Thermal ablation of thyroid nodules: are radiofrequency ablation, microwave ablation and high intensity focused ultrasound equally safe and effective methods?

OBJECTIVES: This study compares volume reduction of benign thyroid nodules three months after Radiofrequency Ablation (RFA), Microwave Ablation (MWA) or High Intensity Focused Ultrasound (HIFU) to evaluate which of these methods is the most effective and safe alternative to thyroidectomy or radioiodine therapy. MATERIAL AND METHODS: Ninety-four patients (39 male, 55 female) with a total of 118 benign, symptomatic thyroid nodules were divided into three subgroups. HIFU was applied to 14 patients with small nodules. The other 80 patients were divided up into two groups of 40 patients each for RFA and MWA in the assumption that both methods are comparable effective. The pre-ablative and post-ablative volume was measured by ultrasound. RESULTS: RFA showed a significant volume reduction of nodules of 50 % (p<0.05), MWA of 44 % (p<0.05) and HIFU of 48 % (p<0.05) three months after ablation. None of the examined ablation techniques caused serious or permanent complications. CONCLUSION: RFA, MWA and HIFU showed comparable results considering volume reduction. All methods are safe and effective treatments of benign thyroid nodules. KEY POINTS: • Thermal Ablation can be used to treat benign thyroid nodules • Thermal Ablation can be an alternative to thyroidectomy or radioiodine therapy • Radiofrequency Ablation, Microwave Ablation, High Intensity Focused Ultrasound are safe and effective.

Comparison between microwave ablation and bipolar radiofrequency ablation in benign thyroid nodules: differences in energy transmission, duration of application and applied shots.

PURPOSE: Comparison between different thermal ablation systems for thyroid nodules regarding their different procedural characteristics such as treatment-time, number of shots and energy transmission in the context of their clinical performance such as complication rate and volume reduction after three months. METHODS: A total of 60 patients with 65 nodules underwent thermal ablation of thyroid nodules with either microwave ablation (MWA) (9 male, 15 female and mean age 57 ± 13 years) or radiofrequency ablation (RFA) (12 male, 24 female and mean age 54 ± 12 years). RESULTS: Mean initial volume (MWA: 23.90 ± 17.35 ml; RFA: 29.44 ± 30.09 ml), energy transmission (MWA: 13.56 ± 10.17 kJ; RFA: 15.12 ± 13.45 kJ), energy transmission per ml (MWA: 0.85 ± 1.01 kJ/ml; RFA: 0.65 ± 0.32 kJ/ml), power (MWA: 22.69 ± 12.32 J/s; RFA: 20.97 ± 7.86 J/s) and duration of ablation (MWA: 618 ± 304 s; RFA: 695 ± 463 s) were not statistically different (p > .05). MWA required significantly less shots (MWA: 3 ± 1; RFA: 6 ± 3) than RFA (p < .05). At three-months follow-up a significant mean nodular volume reduction of 53.54 ± 15.40% after MWA and 51.21 ± 16.58% after RFA (p < .05) was measured. However, mean nodular volume reduction was not significantly different between both systems (p > .05). One patient treated by MWA reported a transient Horner's syndrome, which recovered without any further treatment. Major complications such as nodule rupture, infection or persisting nerve injuries did not occur. CONCLUSION: Both systems are suitable to treat thyroid nodules and show no significant difference in the duration of application, energy transmission and volume reduction. However, MWA requires less shots to treat the whole nodule.

Minimally invasive local ablative therapies in combination with radioiodine therapy in benign thyroid disease: preparation, feasibility and efficiency - preliminary results.

