five institutions. At pre-ablation, the mean volume was 14.2 ± 13.2 mL (1.1-80.8 mL). For 12 months or longer after treatment, 276 lesions, consisting of 248 solid and 28 predominantly cystic nodules, were followed. All operators performed RF ablation with a cool-tip RF system and two standard techniques (a transisthmic approach and the moving-shot technique). Volume reduction at 12 months after RF ablation (the primary outcome), therapeutic success, improvement of symptoms as well as of cosmetic problems, and complications were evaluated. Multiple linear regression analysis was applied to identify factors that were independently predictive of volume reduction. Results: The mean volume reduction at 12 months was 80.3% (n = 276) and at the 24-, 36-, 48-, and 60-month follow-ups 84.3% (n = 198), 89.2% (n = 128), 91.9% (n = 57), and 95.3% (n = 6), respectively. Our therapeutic success was 97.8%. Both mean symptom and cosmetic scores showed significant improvements (p < 0.001). The rate of major complications was 1.0% (3/276). Solidity and applied energy were independent factors that predicted volume reduction. Conclusion: Radiofrequency ablation performed by trained radiologists from multiple institutions using a unified protocol and similar devices was effective and safe for treating benign thyroid nodules.

Radiofrequency ablation of small follicular neoplasms: initial clinical outcomes.

BACKGROUND: In thyroid gland, radiofrequency ablation (RFA) has been applied to both recurrent cancers and benign nodules, although, according to the American Thyroid Association (ATA) and the Korean Society of Thyroid Radiology (KSThR) guidelines, surgery is the first-line treatment for follicular neoplasm. However, it has been argued that follicular neoplasm with lower risk of malignancy can be managed by close follow-up. In this study, we evaluated the effectiveness of RFA of small follicular neoplasms, examining reductions in volume and related clinical problems, and making observations over long-term follow-up. METHODS: We evaluated 10 follicular neoplasms in 10 patients who were treated with RF ablation between 2009 and 2011. A RF generator and an 18-gauge internally cooled electrode were used to perform complete ablation of the whole nodules. Changes in nodules or ablated zones on follow-up ultrasound, and complications during and after RF ablation were evaluated. RESULTS: The mean follow-up period was 66.4 ± 5.1 months (range: 60-76 months). In eight patients, single session of RF ablation was sufficient, while two patients required two sessions. There was a significant reduction in the mean volume (99.5 ± 1.0%) of lesions, with eight ablated lesions (8/10, 80%) disappearing completely on follow-up. No recurrences were found in any ablated zones at last follow-up. Transient mild neck pain (n = 6) occurred during the procedure without requiring any medication. CONCLUSION: In addition to active surveillance, RF ablation may be an effective and safe alternative for the management of patients with small (<2 cm) follicular neoplasm suspected on thyroid biopsy and who strongly refuse surgery.

Efficacy and Safety of Radiofrequency Ablation Versus Observation for Nonfunctioning Benign Thyroid Nodules: A Randomized Controlled International Collaborative Trial.

BACKGROUND: Percutaneous radiofrequency thermal ablation (RFA) has been reported as an effective tool for the management of benign thyroid nodules (BTN). However, large, randomized controlled trials (RCTs) are lacking. OBJECTIVE: The aims of this study were to assess the volume reduction of BTN after a single RFA performed using the moving-shot technique and to compare the volume reduction obtained in patients treated in two centers with different experience of the moving-shot technique. METHOD: This study was an international prospective RCT. It was carried out at the Mauriziano Hospital (Turin, Italy) and the Asan Medical Center (Seoul, Korea). Eighty patients harboring solid, compressive, nonfunctioning BTN (volume 10-20 mL) were enrolled. Twenty patients in each country were treated by RFA using a 18-Gauge internally cooled electrode (group A); 20 nontreated patients in each country were followed as controls (group B). RESULTS: At six months, BTN volume significantly decreased in group A (15.1±3.1 mL vs. 4.2±2.7 mL; p<0.0001), whereas it remained unchanged in group B (14.4±3.3 mL vs. 15.2±3.5 mL). The baseline volume was larger in the Italian series (16.4±2.5 mL vs. 13.9±3.3 mL, p=0.009). However, at six months, there was no significant difference between the Korean group and the Italian group (3.7±2.9 mL vs. 5.5±2.2 mL). Both cosmetic and compressive symptoms significantly improved (3.6±0.5 vs. 1.7±0.4 and 3.6±1.9 vs. 0.4±0.7, respectively; p<0.001). No side effects occurred. CONCLUSIONS: RFA was effective in reducing the volume of BTN. The outcome was similar in centers with different experience in the moving-shot technique.

