Radiofrequency ablation for an autonomously functioning thyroid nodule

Symptomatic benign thyroid nodules: efficacy of additional radiofrequency ablation treatment session--prospective randomized study

PURPOSE

To prospectively evaluate the efficacy of additional radiofrequency (RF) ablation by comparing the results of one and two sessions.

MATERIALS AND METHODS

All patients gave written informed consent to participate in this institutional review board-approved prospective study. From September 2007 to February 2008, 30 patients with benign predominantly solid thyroid nodules causing pressure symptoms and/or cosmetic problems were randomly assigned to undergo single-session (group 1, n = 15) or two-session (group 2, n = 15) RF ablation. RF ablation was performed by using an 18-gauge internally cooled electrode with ultrasonographic guidance. Nodule volume and cosmetic and symptom scores were evaluated before ablation and at 1, 3, and 6 months after initial ablation, and quantitative comparisons of these were performed by using the Mann-Whitney and Wilcoxon signed rank tests; the Spearman rank test was used for correlation between nodule volume reduction and applied energy.

RESULTS

At 6-month follow-up, there was significant nodule volume reduction, from 13.3 mL ± 12.9 (standard deviation) to 3.8 mL ± 4.4 in group 1 (P = .001), and from 13.0 mL ± 6.8 to 3.0 mL ± 2.2 in group 2 (P = .001). Each group showed significant improvement in cosmetic (P < .0001) and symptom (P = .001) scores. However, there was no significant difference in volume reduction, cosmetic score, and symptom score between two groups (P = .078, P > .99, and P = .259, respectively). In group 1, three of four patients who had a pretreatment nodule volume larger than 20 mL underwent additional RF ablation because of unresolved clinical problems after the first session.

CONCLUSION

Single-session RF ablation showed significant volume reduction and satisfactory clinical response in most patients. Therefore, additional RF ablation should be limited to patients with a large nodule (>20 mL) or unresolved clinical problems.

Radiofrequency ablation of benign thyroid nodules and recurrent thyroid cancers: consensus statement and recommendations

Thermal ablation using radiofrequency is a new, minimally invasive modality employed as an alternative to surgery in patients with benign thyroid nodules and recurrent thyroid cancers. The Task Force Committee of the Korean Society of Thyroid Radiology has developed recommendations for the optimal use of radiofrequency ablation for thyroid nodules. These recommendations are based on a comprehensive analysis of the current literature, the results of multicenter studies, and expert consensus.

Radiofrequency ablation of thyroid nodules: basic principles and clinical application

Radiofrequency (RF) ablation has been gaining popularity as a minimally invasive treatment for benign thyroid nodules regardless of the extent of the solid component. RF ablation of benign nodules demonstrated volume reductions of 33-58% after one month and 51-85% after six months, while solving nodule-related clinical problems. RF ablation has recently shown positive short-term results for locoregional control as well as symptom improvement in patients with recurrent thyroid cancers. This paper reviews the basic physics, indications, patient preparation, devices, procedures, clinical results, and complications of RF ablation.

The efficacy and complications of radiofrequency ablation of thyroid nodules

PURPOSE OF REVIEW

The use of radiofrequency ablation has increased rapidly in recent years and is receiving increased attention as a minimally invasive method to treat benign and malignant thyroid nodules.

RECENT FINDINGS

Radiofrequency ablation has been shown to be an alternative to surgery in the treatment of benign thyroid nodules. Radiofrequency ablation of benign cold nodules showed volume reductions of 32.7-58.2% at 1 month and 50.7-84.8% at 6 months, while reducing symptoms and cosmetic problems. Radiofrequency ablation of autonomously functioning thyroid nodules effectively improves thyroid function and reduces nodule volume. Recently, radiofrequency ablation of recurrent thyroid cancers showed good short-term results for locoregional control of well differentiated thyroid carcinoma in patients at high risk for surgery. Various complications of radiofrequency ablation have been reported, including pain, voice change, hematoma, skin burn at the puncture site, thyrotoxicosis, hypothyroidism, edema, and fever, but most patients recovered spontaneously without sequelae.

SUMMARY

Radiofrequency ablation is an effective and well tolerated treatment option for benign thyroid nodules. Radiofrequency ablation of recurrent thyroid cancers may be an alternative to surgery in patients at high surgical risk.

Locoregional control of metastatic well-differentiated thyroid cancer by ultrasound-guided radiofrequency ablation

OBJECTIVE

The purpose of this study was to evaluate the efficacy and safety of ultrasound-guided radiofrequency ablation (RFA) in the control of metastatic well-differentiated thyroid carcinoma in patients for whom surgery is not feasible.

MATERIALS AND METHODS

Between December 2004 and June 2008, 12 metastatic differentiated thyroid carcinomas (mean diameter, 13.8 mm; range, 4-28 mm) in 10 patients (six women, four men; mean age, 44.8 years) were treated with RFA. The inclusion criteria for RFA were fewer than three metastatic tumors confirmed with ultrasound-guided fine-needle aspiration biopsy, no metastatic tumor beyond the neck at RFA, and infeasibility of surgery. A radiofrequency generator and 18-gauge internally cooled electrodes with a 7-cm shaft length and 0.5- and 1-cm active tips were used depending on the size of the targeted tumors. Ten of the 12 metastatic tumors (83%) were treated in a single session of RFA, and the other two required two sessions. The ablation time ranged from 60 to 900 seconds.