PURPOSE: Initial studies of combinations of radioiodine therapy (RIT) and local ablative procedures for the treatment of thyroid nodules have shown promising results. The goal of this study was to evaluate the effectiveness of RIT combined with radiofrequency ablation (RFA) in patients with goitres and to determine which ablative procedure is the most suitable for a combined therapy. METHODS: Thirty patients with goitres were divided into two subgroups. A test group of 15 patients received combined therapy (RIT + RFA) and a control group of 15 patients received RIT mono therapy. All patients underwent assessments including ultrasound, laboratory evaluation (T3, T4, TSH, TG, TPOAb, TgAbTRAb) and scintigraphic imaging with Tc-99m-Pertechnetate. The 3-month volume reduction was used to evaluate therapy effectiveness. RESULTS: Combined therapy (subgroup 1) resulted in a significant (p < 0.05) thyroid volume reduction (22.3 ± 54 ml/32.2 ± 58.2%) with better performance (p > 0.05) than the control group (20.2 ± 32.2 ml/29.6 ± 42.1%). All patients became euthyroid after treatment. No major discomfort or complications occurred. A review of the literature investigating combinations of other local ablative procedures with RIT was performed to determine the most promising combination. CONCLUSIONS: The present study confirms the positive experiences with the combined therapy of RIT and local ablative procedures shown in the current literature and approves this approach for the treatment of goitres with RFA + RIT. These findings, when confirmed by further studies, should expand the indication of combined therapy as a minimally invasive alternative to surgery.

Comparison of Mono- and Bipolar Radiofrequency Ablation in Benign Thyroid Disease.

PURPOSE: Radiofrequency ablation (RFA) is an approved minimal invasive method for the treatment of benign thyroid nodules. Several experimental, mainly ex vivo animal studies have compared the effectiveness of different RFA procedures in liver tissue. The aim of this retrospective clinical study was to evaluate the difference between monopolar and bipolar RFA in thyroid tissue considering thyroid volume reduction, patient discomfort and ultrasound evaluation. METHODS: Eighteen patients with symptomatic complex benign thyroid nodules were treated in a single RFA session. Nine patients were treated with monopolar RFA, and nine other patients were treated with bipolar RFA. All patients underwent assessments before therapy and at 3-month follow-up (3MFU) including a complete hormone status (T3, T4, TSH, TG, TPOAb, TgAb, TRAb) and several ultrasound (US) evaluations using B-mode and color-coded Doppler imaging. The US evaluations contained measurement of volume, US Doppler, US echogenicity and US elastography. Additionally, applied energy (kJ), power output (W), number of shots (N) and total treatment time (s) were recorded in every case. RESULTS: Monopolar RFA resulted in a significant (p < 0.05) average thyroid volume reduction of Ø 18 ± 77 ml (25.1 ± 103%) and a nodule volume reduction of Ø 10.6 ± 22 ml (60.3 ± 62%). Bipolar RFA resulted in a significant (p < 0.05) average thyroid volume reduction of Ø 21.2 ± 54 ml (43.2 ± 84%) and a nodule volume reduction of Ø 13.8 ± 33 ml (70.8 ± 46%). Both groups showed equal results concerning volume reduction (p > 0.05). Monopolar RFA did not lead to any significant changes concerning the US scores, whereas bipolar RFA led to a significant (p < 0.05) reduction in US Doppler and nodular blood flow. No significant difference between both groups could be found concerning applied energy, treatment time, power output and number of shots (p > 0.05). CONCLUSION: Bipolar RFA did not show any disadvantages in comparison with monopolar RFA in the treatment of benign thyroid nodules. It shows better performance in terms of volume reduction and is superior when it comes to feasibility and patient discomfort. The recent study confirms the good ex vivo results for bipolar RFA.

Bipolar radiofrequency ablation of benign thyroid nodules using a multiple overlapping shot technique in a 3-month follow-up.

