Percutaneous Laser Ablation in the Treatment of Toxic and Pretoxic Nodular Goiter

Radioiodine versus radiofrequency ablation to treat autonomously functioning thyroid nodules: a systematic review and comparative meta-analysis

PURPOSE

Radioiodine (RAI) is a well-established first-line therapy for autonomously functioning thyroid nodules (AFTN). Radiofrequency ablation (RFA) is a minimally invasive procedure that has been proposed as an alternative treatment option for hyperthyroidism caused by AFTN. Although RFA has been shown to be useful for reducing nodule volume and improving TSH levels in AFTN, no comprehensive comparative clinical studies have been proposed to evaluate the overall response to RFA treatment. The aim of this comparative systematic review and meta-analysis was to evaluate the response of RAI and RFA treatments in AFTN.

METHODS

A systematic search strategy was applied in PubMed, Web of Science, Scopus, Cochrane Library, and ClinicalTrials.gov until July 2023 without time or language restrictions. Studies investigating the response to RAI and/or RFA treatment in AFTN patients 6 and/or 12 months after treatment were included. The risk of bias was assessed based on the study design. Random-effect models were used for the meta-analysis.

RESULTS

Twenty-three articles (28 reports) met the inclusion criteria and were included in the study. Overall, RAI therapy was found to have a significantly higher treatment response (94%) than RFA (59%), although the volume of AFTNs was reduced to a similar extent. In the direct comparison (n = 3 studies), RFA showed a higher risk of non-response than RAI (RR, 1.24; 95% CI, 0.94-1.63; z = 1.55; p = 0.12).

CONCLUSIONS

Our results demonstrate the superiority of RAI over RFA in terms of success rates and safety profile and confirm RAI as the first choice for the treatment of AFTNs.

Efficacy and Safety of Radiofrequency Ablation for the Treatment of Autonomously Functioning Thyroid Nodules: A Long-Term Prospective Study

Objective

This study aims to evaluate the efficacy and safety of RFA in the AFTN treatment after 2 years of follow-up and to find the factors related to treatment responses through TSH level and VRR.

Materials and Methods

This long-term prospective study was conducted from September 2017 to April 2021 on 17 AFTNs treated with RFA. Clinical evaluations, thyroid function tests, thyroid scintigraphy, and ultrasonography examinations were performed at 1 month, 3 months, 6 months, and 24 months after ablation. The primary endpoint was the success rate of RFA in restoring the euthyroidism stage after 24 months of follow-ups; secondary outcomes were VRR and improvements of US parameters, clinical examinations, and complications. The Spearman rank correlation test was used to determine related factors with treatment response variables.

Results

At the 24 months after the procedure, symptom score, cosmetic score, vascularity grade, and nodule volume significantly decreased. The VRR reduced approximately 42.77%, 63.13%, 78.3%, and 95.65% after 1 month, 3 months, 6 months, and 24 months follow-up. All 17 patients were restored euthyroid state without taking ATDs. No major complications were collected. The last TSH level was significantly correlated with the age of patients (Spearman rho = −0.637, p = 0.008). The VRR was significantly correlated with age of patients (Spearman rho = 0.566, p = 0.018) and initial TSH (Spearman rho = 0.485, p = 0.048).

Conclusion

RFA was demonstrated as a safe and effective option for AFTN treatment in long-term follow-up. It can be used as an alternative treatment with encouraging results.

Efficacy and safety of thermal ablation for autonomously functioning thyroid nodules: a systematic review and meta-analysis

BACKGROUND

Although thermal ablation has been regarded as an alternative treatment option for autonomously functioning thyroid nodules (AFTNs), the efficacy of this treatment in patients with AFTNs has not yet been systematically evaluated. In this systematic review and meta-analysis, we aimed to evaluate the efficacy and safety of thermal ablation in the treatment of AFTN, and identify the factors affecting the effectiveness of the treatment.

METHODS

Ovid-MEDLINE and Embase databases were searched for studies reporting the efficacy and safety of thermal ablation for patients with AFTN published up until January 6, 2020. Data extraction and quality assessment were performed by two radiologists according to PRISMA guidelines. The primary and secondary outcomes were to yield the pooled proportions of thyroid-stimulating hormone (TSH) normalization and pooled estimates of volume reduction rate (VRR), respectively. Subgroup analyses were performed to identify factors affecting the treatment efficacy.

