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

Efficacy of HIFU for the treatment of benign thyroid nodules: a systematic review and meta-analysis

OBJECTIVE

Thyroid nodules are common and sometimes associated with cosmetic issues. Surgical treatment has several disadvantages, including visible scarring. High-intensity focused ultrasound (HIFU) is a recent noninvasive treatment for thyroid nodules. The present study aims to evaluate the effectiveness and safety of HIFU for the treatment of benign thyroid nodules.

METHODS

We searched PubMed, Embase, and Cochrane Library for studies evaluating the outcomes of HIFU for patients with benign thyroid nodules. We conducted a meta-analysis by using a random effects model and evaluated the volume reduction ratio, treatment success rate, and incidence of treatment-related complications.

RESULTS

Thirty-two studies were included in the systematic review. Only 14 studies were used in the meta-analysis because the other 18 involved data collected during overlapping periods. The average volume reduction ratios at 3, 6, and 12 months after treatment were 39.02% (95% CI: 27.57 to 50.47%, I2: 97.9%), 48.55% (95% CI: 35.53 to 61.57%, I2: 98.2%), and 55.02% (95% CI: 41.55 to 68.48%, I2: 99%), respectively. Regarding complications, the incidences of vocal cord paresis and Horner's syndrome after HIFU were 2.1% (95% CI: 0.2 to 4.1%, I2: 14.6%) and 0.7% (95% CI: 0 to 1.9%, I2: 0%), respectively.

CONCLUSIONS

HIFU is an effective and safe treatment option for patients with benign thyroid nodules. However, the effects of HIFU on nodules of large sizes and with different properties require further investigation. Additional studies, particularly randomized controlled trials involving long-term follow-up, are warranted.

CLINICAL RELEVANCE STATEMENT

Surgical treatment for thyroid nodules often results in permanent visible scars and is associated with a risk of bleeding, nerve injury, and hypothyroidism. High-intensity focused ultrasound may be an alternative for patients with benign thyroid nodules.

KEY POINTS

• The success rate of HIFU treatment for thyroid nodules is 75.8% at 6 months. Average volume reduction ratios are 48.55% and 55.02% at 6 and 12 months. • The incidence of complications such as vocal fold paresis, Horner's syndrome, recurrent laryngeal nerve palsy, hypothyroidism, and skin redness is low. • HIFU is both effective and safe as a treatment for benign thyroid nodules.

Minimally Invasive Treatments of Benign Thyroid Nodules: A Network Meta-Analysis of Short-Term Outcomes

Background: Image-guided thermal ablation interventions are novel thermal-based modalities used for the treatment of benign thyroid nodules. Methods: We conducted a systematic review and a Bayesian network meta-analysis, examining studies using thermal ablation interventions in the treatment of benign nodular thyroid disease (PROSPERO CRD42022367680). The primary endpoints included volume reduction rate (VRR), and symptomatic score and cosmetic score improvement. Secondary endpoints included vocal disturbances, laryngeal nerve palsy, hypothyroidism, and nodular regrowth (defined by increased nodular volume of >50% for thermal ablation or new nodules arising in remaining thyroid tissue conventional surgery [CS]). Results: We included 16 studies (3 randomized controlled trials [RCTs] and 13 comparative case series), describing radiofrequency ablation (RFA), laser ablation (LA), microwave ablation (MWA), high-intensity focus ultrasound (HIFU), and CS, respectively. The review included data from 4112 patients followed for a mean of 11.9 months. Meta-analyses showed no significant differences among RFA, LA, MWA, HIFU, and CS regarding any of the primary endpoints of VRR, symptomatic score, and cosmetic score. In examining the surface under the cumulative ranking area (SUCRA) ranking, CS (SUCRA, 98.49), LA (SUCRA, 51.58), and MWA (SUCRA, 57.0) were identified as the three interventions that were most likely to result in the largest VRR, symptomatic and cosmetic score reduction. RFA, relative risk (RR) 0.19 [95% credibility interval (CI): 0.06 to 0.48], LA RR 0.23 [CI: 0.06 to 0.79], and MWA RR 0.25 [CI: 0.09 to 0.60] were associated with the greatest reduction in risk for postintervention vocal complications compared with CS, with RFA (SUCRA, 61.62) being ranked as the highest in safety. RFA RR 0.05 [CI: 0.00 to 0.40] and MWA RR 0.16 [CI: 0.02 to 0.73] were associated with a reduced risk of transient laryngeal nerve injury compared with CS. RFA RR 0.00 [CI: 0.00 to 0.00] and MWA RR 0.00 [CI: 0.00 to 0.03] were associated with a reduced risk of hypothyroidism occurrence compared with CS, with RFA (SUCRA, 99.86) yielding the highest safety ranking. RFA was associated with a reduced risk for nodular regrowth RR 0.09 [CI: 0.00 to 0.85], compared with CS. Conclusion: We have comprehensively reviewed the published literature on the efficacy and safety of thermal ablation modalities for benign thyroid nodules. Important research gaps remain regarding a paucity of both long-term data and high-quality RCTs.