Purpose The aim of this study was to evaluate the decrease of benign thyroid nodules after bipolar radiofrequency ablation (RFA) in a 3-month follow-up using a multiple overlapping shot technique ('MOST'). Methods A total of 18 patients with 20 symptomatic benign thyroid nodules (17 cold nodules, 3 hyperfunctioning nodules) were treated in one single session by bipolar RFA. Bipolar ablation was performed using MOST. The nodule volumes were measured prior to ablation and 3 months after the procedure using ultrasound. The population consisted of either solid (>80% solid tissue within the volume of interest), complex, or cystic nodules (<20% solid tissue within the volume of interest). Results Bipolar RFA resulted in a highly significant (p < 0.0001) decrease of nodule volume (ΔV), median 5.3 mL (range 0.13-43.1 mL), corresponding to a relative reduction in mean of 56 ± 17.9%. Median initial volume was 8 mL (range 0.48-62 mL); 3 months after ablation a median volume of 2.3 mL (range 0.3-32 mL) was measured. Nodule growth ≥50% occurred in 70% (14 nodules). At the follow-up no complications such as infections, persisting pain, nerve injuries or immunogen stimulation occurred. Patients with cold nodules (15) remained euthyroid, with hyperfunctioning nodules either euthyroid (2) or latent hypofunctional (1). Conclusion The use of bipolar RFA is an effective, safe and suitable thermoablative technique to treat benign thyroid nodules. Combined with the multiple overlapping shot technique it allows sufficient ablation.

Carcinoembryonic antigen-related cell adhesion molecule 1 inhibits MMP-9-mediated blood-brain-barrier breakdown in a mouse model for ischemic stroke.

RATIONALE: Blood-brain-barrier (BBB) breakdown and cerebral edema result from postischemic inflammation and contribute to mortality and morbidity after ischemic stroke. A functional role for the carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in the regulation of reperfusion injury has not yet been demonstrated. OBJECTIVE: We sought to identify and characterize the relevance of CEACAM1-expressing inflammatory cells in BBB breakdown and outcome after ischemic stroke in Ceacam1(-/-) and wild-type mice. METHODS AND RESULTS: Focal ischemia was induced by temporary occlusion of the middle cerebral artery with a microfilament. Using MRI and Evans blue permeability assays, we observed increased stroke volumes, BBB breakdown and edema formation, reduction of cerebral perfusion, and brain atrophy in Ceacam1(-/-) mice. This translated into poor performance in neurological scoring and high poststroke-associated mortality. Elevated neutrophil influx, hyperproduction, and release of neutrophil-related matrix metalloproteinase-9 in Ceacam1(-/-) mice were confirmed by immune fluorescence, flow cytometry, zymography, and stimulation of neutrophils. Importantly, neutralization of matrix metalloproteinase-9 activity in Ceacam1(-/-) mice was sufficient to alleviate stroke sizes and improve survival to the level of CEACAM1-competent animals. Immune histochemistry of murine and human poststroke autoptic brains congruently identified abundance of CEACAM1(+)matrix metalloproteinase-9(+) neutrophils in the ischemic hemispheres. CONCLUSIONS: CEACAM1 controls matrix metalloproteinase-9 secretion by neutrophils in postischemic inflammation at the BBB after stroke. We propose CEACAM1 as an important inhibitory regulator of neutrophil-mediated tissue damage and BBB breakdown in focal cerebral ischemia.

Further Investigation on High-intensity Focused Ultrasound (HIFU) Treatment for Thyroid Nodules: Effectiveness Related to Baseline Volumes.