RESULTS

This systematic review identified 411 AFTNs treated by thermal ablation in 391 patients in 14 studies. TSH normalization was achieved in 71.2% of patients and the volume reduction rate was 69.4% at a mean follow-up period of 12.8 months. No patients experienced hypothyroidism or a life-threatening complication during follow-up. Subgroup analyses according to nodule volume did not find a significant difference in TSH normalization (p = 0.54) or VRR (p = 0.94).

CONCLUSIONS

Thermal ablation is an effective and safe treatment method for patients with AFTNs. The nodule volume did not affect the efficacy of thermal ablation, and this result should be considered in future thermal ablation guidelines.

KEY POINTS

• Thermal ablation has good efficacy and safety in the treatment of autonomously functioning thyroid nodule. • The efficacy of thermal ablation was not affected by nodule volume.

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.

Efficacy of radiofrequency ablation in autonomous functioning thyroid nodules. A systematic review and meta-analysis

Whether thermal ablation is effective to treat toxic thyroid nodules (TTN) is still unknown. Aim of this review was to achieve more robust evidence on the efficacy of radiofrequency ablation (RFA) in treating TTN in terms of TSH normalization, thyroid scintiscan, and volume reduction rate (VRR). A comprehensive literature search of PubMed/Medline and Scopus was performed in November 2018 to retrieve published studies. Original papers reporting TTN treated by RFA and later followed-up were eligible. Excluded were: articles not within this field, articles with unclear data, overlapping series, case/series reports. Discordances were solved in a final collegial meeting. Information was collected concerning population features, treatment procedure, follow-up, cases with TSH normalization, cases with scintiscan normalization, VRR of nodules. Pooled prevalence of patients with TSH or scintiscan normalization, and pooled VRR over time were calculated. For statistical analysis, the random-effects model was used. Eight articles published between 2008 and 2018 were included. The overall number of AFTN treated by RFA was 205. Five studies used a single session of treatment. The time of follow-up ranged from six to 24 months. The pooled rate of patients with TSH normalization was 57%. The pooled rate of patients with scintigraphically proven optimal response was 60%. The pooled VRR at 1 year was 79%. Baseline nodules volume was associated with the rate of TSH normalization. In conclusion, a moderate efficacy of RFA in treating TTN was found, and this can represent a solid starting point in this field.

Interventional radiology of the thyroid gland: critical review and state of the art

Thyroid nodules are a common incidental finding during a routinely ultrasound (US) exam unrelated to the thyroid gland in the healthy adult population with a prevalence of 20-76%. As treated before with surgery, in the last years new minimally invasive techniques have been developed as an alternative to surgery. The aim of this review, based on newly revised guidelines, is to provide some information regarding the basic principles, indications, materials, techniques, and results of mini-invasive procedures or treatments for thyroid nodules. We performed a narrative review including both newest and representative papers and guidelines based on the different procedures of ablation techniques developed in the last years for the diagnosis and the treatment of thyroid nodules. All examined papers referred very good results in term of volume nodule reduction, improvement in related symptoms and cosmetic problems, with a very low rate of complications and side effects for all the minimally invasive technique analyzed. Obviously, some differents between technique based on different kind of thyroid nodules and different indication were found. In conclusion, many thyroid nodules nowadays could be treated thanks to the advent of new mini-invasive technique that are less expensive and present a lower risk of major complications and side effects compared to surgery.

A single session of laser ablation for toxic thyroid nodules: three-year follow-up results

PURPOSE

To confirm the effectiveness of laser ablation on toxic nodules in a large population with three years of follow-up.

MATERIAL AND METHODS

Between 2009 and 2014, we treated 82 patients with hyperthyroidism related to the presence of a toxic nodular goitre. Patients were pre-treated pharmacologically with methimazole prior to single session of laser ablation (LA) and then followed up every 3 months with FT4 and TSH blood tests as well as ultrasound examination of the nodules treated.

RESULTS

All patients responded to the treatment. The median nodule volume decreased from 12 ml (range 5-118 ml) to 5 ml (range 1.2-40 ml) after three years (p < 0.001). The percentage of patients who discontinued methimazole therapy was reduced by increasing the initial volume of the toxic nodule. In nodules with a volume less than 5 ml, all patients were able to suspend methimazole; this percentage was reduced to 90.2% in nodules with a volume between 5 and 15 ml, 61.1% in those with volume 15-25 ml and only 28.5% in nodules larger than 25 ml. We had no major complications but only moderate pain and fever in the evening, a few hours after ablation therapy in 10% of treated patients.