Radiofrequency ablation for autonomously functioning thyroid nodules: a multicenter study.

BACKGROUND: The purpose of this study is to validate the generalizability of the efficacy and safety of radiofrequency (RF) ablation for treating autonomously functioning thyroid nodules (AFTN) in a large population multicenter study. METHODS: This study included 44 patients from 5 institutions who refused or were not suitable for surgery or radioiodine therapy. Twenty-three patients were affected by a toxic nodule and 21 by a pretoxic nodule. RF ablation was performed using an 18-gauge, internally cooled electrode. Nodule volume, thyroid function, scintigraphy, symptom/cosmetic scores, and complications were evaluated before treatment and during each follow-up. RESULTS: The mean follow-up period was 19.9±12.6 months. The mean nodule volume was initially 18.5±30.1 mL and significantly decreased after treatment at 1 month (11.8±26.9 mL, p<0.001) and the last month (4.5±9.8 mL, p<0.001). Significant improvement of triiodothyronine, free thyroxine, and thyrotropin was observed at the last follow-up. Regarding scintigraphy, 35 hot nodules became cold or were normal when scanned and 9 decreased uptake, although they remained hot nodules. The mean symptom and cosmetic scores were significantly reduced at the last follow-up. No major complications were encountered. CONCLUSIONS: This multicenter study validated the efficacy and safety of RF ablation for treating AFTN; RF ablation can be considered an alternative to surgery or radioiodine therapy.

Single-session treatment of benign cystic thyroid nodules with ethanol versus radiofrequency ablation: a prospective randomized study.

PURPOSE: To compare volume reduction of single-session ethanol ablation (EA) and radiofrequency (RF) ablation for cystic thyroid nodule treatment. MATERIALS AND METHODS: All patients gave written informed consent to participate in this prospective institutional review board-approved study. From May 6, 2010, to August 8, 2011, in this single-institutional, noninferiority trial, 50 patients, each with a single cystic thyroid nodule, were randomly assigned to EA (25 patients; mean age for women, 45.7 years, and for men, 37.5 years) or RF ablation (25 patients; mean age for women, 45.1 years, and for men, 43.7 years) treatment. Internal fluid was aspirated prior to EA or RF ablation. Primary end point was the volume reduction ratio (percentage) at 6-month follow-up; the noninferiority margin was chosen as -8% (EA minus RF ablation). Secondary end points included therapeutic success rate, improvement of symptoms and cosmetic problems, and number of major complications. Analysis was performed primarily in intention-to-treat manner. A one-sided 95% confidence interval (CI) for the mean difference in volume reduction ratio 6 months after treatment was calculated to test for noninferiority. Subsequent superiority comparison of EA with RF ablation on a condition of establishment of the noninferiority of EA to RF ablation was preplanned and used two-sided 95% CI of the outcome difference. RESULTS: The mean volume reduction was 96.9% in EA and 93.3% in RF ablation (n = 21 for each) (difference, 3.6%; lower bound of the one-sided 95% CI of the difference, 1.2%), thus demonstrating the noninferiority of EA to RF ablation. Two-sided 95% CI of the outcome difference was 0.7% to 6.5%, demonstrating significant superiority of EA to RF ablation. All patients demonstrated therapeutic success (P > .99). Mean symptom and cosmetic scores showed no significant difference in either group (P = .806 and P = .682, respectively). There were no major complications (P > .99). CONCLUSION: EA may be the first-line treatment modality for cystic thyroid nodules, which has comparable therapeutic efficacy to, but is less expensive than, RF ablation.