RATIONALE AND OBJECTIVES: Several minimally invasive thermal techniques have been developed for the treatment of benign thyroid nodules. A new technique for this indication is high-intensity focused ultrasound (HIFU). The aim of this study was to assess effectiveness in varying preablative nodule volumes and whether outcome patterns that were reported during studies with other thermal ablative procedures for thyroid nodule ablation would also apply to HIFU. MATERIALS AND METHODS: Over the last 2 years, 19 nodules in 15 patients (12 women) whose average age was 58.7 years (36-80) were treated with HIFU in an ambulatory setting. Patients with more than one nodule were treated in multiple sessions on the same day. The mean nodule volume was 2.56 mL (range 0.13-7.67 mL). The therapeutic ultrasound probe (Echopulse THC900888-H) used in this series functions with a frequency of 3 MHz, reaching temperatures of approximately 80°C-90°C and delivering an energy ranging from 87.6 to 320.3 J per sonication. To assess the effectiveness of thermal ablation, nodular volume was measured at baseline and at 3-month follow-up. The end point of the study was the volume reduction assessment after 3 months' follow-up. Therapeutic success was defined as volume reduction of more than 50% compared to baseline. This study was retrospectively analyzed using the Wilcoxon signed rank test and Kendall tau. RESULTS: The median percentage volume reduction of all 19 nodules after 3 months was 58%. An inverse correlation between preablative nodular volume and percentage volume shrinking was found (tau = -0.46, P < .05). Therapeutic success was achieved in 10 out of 19 patients (53%). CONCLUSIONS: HIFU of benign thyroid nodules can be carried out as an alternative therapy for nodules ≤3 mL if patients are refusing surgery or radioiodine therapy.

Comparative study evaluating the efficiency of cooled and uncooled single-treatment MWA in thyroid nodules after a 3-month follow up.

OBJECTIVE: The aim of this study was to evaluate and compare the efficacy of single-treatment cooled and uncooled microwave ablation in thyroid nodules. METHODS: Eighteen patients (11 women) with an average age of 62 years (range: 41-80) with 18 cold, mainly solid or solid thyroid nodules were treated with cooled or uncooled microwave ablation. Pain during the treatment was measured on a 10-point score. Side effects revealed by ultrasound or patients' complaints were documented. Laboratory data was evaluated before, 24 h and three months after MWA. Nodule volumes were measured before and three months after MWA. RESULTS: Cooled MWA was better tolerated than uncooled MWA. A significant reduction of thyroid nodule volume was observed in all cases. The reduction after cMWA was higher (40%) than after uMWA (29%). Pain intensity during cMWA was significantly lower than after uMWA. CMWA and uMWA led to a significant decrease of nodule blood circulation and echogenicity and to a significant increase of nodule elasticity. Thyroid function remained intact in all cases. The energy (kJ/s) administered into the nodules in relation to the ablation time during cMWA was higher than during uMWA. CONCLUSIONS: CMWA leads to a slightly higher but statistically not significant nodule volume reduction than uMWA. Patient comfort during cMWA is higher than during uMWA. The risk of unintended side effects is less in cMWA. A Single-treatment provides sufficient results.

Cooled microwave ablation of thyroid nodules: Initial experience.

OBJECTIVE: To evaluate if internally cooled microwave ablation (cMWA) is a safe and effective method for treatment of benign and malign thyroid nodules. METHODS: 9 patients with 11 symptomatic cold benign thyroid nodules and 1 recurrent thyroid carcinoma ranging in volume from 9.1 to 197ml (mean size 52±â€Š57ml) were treated with cMWA. The mean age of the patients was 59 years. Pain during the treatment was measured on a 10-point scale. Side effects revealed by ultrasound or patients' complaints were documented. Periablative efficacy was measured 24h after cMWA as change (Δ) in serum thyreoglobulin (Tg). Nodule elasticity was measured on a 4-point scale, blood circulation and echogenicity on a 3-point scale. RESULTS: All patients tolerated cMWA well. Median pain intensity averaged 2.1±0.8 (range: 1-3). Postablative hematoma was observed in all cases. In no cases ablation led to hoarseness, superficial burns, nodule ruptures, vagal reactions or dysphagia. cMWA lead to a significant decrease of blood circulation, nodule echogenicity and a significant increase of elasticity (Δ = 1.1 ±â€Š0.33; 0.8 ±â€Š0.4 and 1.1 ±â€Š0.6 points)(p<0.05). An average increase of 4495ng/ml Tg was measured (p<0.05). CONCLUSIONS: cMWA is an effective and secure method for treatment of thyroid nodules.