CONCLUSIONS

Single session of LA of toxic thyroid nodules is effective and safe, especially in nodules with a volume under 15 ml.

Nodule size as predictive factor of efficacy of radiofrequency ablation in treating autonomously functioning thyroid nodules

CONTEXT

No defined pre-treatment factors are able to predict the response to radiofrequency ablation (RFA) of an autonomously functioning thyroid nodule (AFTN).

OBJECTIVE

Primary endpoint was to evaluate the success rate of RFA to restore euthyroidism in a cohort of adult patients with small solitary AFTN compared with medium-sized nodules. Secondary endpoints included nodule volume reduction and rate of conversion from hot nodules to cold using scintiscan.

METHODS

This was a 24-month prospective monocentric open parallel-group trial. Twenty-nine patients with AFTN were divided into two groups based on thyroid volume: 15 patients with small nodules (<12 mL) in group A and 14 patients with medium nodules (>12 mL) in group B. All patients underwent a single session of RFA and were clinically, biochemically, and morphologically evaluated at baseline and at 1, 6, 12 and 24 months after treatment.

RESULTS

After RFA, there was greater nodule volume reduction in group A compared with group B (p < 0.001 for each follow-up point). In group A, there was a greater increase in TSH levels than in group B at 6 (p = 0.01), 12 (p = 0.005), and 24 months (p < 0.001). At 24 months, the rate of responders was greater in group A than in group B (86 vs. 45%; p < 0.001). In group A, 86% of nodules converted from hot to cold compared with 18% in group B (p < 0.001).

CONCLUSIONS

A single session of RFA was effective in restoring euthyroidism in patients with small AFTNs. Nodule volume seems to be a significant predictive factor of the efficacy of RFA in treating AFTN.

Percutaneous laser ablation for benign thyroid nodules: a meta-analysis

Purpose

To evaluate percutaneous laser ablation in treating benign thyroid nodules, we conducted a meta-analysis based on summarizing existing researches.

Materials and Methods

A literature search for clinical trial was performed in PubMed, Cochrane Library and Excerpt Medica Database. The qualities of included studies were evaluated. We calculated the indexes with mean difference. Heterogeneity and publication bias were tested and explored. We performed subgroup analyses and sensitivity analysis further.

Results

A total of 19 researches and 2137 patients were included in this meta-analysis. The pooled estimates of nodule volume were statistically significant after percutaneous laser ablation for 1 month, 3 month, 6month, 12month, 24month and 36month(P < 0.05). The pooled estimate of thyroid-stimulating hormone was statistically significant after percutaneous laser ablation for 1 and 12 month (P = 0.008 and P = 0.03). The pooled estimate of free triiodothyronine was no statistically significant after percutaneous laser ablation for all follow-up intervals. The pooled estimate of free tetraiodothyronin was statistically significant after percutaneous laser ablation1 month (P = 0.004). The pooled estimate of thyroglobulin was statistically significant after percutaneous laser ablation 24 month (P = 0.04). The heterogeneity was found and the source of heterogeneity was explored in nodule volume for 6 and 12 month. No publication bias was found.

Conclusions

This meta-analysis demonstrated that percutaneous laser ablation was safe and useful in shrinking benign thyroid nodules volume, improving thyroid function, relieving symptoms of pressure and esthetic, especial for hyper-vascular benign thyroid nodules. Larger number of high-quality prospective studies still needs to be performed.

Laser, radiofrequency, and ethanol ablation for the management of thyroid nodules

PURPOSE OF REVIEW

The majority of benign thyroid nodules are nearly asymptomatic, remain stable in size, and do not require treatment. However, a minority of patients with growing nodules may complain of local symptoms or have cosmetic concerns, and thus seek surgical consultation.

RECENT FINDINGS

The timely use of ultrasound-guided minimally invasive procedures can change the natural history of benign enlarging thyroid nodules. The procedures produce persistent shrinkage of thyroid nodules and are associated with improvement of local symptoms. Among the various procedures, percutaneous ethanol injection represents the first-line treatment for relapsing thyroid cysts. In solid nonfunctioning nodules, laser and radiofrequency ablation produces a more than 50% reduction in nodular volume that remains persistent over several years. For hyperfunctioning nodules, thermal ablation techniques are not appropriate unless radioactive iodine is contraindicated or not accessible.