RESULTS

After treatment, the mean largest diameter decreased significantly from 13.8 ± 7.0 mm to 3.3 ± 3.9 mm (p = 0.002), as did mean volume, from 55.5 ± 50.3 mm(3) to 5.7 ± 9.3 mm(3) (p = 0.002). At the last follow-up evaluation, the serum thyroglobulin concentration had decreased in 7 of 10 patients. One patient had dysphonia immediately after RFA of a left surgical bed.

CONCLUSION

Although surgery is the standard treatment of locally metastatic thyroid cancer, RFA is effective for locoregional control of metastatic well-differentiated thyroid carcinoma in patients for whom surgery is infeasible.

Thermal ablation for benign thyroid nodules: radiofrequency and laser

Although ethanol ablation has been successfully used to treat cystic thyroid nodules, this procedure is less effective when the thyroid nodules are solid. Radiofrequency (RF) ablation, a newer procedure used to treat malignant liver tumors, has been valuable in the treatment of benign thyroid nodules regardless of the extent of the solid component. This article reviews the basic physics, techniques, applications, results, and complications of thyroid RF ablation, in comparison to laser ablation.

Clinical significance of vagus nerve variation in radiofrequency ablation of thyroid nodules

OBJECTIVES

To evaluate the types and incidence of vagus nerve variations and to assess factors related to the vulnerability of vagus nerves during the radiofrequency (RF) ablation of thyroid nodules.

METHODS

Bilateral vagus nerves of 304 consecutive patients who underwent ultrasound of the neck were assessed. Two radiologists evaluated vagus nerve type (types 1-4; lateral/anterior/medial/posterior), the shortest distance between the thyroid gland and vagus nerve, and thyroid contour. Vagus nerve vulnerability was defined as a vagus nerve located within 2 mm of the thyroid gland through the ex vivo experiments, and factors associated with vulnerability were assessed.

RESULTS

We were unable to find one vagus nerve. Of the 607 vagus nerves, 467 (76.9%) were type 1, 128 (21.1%) were type 2, 10 (1.6%) were type 3, and 2 (0.3%) were type 4, with 81 (13.3%) being vulnerable. Univariate analysis showed that sex, location, thyroid contour and type were significantly associated with vagus nerve vulnerability. Multivariate analysis showed that bulging contour caused by thyroid nodules (P = 0.001), vagus nerve types 2/4 (P < 0.001) and type 3 (P < 0.001) were independent predictors.

CONCLUSION

The operator should pay attention to anatomical variations and the resulting vagus nerve injury during RF ablation of bulging thyroid nodules.

Optimum first-line treatment technique for benign cystic thyroid nodules: ethanol ablation or radiofrequency ablation?

OBJECTIVE

The purpose of this article is to compare the efficacy and safety of ethanol ablation and radiofrequency ablation (RFA) used as treatment of benign cystic thyroid nodules.

MATERIALS AND METHODS

Fifty-seven patients (44 women and 13 men) with benign cystic nodules (cystic portions > 90%) inducing pressure symptoms or cosmetic problems were treated with ethanol ablation (n = 36) or RFA (n = 21). Ethanol ablation was performed using 16- or 18-gauge needles with 95-99% ethanol, and RFA used a cooled-electrode RFA system and 17- or 18-gauge internally cooled electrodes. Of nine viscous nodules, five were treated with ethanol ablation and four with RFA, with all except for one nodule in the RFA group being treated only after evacuation of internal colloid material. Nodule volume, symptom score (0-10), cosmetic score (1-4), and complications were evaluated before and after treatment.

RESULTS

Both ethanol ablation and RFA resulted in significant decreases in nodule volume (p < 0.001), symptom score (p < 0.001), and cosmetic score (p < 0.001). There were no between-group differences in mean volume reduction (p = 0.15), decreases in symptoms (p = 0.53), cosmetic scores (p = 0.69), or therapeutic success rate (p = 0.61). However, the mean number of treatment sessions was significantly lower in the ethanol ablation than in the RFA group (p = 0.026). No serious complications were encountered in either group.

CONCLUSION

Ethanol ablation yielded similar results with fewer treatment sessions compared with RFA. Because ethanol ablation is also less expensive and simpler to perform than RFA, our findings suggest that ethanol ablation, rather than RFA, should be the first-line treatment technique for benign predominantly cystic thyroid nodules.

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.

Minimally invasive ablation of a toxic thyroid nodule by high-intensity focused ultrasound

HIFU is used in the treatment of cancer (prostate, breast) and uterine fibroma but not yet in TNs. This case report describes the first successful ablation of a toxic TN with HIFU. TSH and radioiodine scan normalization were achieved without complications and maintained for 18 months. HIFU treatment is a minimally invasive technique that may be an effective safe alternative to radioiodine or surgery in patients with toxic TNs.