Minimally Invasive Techniques for the Management of Thyroid Nodules

Image-guided interventional techniques have emerged as promising treatments for thyroid disease. Percutaneous ethanol ablation, radiofrequency ablation, laser ablation, high intensity focused ultrasound, and microwave ablation have shown efficacy in treating benign thyroid disease. There is increasing evidence that these techniques may effectively treat papillary thyroid microcarcinomas, recurrent and metastatic disease, follicular neoplasms, and parathyroid lesions. They are performed in an outpatient setting, well-tolerated, with negligible risk for thyroid hormone supplementation, making them a popular alternative to surgical resection. In this comprehensive review, we discuss the devices, techniques, advantages, and disadvantages of each intervention, and summarize the published outcomes.

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.

Phenotypic alterations in liver cancer cells induced by mechanochemical disruption

Hepatocellular carcinoma (HCC) is a highly fatal disease recognized as a growing global health crisis worldwide. Currently, no curative treatment is available for early-to-intermediate stage HCC, characterized by large and/or multifocal tumors. If left untreated, HCC rapidly progresses to a lethal stage due to favorable conditions for metastatic spread. Mechanochemical disruption of cellular structures can potentially induce phenotypic alterations in surviving tumor cells that prevent HCC progression. In this paper, HCC response to mechanical vibration via high-intensity focused ultrasound and a chemical disruptive agent (ethanol) was examined in vitro and in vivo. Our analysis revealed that mechanochemical disruption caused a significant overproduction of reactive oxygen species (ROS) in multiple HCC cell lines (HepG2, PLC/PRF/5, and Hep3B). This led to a decrease in cell viability and long-term proliferation due to increased expression and activity of death receptors TNFR1 and Fas. The cells that survived mechanochemical disruption had a reduced expression of cancer stem cell markers (CD133, CD90, CD49f) and a diminished colony-forming ability. Mechanochemical disruption also impeded HCC migration and their adhesion to vascular endothelium, two critical processes in hematogenous metastasis. The HCC transformation to a non-tumorigenic phenotype post mechanochemical disruption was confirmed by a lack of tumor spheroid formation in vitro and complete tumor regression in vivo. These results show that mechanochemical disruption inhibits uncontrolled proliferation and reduces tumorigenicity and aggressiveness of HCC cells through ROS overproduction and associated activation of TNF- and Fas-mediated cell death signaling. Our study identifies a novel curative therapeutic approach that can prevent the development of aggressive HCC phenotypes.

Comparison of high intensity focused ultrasound and radioiodine for treating toxic thyroid nodules

PURPOSE

We compared the effectiveness of high intensity focused ultrasound (HIFU) and radioiodine (RAI) to treat patients carrying toxic thyroid nodule (TTN). Normalization of serum thyrotropin (TSH) 1 year after treatment was the primary end-point; concurrent changes in nodules' volume and scintigraphic pattern were also evaluated as secondary end-points.