SUMMARY

MITs are best suited for the management of medium or large-sized nodules that are sonographically well visualized. Conversely, large nodules or nodular goiters that extend into the chest are difficult to treat. MITs are performed in outpatient clinics, are less expensive, and have a lower risk of complications, compared to surgery, and usually do not induce thyroid dysfunction. However, malignancy should be ruled out with a dedicated ultrasound neck assessment and repeat fine needle aspiration of the lesion before treatment.

Treatment of Metastatic Lymph Nodes in the Neck from Papillary Thyroid Carcinoma with Percutaneous Laser Ablation

PURPOSE

To assess the effectiveness of percutaneous laser ablation (PLA) of cervical lymph node metastases from papillary thyroid carcinoma.

MATERIALS AND METHODS

24 patients (62.3 ± 13.2 year; range 32-80) previously treated with thyroidectomy, neck dissection, and radioiodine ablation underwent ultrasound-guided PLA of 46 (18)FDG-PET/CT-positive metachronous nodal metastases. All patients were at high surgical risk or refused surgery and were unsuitable for additional radioiodine ablation. A 300 µm quartz fiber and a continuous-wave Nd-YAG laser operating at 1.064 mm were used. Technical success, rate of complications, rate of serological conversion, and local control at follow-up were derived. Fisher's exact test and Mann-Whitney U test were used and Kaplan-Meier curve calculated.

RESULTS

Technical success was obtained in all 46 lymph nodes (100 %). There were no major complications. Thyroglobulin levels decreased from 8.40 ± 9.25 ng/ml before treatment to 2.73 ± 4.0 ng/ml after treatment (p = 0.011), with serological conversion in 11/24 (45.8 %) patients. Overall, local control was obtained in 40/46 (86.9 %) lymph nodes over 30 ± 11 month follow-up, with no residual disease seen at imaging in 19/24 (79.1 %) patients. Local control was achieved in 40/46 (86.9 %) lymph nodes at 1 year and in all of the 25 nodes (100 %) followed for 3 years. Estimated mean time to progression was 38.6 ± 2.7 m.

CONCLUSION

Ultrasound-guided PLA is a feasible, safe, and effective therapy for the treatment of cervical lymph node metastases from papillary thyroid carcinoma.

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.

Animal models of disease: feline hyperthyroidism: an animal model for toxic nodular goiter

Since first discovered just 35 years ago, the incidence of spontaneous feline hyperthyroidism has increased dramatically to the extent that it is now one of the most common disorders seen in middle-aged to senior domestic cats. Hyperthyroid cat goiters contain single or multiple autonomously (i.e. TSH-independent) functioning and growing thyroid nodules. Thus, hyperthyroidism in cats is clinically and histologically similar to toxic nodular goiter in humans. The disease in cats is mechanistically different from Graves' disease, because neither the hyperfunction nor growth of these nodules depends on extrathyroidal circulating stimulators. The basic lesion appears to be an excessive intrinsic growth capacity of some thyroid cells, but iodine deficiency, other nutritional goitrogens, or environmental disruptors may play a role in the disease pathogenesis. Clinical features of feline toxic nodular goiter include one or more palpable thyroid nodules, together with signs of hyperthyroidism (e.g. weight loss despite an increased appetite). Diagnosis of feline hyperthyroidism is confirmed by finding the increased serum concentrations of thyroxine and triiodothyronine, undetectable serum TSH concentrations, or increased thyroid uptake of radioiodine. Thyroid scintigraphy demonstrates a heterogeneous pattern of increased radionuclide uptake, most commonly into both thyroid lobes. Treatment options for toxic nodular goiter in cats are similar to that used in humans and include surgical thyroidectomy, radioiodine, and antithyroid drugs. Most authorities agree that ablative therapy with radioiodine is the treatment of choice for most cats with toxic nodular goiter, because the animals are older, and the disease will never go into remission.

Long-term efficacy of ultrasound-guided laser ablation for benign solid thyroid nodules. Results of a three-year multicenter prospective randomized trial

BACKGROUND

The aim of the present trial on ultrasound (US)-guided laser ablation therapy (LAT) of solid thyroid nodules is to assess long-term clinical efficacy, side effects, and predictability of outcomes in different centers operating with the same procedure.