Symptomatic nonfunctioning parathyroid cysts: role of simple aspiration and ethanol ablation.

OBJECTIVES: To evaluate the outcomes of simple aspiration and ethanol ablation in the management of symptomatic nonfunctioning parathyroid cyst (PC). METHODS: We performed simple aspirations for 12 PCs in 12 patients from March 1997 to June 2010. PC was diagnosed if the aspirated fluid was clear colorless and showed an elevated parathyroid hormone (PTH) level. Ethanol ablation (EA) was performed for recurrent PCs. Simple aspirations were performed using 23-gauge needles and EAs using 18-gauge needles with 99% ethanol under ultrasound (US) guidance. We evaluated cyst volume, cosmetic score, symptom score, and complications. RESULTS: Mean follow-up period of all patients was 19.2 ± 12.9 months (median, 15.0 months; range, 7-40 months). Simple aspiration was successful in four patients, and the mean volume reduction after simple aspiration was 98.2 ± 3.5% (range, 92.9-100%). In eight recurrent cases, EA resulted in a significant decrease in volume (P=0.012), as well as in cosmetic (P=0.011) and symptom (P=0.01) scores at last follow-up; however two cases of primary failure of EA was treated by repeat EA. No major complications occurred in any patient. CONCLUSIONS: For symptomatic nonfunctioning PCs, simple aspiration could be a first line procedure for diagnosis and treatment, while EA can be a subsequent treatment modality for recurrent cases.

Radiofrequency ablation of benign thyroid nodules does not affect thyroid function in patients with previous lobectomy.

BACKGROUND: Surgical management of symptomatic benign thyroid nodules in patients with previous lobectomy poses a dilemma for physicians. Radiofrequency (RF) ablation may provide a treatment option that avoids surgery and preserves thyroid function. We evaluated whether RF ablation of benign thyroid nodules affects thyroid function in patients with previous lobectomy. METHODS: A total of 11 patients with 14 thyroid nodules were enrolled using the following criteria: (i) having a predominantly solid nodule; (ii) reporting pressure symptoms or cosmetic problems; (iii) cytological confirmation of benignancy; (iv) no malignant features detected using ultrasound; (v) serum thyroid hormone and thyrotropin (TSH) levels within normal limits; and (vi) refusal of or ineligibility for surgery. Thyroid function, nodule volumes, and clinical concerns were evaluated before RF ablation and during follow-up after RF ablation. RESULTS: The mean follow-up duration after RF ablation was 43.7±30.7 months (range=7-92 months). The mean nodule volume was 9.7 mL (0.9-57.6 mL) before the procedure, and was significantly decreased at the last follow-up (p<0.001) with a mean volume reduction rate of 87.2%. The mean symptom score (p=0.003) and cosmetic score (p=0.003) were both significantly decreased at the last follow-up. Levels of TSH, free thyroxine, and triiodothyronine were not significantly different prior to treatment and at the last follow-up (p>0.05), and remained normal in all patients. CONCLUSIONS: In patients with previous lobectomy, RF ablation should be considered as a first-line treatment for symptomatic benign thyroid nodules to preserve thyroid function.

Radiofrequency ablation (RFA) of benign thyroid nodules in patients with incompletely resolved clinical problems after ethanol ablation (EA).