MATERIALS AND METHODS

Among patients ≥18 years old with TTN observed at our centre between January 1st, 2016 and December 31th, 2016 we prospectively enrolled 17 and 15 age and sex-matched patients treated with RAI and HIFU, respectively. Biochemical thyroid tests and nodules' volume were assessed before and 3, 6 and 12 months after treatments. A thyroid scintigraphy was performed before and 1 year after treatment, respectively.

RESULTS

The final series included 17 patients treated with RAI and 15 patients treated with HIFU, respectively. Neither demographic nor clinical differences were found at baseline. One year after treatment 14 of 17 RAI-treated and 4 of 15 HIFU-treated patients fulfilled criteria for response to treatment (P = .0008). Indeed, the median TSH value was 1.5 IU/mL and 0.2 IU/mL in HIFU and RAI groups, respectively (P < .0001). Finally, despite a similar decrease in nodules' volume in both groups, a scintigraphic response was achieved in 16 of 17 (94%) RAI-treated compared to 8 of 15 (53%) HIFU-treated patients (P = .024), respectively.

CONCLUSIONS

In our series, RAI clearly outperforms HIFU in treating patients carrying TTN and remains the first-line noninvasive treatment in such cases.

High-intensity focused ultrasound (HIFU) therapy for benign thyroid nodules without anesthesia or sedation

BACKGROUND

Thermal ablation of thyroid nodules has gained momentum due to the possibility to avoid surgery. High-intensity focused ultrasound (HIFU) allows thermal treatment by energy ultrasound beam inside the targeted zone. Aim of our study was to evaluate the effects of HIFU treatment using Beamotion mode without anesthesia.

METHODS

Since 2016, patients with normal thyroid function, benign thyroid nodules with diameter no larger than 4 cm, and presenting local discomfort and/or compressive symptoms were treated by HIFU. We performed Beamotion HIFU and did not use anesthesia. Nodule size and thyroid function were evaluated before HIFU and 6 and 12 months later. Complications to therapy and tolerability of patients were also recorded. According to local ethical committee, for this retrospective study formal consent was not required.

RESULTS

The final series included 26 nodules from 26 patients with estimated volume of 2.81 ± 2.04 mL, treated by a power of 33.3 ± 10.3 W/site and energy of 2.1 ± 1.1 kJ. Nodules volume was significantly (p < 0.0001) reduced at 6 months of follow-up (1.83 ± 1.63 mL), and further at 1 year (1.57 ± 1.47 mL). Mean percentage of reduction over time of nodules was 48%. A 73% of patients described good comfort during treatment, 100% experienced good comfort just after therapy, and tolerability was high. No complications were recorded. At one 1 year of follow-up, 85% of subjects reported a reduction of local symptoms.

CONCLUSIONS

HIFU therapy is effective in reducing size of thyroid nodules with major diameter below 4 cm and can be performed without anesthesia.

Image-guided chemical and thermal ablations for thyroid disease: Review of efficacy and complications

Image-guided ablation of thyroid disease is increasingly being commonly reported. Techniques including ethanol injection and thermal ablation using radio-frequency, laser, and microwave devices have been described. Minimally invasive approaches to the management of benign cystic, solid, and functional thyroid nodules as well as both primary and recurrent thyroid malignancy have been reported. The purpose of this article is to review the current evidence relating to image-guided ablation of thyroid disease with a focus on clinical outcomes and complication rates for patients treated with this minimally invasive approach.

Treatment of benign thyroid nodules by high intensity focused ultrasound (HIFU) at different acoustic powers: a study on in-silico phantom

BACKGROUND

The non-surgical therapies of benign thyroid nodules are gaining momentum due to the possibility to reduce the nodule's volume and avoid surgery. As the last technique introduced, high intensity focused ultrasound allows the thermal tissue treatment by directing energy inside the targeted nodule with no invasive instruments. In the present study we applied the Food and Drug Administration high intensity focused ultrasound simulator to in-silico phantom to evaluate the effects obtained by different acoustic powers.