PATIENTS

Two hundred consecutive patients were randomly assigned to a single LAT session (group 1, 101 cases) or to follow-up (group 2, 99 cases) at four thyroid referral centers. Entry criteria were: solid thyroid nodule with volume of 6-17 mL, repeat benign cytological findings, normal thyroid function, no autoimmunity, and no thyroid gland treatment.

METHODS

Group 1: LAT was performed in a single session with two optical fibers, a 1064 nm Nd-YAG laser source, and an output power of 3 W. Volume and local symptom changes were evaluated 1, 6, 12, 24, and 36 months after LAT. Side effects and tolerability of treatment were registered. Group 2: Follow-up with no treatment.

RESULTS

One patient was lost to follow-up in each group. Group 1: Volume decrease after LAT was -49 ± 22%, -59 ± 22%, -60 ± 24%, and -57 ± 25% at 6, 12, 24, and 36 months, respectively (P < .001 vs baseline). LAT resulted in a nodule reduction of >50% in 67.3% of cases (P < .001). Local symptoms decreased from 38 to 8% of cases (P = .002) and cosmetic signs from 72 to 16% of cases (P = .001). Baseline size, presence of goiter (P = .55), or US findings (fluid component ≤ 20% [P = .84], halo [P = .46], vascularization [P = .98], and calcifications [P = .06]) were not predictive factors of a volume decrease > 50%. The procedure was well tolerated in most (92%) cases. No changes in thyroid function or autoimmunity were observed. In group 2, nodule volume increased at 36 months (25 ± 42%; P = .04). The efficacy and tolerability of the procedure were similar in different centers.

CONCLUSIONS

A single LAT treatment of solid nodules results in significant and persistent volume reduction and local symptom improvement, in the absence of thyroid function changes.

The advent of ultrasound-guided ablation techniques in nodular thyroid disease: towards a patient-tailored approach

Surgery is the long-established therapeutic option for benign thyroid nodules, which steadily grow and become symptomatic. The cost of thyroid surgery, the risk of temporary or permanent complications, and the effect on quality of life, however, remain relevant concerns. Therefore, various minimally invasive treatments, directed towards office-based management of symptomatic nodules, without requiring general anaesthesia, and with negligible damage to the skin and cervical tissues, have been proposed during the past two decades. Today, ultrasound-guided percutaneous ethanol injection and thermal ablation with laser or radiofrequency have been thoroughly evaluated, and are accessible procedures in specialized centres. In clinical practice, relapsing thyroid cysts are effectively managed with percutaneous ethanol injection treatment, which should be considered therapy of choice. In solid non-functioning thyroid nodules that grow or become symptomatic, trained operators may safely induce, with a single session of laser ablation treatment or radiofrequency ablation, a 50% volume decrease and, in parallel, improve local symptoms. In contrast, hyperfunctioning nodules remain best treated with radioactive iodine, which results in a better control of hyperthyroidism, also in the long-term, and fewer side-effects. Currently, minimally invasive treatment is also investigated for achieving local control of small size neck recurrences of papillary thyroid carcinoma in patients who are poor candidates for repeat cervical lymph node dissection. This particular use should still be considered experimental.

Microwave ablation of benign thyroid nodules

ABSTRACT: 

Microwave ablation (MWA) has become increasingly popular as a minimally invasive treatment for benign and malignant tumors of the liver, lung and kidney. Recently, two studies have attempted to apply the technique to debulk benign thyroid nodules and gained positive results. MWA of benign nodules demonstrated significant volume reductions, while solving nodule-related clinical problems. This article reviews the basic physics, therapeutic indications, patient preparation, devices, procedures, clinical results and complications of thyroid MWA.

Diagnosis of endocrine disease: thyroid ultrasound (US) and US-assisted procedures: from the shadows into an array of applications