BACKGROUND: Although ethanol ablation (EA) is effective, refractory cases have been reported in 5-25% of patients, with a marked decline in efficacy on subsequent reattempt. The aim of this study was to evaluate the role of radiofrequency ablation (RFA) after EA of benign thyroid nodules in patients with incompletely resolved initial clinical problems. METHODS: Among 137 patients with 137 benign thyroid nodules who underwent EA, 27 patients (M:F = 5:22; mean age = 38 years, range = 21-60 years) underwent additional RFA if all of the following criteria were fulfilled: (1) complaint of incompletely resolved clinical problems, (2) demonstration of remaining solid component with internal vascularity on 1-month follow-up power Doppler US, and (3) patient desire for additional treatment. After RFA, there was improvement of clinical symptoms and characteristics and volume reduction of the treated nodules as seen on US; complications were evaluated at each follow-up. RESULTS: The mean follow-up duration was 21.2 months (range = 6-38 months) after RFA. The mean symptom grading score of 10-cm visual analog scale, the mean cosmetic grading score on a 4-point scale, and the mean volume reduction of thyroid nodules were all significantly decreased from those seen before RFA (2.4-1.1, 3.7-1.5, and 4.2-1.1, respectively) (P < 0.05). There were no major complications. CONCLUSIONS: RFA is an effective and safe method for treating benign thyroid nodules in patients with incompletely resolved clinical problems following EA.

Benign predominantly solid thyroid nodules: prospective study of efficacy of sonographically guided radiofrequency ablation versus control condition.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of radiofrequency ablation of benign predominantly solid thyroid nodules by comparing the findings in treatment and control groups. SUBJECTS AND METHODS: Thirty patients with normal thyroid function, each with a benign predominantly (> 50%) solid thyroid nodule causing pressure symptoms or cosmetic problems, were assigned to a control group (n = 15) or to a group undergoing a single session of radiofrequency ablation (n = 15). Thyroid nodule volume, thyroid function, pressure symptoms, and cosmetic concerns were evaluated before treatment and during follow-up. Sonographically guided radiofrequency ablation was performed with an internally cooled electrode (1-cm active tip) with an output power of 30-80 W. RESULTS: The control group had no resolution of symptoms or cosmetic problems. The mean nodule volume increased slightly after 6 months but without statistical significance (p = 0.46). In the radiofrequency ablation group, the mean symptom score (p = 0.001) and cosmetic grade (p = 0.001) improved significantly. Mean nodule volume decreased significantly from 7.5 +/- 4.9 mL (range, 1.7-20.0 mL) to 1.3 +/- 0.8 mL (range, 0.2-2.6 mL) 6 months after radiofrequency ablation (p = 0.001). There were no major complications of ablation. CONCLUSION: This study confirmed that radiofrequency ablation is effective for reducing nodule volume and relieving nodule-related clinical problems and that an effect due to spontaneous nodule reduction can be excluded owing to the results of the comparison with a similar control group.

Radiofrequency ablation for the treatment of autonomously functioning thyroid nodules.

BACKGROUND: Some patients with autonomously functioning thyroid nodules (AFTN) are not suitable for surgery or radioiodine therapy. Therefore, minimally invasive alternative treatments, such as ethanol ablation or radiofrequency ablation (RFA), are necessary. METHODS: This study included nine patients (4 toxic and 5 pretoxic patients; male to female ratio = 1:8; mean age, 47 +/- 17 (range, 25-71) years) who were not eligible for surgery or radioiodine therapy. All of the patients showed hot nodule with suppression of normal thyroid gland in (99m)Tc pertechnetate scintigraphy. RFA was performed using a 17- and 18-gauge internally cooled electrode. Nodule volume, thyroid function, scintigraphy, symptom score (visual analogue scale, 0-10 cm), cosmetic grading score (4-point scale), and complications were evaluated before treatment and at 1, 3, and 6 months follow-up. RESULTS: Mean volume of the index nodule was 14.98 +/- 25.53 (range, 0.29-82.29) mL. After RFA it decreased at 1 month (12.01 +/- 25.97 mL, p = 0.015), 3 months (7.27 +/- 15.13 mL, p = 0.011), 6 months (8.27 +/- 21.29 mL, p = 0.008), and the last month (7.57 +/- 19.99 mL, p = 0.008). Initial mean T3, fT4, and TSH were 156.2 +/- 42.1 ng/dL, 1.73 +/- 0.40 ng/dL, and 0.052 +/- 0.087 mU/mL, respectively. A significant improvement of mean T3, fT4, and TSH were observed at last follow-up (T3: 116.8 +/- 20.7 ng/dL, p = 0.015; fT4: 1.37 +/- 0.26 ng/dL, p = 0.036; TSH: 1.454 +/- 1.756 mU/mL, p = 0.012). After ablation, four patients became a cold or normal scan and five remained as a hot nodule. The mean symptom and cosmetic grading score was reduced from 2.4 +/- 1.7 to 0.6 +/- 0.7 (p = 0.011) and from 3.1 +/- 1.2 to 1.4 +/- 1.0 (p = 0.017), respectively. No major complications were encountered. CONCLUSIONS: RFA seems to be effective and safe for the treatment of AFTN.