In patients with thyroid nodules, ultrasound (US) imaging represents an indispensable tool for assessment of the risk of malignancy. Over approximately four decades, innovative technology and successive improvements have facilitated its entry into the routine management and greatly improved its predictive value. When US features cannot reliably rule out thyroid cancer, US guidance allows a correct and safe sampling also of small or deeply located thyroid lesions. Obtained in this way, cytological or microhistological specimens may reliably define the nature of most thyroid nodules, and the information from histochemical or molecular markers shows promise in the classification of the remaining indeterminate cases. While a prompt surgical treatment can be offered in the minority of suspicious or definitely malignant cases, most individuals warrant only a follow-up. However, at initial evaluation, or over the years, a fraction of these benign lesions may grow and/or become symptomatic. Such cases may benefit from US-guided minimally invasive procedures as an alternative to surgery. Image-guided percutaneous treatments most often achieve relief of neck complaints, are inexpensive, and can be performed on an outpatient basis. The risk of major complications, after adequate training, is very low. Importantly, thyroid function is preserved. Currently, percutaneous ethanol injection for cystic lesions and thermal ablation, with laser or radiofrequency, for solid nodules are increasingly used and disseminated beyond the initial core facilities. In centres with expertise and high patient volume, their use should be considered as first-line treatment alternatives to surgery for selected patients with benign enlarging or symptomatic thyroid lesions.

Ultrasound-guided interstitial laser ablation for thyroid nodules is effective only at high total amounts of energy: results from a three-year pilot study

OBJECTIVE

According to cross-sectional surveys, the prevalence of nontoxic nodular goiter appears to be higher in the adult population. Surgical intervention is indicated for the following: (a) progressive goiter growth, (b) compression of organs such as the trachea and esophagus, and (c) significant aesthetic disfigurement. Ultrasound-guided laser photocoagulation for the treatment of benign thyroid nodules is a viable alternative to traditional surgery. However, studies that have appeared in literature since the introduction of ultrasound-guided laser photocoagulation for the treatment of benign thyroid nodules report contradictory data concerning the energy required for nodule ablation. The aim of the present trial was to evaluate retrospectively the efficacy of percutaneous laser thermal ablation in 2 groups of patients, one treated with low, and the other with high, total amount of energy.

DESIGN

Forty euthyroid patients were treated with 1 session of percutaneous laser photocoagulation treatment at low (median = 71 J/mL; 20 patients) and high (median = 578 J/mL; 20 patients) energy. The volume of the nodules was measured by the same investigator, blinded for treatment, using the ellipsoid formula before treatment, at 2, 4, 8, and 30 weeks, and every 6 months for 3 years thereafter.

RESULTS

Thyroid nodule ablation is effective over time only if a sufficient amount of energy (>400-500 J/mL for the nodular tissue to be treated) is given, although it incurs proportionate side effects.

CONCLUSIONS

Percutaneous laser thermal ablation is a viable alternative to traditional surgery for the treatment of benign nodular thyroid disease only if a sufficient amount of energy is delivered.

Tracheal laceration after laser ablation of nodular goitre

A tracheal perforation was discovered after Nd-YAG laser thermal ablation (LTA) of a thyroid nodule. The LTA is a relatively new method of treatment of thyroid nodules, which consists of delivering laser energy into the thyroid by means of two optical fibres. The patient presented with a multinodular goitre and initially refused surgery, then underwent an LTA of a thyroid nodule. Fifty days after the procedure she started to have symptoms related to a tracheal stenosis and, after tracheoscopy, a tracheal perforation was diagnosed and she underwent a total thyroidectomy plus tracheal repair. The results of the histological examination revealed a goitre with a focal area of papillary carcinoma. This particular complication is likely the first of its kind to be described after the LTA of a thyroid nodule.

Effectiveness of various thermal ablation techniques for the treatment of nodular thyroid disease--comparison of laser-induced thermotherapy and bipolar radiofrequency ablation

Alternative minimally invasive treatment options such as radiofrequency ablation (RFA) or laser-induced thermotherapy (LITT) are at present under investigation for achieving a nonsurgical targeted cytoreduction in benign and malignant thyroid lesions. So far, studies have not been able to show a secure advantage for neither LITT nor RFA. The aim of this study was to compare the two ablation procedures in terms of their effectiveness. Thermal lesions were induced in porcine thyroid glands either by LITT or bipolar RFA ex vivo (n = 110 each) and in vivo (n = 10 each) using power settings between 10 and 20 W. Temperature spread during application was documented in 5- and 10-mm distance of the applicator. Postinterventional lesion diameters were measured and lesion size was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed in vivo. Lesion volumes induced by LITT ranged between 0.74 ± 0.18 cm(3) (10 W) and 3.80 ± 0.41 cm(3) (20 W) with a maximum of 5.13 ± 0.16 cm(3) at 18 W. The inducible lesion volumes by RFA were between 2.43 ± 0.68 cm(3) (10 W) and 0.91 ± 0.71 cm(3) (20 W) with a maximum of 2.80 ± 0.85 cm(3) at 14 W. The maximum temperatures were 112.9 ± 9.2°C (LITT) and 61.6 ± 13.9°C (RFA) at a distance of 5 mm and 73.2 ± 6.7°C (LITT) and 53.5 ± 8.6°C (RFA) at a distance of 10 mm. The histochemical analysis demonstrates a complete loss of NADPH dehydrogenase activity in thermal lesions as a sign of irreversible cell damage both for LITT and RFA. This study is the first to compare the effectiveness of laser-induced thermotherapy and radiofrequency ablation of thyroid tissue. LITT as well as RFA are suitable for singular thyroid nodules and induces reproducible clinically relevant lesions in an appropriate application time. The maximum inducible lesion volumes by LITT are significantly larger than by RFA with the devices used herein.

Percutaneous laser ablation of cold benign thyroid nodules: a 3-year follow-up study in 122 patients

BACKGROUND

Percutaneous laser ablation (PLA) is a proposed therapeutic procedure for the management of benign thyroid nodules. However, long-term results are unknown. The aim of this study was to evaluate retrospectively the safety and effects of PLA treatment in patients with benign nonfunctioning thyroid nodules in a 3-year follow-up.

METHODS

One hundred twenty-two patients (95 women and 27 men; age 52.2 ± 12.3 years) with benign cold thyroid solitary nodules or a dominant nodule within a normo-functioning multinodular goiter (volume range: 2.6-86.4 mL) underwent thermal Nd:YAG laser ablation of thyroid nodular tissue by 1-4 optical fibers positioned into the tissue by 21-gauge needles under ultrasound real-time assistance. The setting was an interventional suite and outpatient endocrine clinics in a community hospital in Italy. Nodule volume, ablation volume, side effects, serum thyroid-stimulating hormone (TSH), free triiodothyronine, free thyroxine (fT4), thyroglobulin (Tg), anti-Tg, anti-thyroperoxidase antibodies, symptoms, and cosmetic signs were recorded.

RESULTS

Data are mean ± standard deviation. Energy delivered was 8522  ± 5365 J with an output power of 3.1 ± 0.5 W. Three years after PLA, nodule volume decreased from 23.1 ± 21.3 to 12.5 ± 18.8 mL (-47.8%  ± 33.1% of initial volume, p ≤ 0.001). At day 1, TSH and fT4 values significantly changed (time 0 vs. day 1: TSH = 1.16  ± 1.06 vs. 0.62 ± 0.81 μU/mL, p ≤ 0.001; fT4 = 11.68 ± 1.88 vs. 13.20 ± 3.32 pg/mL, p ≤ 0.01) and normalized within 1 month. No change in free triiodothyronine, thyroperoxidase antibodies, and Tg antibodies values was observed. Symptoms improved in 89 patients (73.0%), were unchanged in 28 (22.9%), and worsened in 5 (4.1%). Cosmetic signs improved in 87 patients (71.3%), were unchanged in 29 (23.8%), and worsened in 6 (4.9%). In 11 patients (9%), nodules regrew above baseline. Two patients (1.6%) experienced delayed (12-24 hours) laryngeal dysfunction with vocal cord motility recovery after 6-10 weeks. Two patients (1.6%) became hypothyroid and two patients (1.6%) hyperthyroid after PLA.

CONCLUSIONS

After 3 years, the PLA technique achieved shrinkage of about 50% of the initial volume in a wide size range of benign cold thyroid nodules, with an improvement in local symptoms and signs. Side effects and failures were few although not negligible. PLA may be a new option for the management of benign cold thyroid nodules. Long-term controlled studies are required to establish the eligibility of patients for routine PLA.

Ex vivo and in vivo evaluation of laser-induced thermotherapy for nodular thyroid disease

BACKGROUND AND OBJECTIVE

The prevalence of thyroid nodules ranges between 2% and 60% depending on the population studied. However, minimally invasive procedures like laser-induced thermotherapy (LITT) are increasingly used to treat tumors of parenchymatous organs and seem to be suitable for singular thyroid nodules as well. Their successful clinical application depends on the induction of sufficiently large lesions and a knowledge of the energy parameters required for complete thermal ablation. The aim of this study was to establish a dose-response relationship for LITT of thyroid nodules.