One-step ethanol ablation of viscous cystic thyroid nodules.

OBJECTIVE: The purpose of this study was to evaluate the efficacy and safety of one-step ethanol ablation in the management of viscous cystic thyroid nodules. MATERIALS AND METHODS: Viscous cystic thyroid nodules are defined as nodules that cannot be aspirated with an 18-gauge needle. Nine euthyroid patients underwent one-step ethanol ablation of benign single compressive viscous cystic thyroid nodules (cystic portion > 90%). The thick content of the nodules was removed with either a 16-gauge needle (n = 8) or an 8.5-French pigtail catheter (n = 1) connected to a suction pump. An injection of 99% sterile ethanol then was administered. After 10 minutes, all of the injected ethanol was withdrawn. Additional treatment was prescribed if the cystic portion of the nodule remained larger than 1 mL. Follow-up sonography was performed 1 and 6 months after treatment. At each follow-up examination, nodule volume, symptom score (centimeter visual analog scale, 0-10), cosmetic grade (grade 1-4), and complications were evaluated. RESULTS: The mean volume of index nodules was 24.4 +/- 20.3 (SD) mL (range, 4.5-57.4 mL). The mean amount of ethanol injected was 11.8 +/- 10.1 mL (range, 2-27 mL). The mean total procedure time was 27.8 +/- 10.4 minutes (range, 15-45 minutes). One month after ablation, the mean volume of the nodules had decreased significantly (7.2 +/- 9.4 vs 24.4 +/- 20.3 mL, p = 0.008). Additional reduction was found at the 6-month follow-up examination, the mean nodule volume being 2.1 +/- 3.8 mL (p = 0.008). The mean volume reductions at 1 and 6 months were 78.4% +/- 14.4% and 93.6% +/- 6.8%. The mean symptom score decreased from 3.2 +/- 1.5 to 0.4 +/- 1.0 (p < 0.05) and the mean cosmetic grade from 3.9 +/- 0.3 to 1.3 +/- 0.7 (p < 0.05). No major complications were encountered. CONCLUSION: One-step ethanol ablation is an effective and safe method of management of viscous cystic thyroid nodules.

Radiofrequency ablation of benign thyroid nodules: safety and imaging follow-up in 236 patients.

This study evaluated the safety and volume reduction of ultrasonography (US)-guided radiofrequency ablation (RFA) for benign thyroid nodules, and the factors affecting the results obtained. A total of 302 benign thyroid nodules in 236 euthyroid patients underwent RFA between June 2002 and January 2005. RFA was carried out using an internally cooled electrode under local anesthesia. The volume-reduction ratio (VRR) was assessed by US and safety was determined by observing the complications during the follow-up period (1-41 months). The correlation between the VRR and several factors (patient age, volume and composition of the index nodule) was evaluated. The volume of index nodules was 0.11-95.61 ml (mean, 6.13 +/- 9.59 ml). After ablation, the volume of index nodules decreased to 0.00-26.07 ml (mean, 1.12 +/- 2.92 ml) and the VRR was 12.52-100% (mean, 84.11 +/- 14.93%) at the last follow-up. A VRR greater than 50% was observed in 91.06% of nodules, and 27.81% of index nodules disappeared. The complications encountered were pain, hematoma and transient voice changes. In conclusion, RFA is a safe modality effective at reducing volume in benign thyroid nodules.