MATERIALS AND METHODS

Thermal lesions were induced in healthy porcine thyroid glands ex vivo (n = 110) and in vivo (n = 10) using an Nd:YAG laser (1,064 nm). Laser energy was applied for 300 seconds in a power range of 10-20 W. During the ablation, continuous temperature measurement at a distance of 5 and 10 mm from the applicator was performed. The lesions were longitudinally and transversally measured, and the volume was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed.

RESULTS

The maximum inducible lesion volumes were between 0.74 +/- 0.18 cm(3) at a laser power of 10 W and 3.80 +/- 0.41 cm(3) at 20 W. The maximum temperatures after ablation were between 72.9 +/- 2.9 degrees C (10 W) and 112.9 +/- 9.2 degrees C (20 W) at a distance of 5 mm and between 49.5 +/- 2.2 degrees C (10 W) and 73.2 +/- 6.7 degrees C (20 W) at a distance of 10 mm from the applicator. The histochemical analysis demonstrates a complete loss of NADPH dehydrogenase activity in thermal lesions as a sign of irreversible cell damage.

CONCLUSIONS

This study is the first to demonstrate a dose-response relationship for LITT of thyroid tissue. LITT is suitable for singular thyroid nodules and induces reproducible clinically relevant lesions with irreversible cell damage in an appropriate application time.

Bipolar radiofrequency ablation for nodular thyroid disease--ex vivo and in vivo evaluation of a dose-response relationship

BACKGROUND

The prevalence of thyroid nodules ranges between 2% and 60% depending on the population studied. However, minimally invasive procedures like radiofrequency ablation (rfA) are increasingly used to treat tumors of parenchymatous organs, and seem to be suitable for singular thyroid nodules as well. Their successful clinical application depends on the induction of sufficiently large lesions and a knowledge of the energy parameters required for complete thermal ablation. The aim of this study was to establish a dose-response relationship for rfA of thyroid nodules.

MATERIAL AND METHODS

Thermal lesions were induced in healthy porcine thyroid glands ex vivo (n=110) and in vivo (n=10) using a bipolar radiofrequency system; rf was applied in a power range of 10-20 watts. During the ablation, continuous temperature measurement at a distance of 5 and 10 mm from the applicator was performed. The transversal and axial lesion diameters were measured, and the volume was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed.

RESULTS

The inducible lesion volumes were between 0.91±0.71 cm(3) at 20W and 2.80±0.85 cm(3) at 14W. The maximum temperatures after rf ablation were between 44.0±9.7°C and 61.6±13.9°C at a distance of 5 mm and between 30.0±8.6°C and 53.5±8.6°C at a distance of 10 mm from the applicator. The histochemical analysis demonstrates a complete loss of nicotinamide adenine dinucleotide phosphate-oxidase (NADPH) dehydrogenase activity in thermal lesions as a sign of irreversible cell damage.

CONCLUSION

This study is the first to demonstrate a dose-response relationship for rfA of thyroid tissue. rfA is suitable for singular thyroid nodules and induces reproducible, clinically relevant lesions with irreversible cell damage in an appropriate application time.

Percutaneous laser ablation of benign and malignant thyroid nodules

PURPOSE OF REVIEW

Percutaneous image-guided procedures, largely based on thermal ablation, are at present under investigation for achieving a nonsurgical targeted cytoreduction in benign and malignant thyroid lesions.

RECENT FINDINGS

In several uncontrolled clinical trials and in two randomized clinical trials, laser ablation has demonstrated a good efficacy and safety for the shrinkage of benign cold thyroid nodules. In hyperfunctioning nodules, laser ablation induced a nearly 50% volume reduction with a variable frequency of normalization of thyroid-stimulating hormone levels. Laser ablation has been tested for the palliative treatment of poorly differentiated thyroid carcinomas, local recurrences or distant metastases.

SUMMARY

Laser ablation therapy is indicated for the shrinkage of benign cold nodules in patients with local pressure symptoms who are at high surgical risk. The treatment should be performed only by well trained operators and after a careful cytological evaluation. Laser ablation does not seem to be consistently effective in the long-term control of hyperfunctioning thyroid nodules and is not an alternative treatment to 131I therapy. Laser ablation may be considered for the cytoreduction of tumor tissue prior to external radiation therapy or chemotherapy of local or distant recurrences of thyroid malignancy that are not amenable to surgical or radioiodine treatment.