METHODS

The simulated layers were water and thyroid tissue. The source was a spherically curved circular transducer with radius r   = 2.3 cm generating a continuous wave beam at a frequency of 3 MHz. The focal distance was 6.5 cm. The sequence included a pulse (8 s) with acoustic power at different value from 5 to 50 W, and a cooling-off interval (32 s).

RESULTS

The use of acoustic power of 5 W allowed to achieve the threshold of temperature for coagulative necrosis (55 °C) at 1 s. The simulation with 50 W showed that temperature was significantly higher (above 300 °C) at 1 s and is maintained at high levels for a long interval.

CONCLUSION

Since 2016, we treated patients according to the present experience, and a significant reduction of nodule's volume was observed with good patent's comfort and no complications (unpublished data). Also, no anesthesia was practiced. We feel that the present data could contribute to develop a high intensity focused ultrasound therapy of benign thyroid nodules free from potential complications.

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.

Bortezomib sensitizes thyroid cancer to BRAF inhibitor in vitro and in vivo

Although overall survival rate for patients with thyroid cancer (TC) is high, there is an alarming 10-year recurrence rate of up to 30% conferring a ~50% survival among these high-risk patients. The BRAF^V600E mutation is estimated to be present in over 50% of papillary thyroid cancer (PTC) cases besides being associated with carcinogenesis and poor prognosis. We assessed the status of NF-κB, Ki-67, cyclin D1 and BRAF^V600E in TC tissues and TC cell lines using immunohistochemistry and Western blot analysis. Concurrently, we evaluated the outcomes of combined targeting of the proteasome pathway in addition to selective BRAF inhibitors in cases of PTC. In this study, BRAF^V600E-bearing TC cells were treated with BRAF^V600E inhibitor, Vemurafenib alone or in combination with the proteasome inhibitor, Bortezomib. The combination of both drugs showed synergistic effects as evidenced by cell growth inhibition (P < 0.05), increased G2-phase cell cycle arrest and induced apoptosis (P < 0.05). In our TC xenograft model, the combination of Vemurafenib and Bortezomib significantly reduced tumor size (P < 0.05) and expression of the markers of cell growth and proliferation, Ki-67 and cyclin D1 (P < 0.001), when compared to monotherapy. Further analysis demonstrated that treatment with Bortezomib sensitized TC cells to Vemurafenib via mitochondrial dysregulation and apoptosis of TC cells, as evidenced by the increase in the expression of p53, Noxa protein, the loss of mitochondrial membrane potential, cytochrome c release and Poly (ADP-ribose) polymerase cleavage. Our results demonstrate a strong clinical potential for the combination of the Bortezomib and the BRAF inhibitor Vemurafenib as an efficient therapeutic approach for the treatment of TC.

High intensity focused ultrasound (HIFU) ablation of benign thyroid nodules - a systematic review

Background

With an increasing number of imaging studies being done nowadays, the number of incidentally discovered thyroid nodules is expected to rise. Although many of these nodules are small and benign in nature, some do grow and may cause pressure and/or thyrotoxic symptoms. Surgical resection has traditionally been recommended for symptomatic nodules but is associated with risk of hypothyroidism, bleeding, infection, and nerve damage. High intensity focused ultrasound (HIFU) is one of the non-surgical thermal ablation techniques that may serve as an alternative in the treatment of benign thyroid nodules. The present review is to systematically evaluate the efficacy and safety of HIFU ablation.

Methods

We comprehensively searched all studies that evaluated the use of HIFU ablation as a treatment of benign thyroid nodules from Medline (PubMed) and Cochrane Library electronic databases using specific keywords. All titles identified by the search strategy were independently screened by two authors. Case reports, animal studies, editorials, expert opinions, reviews without original data and studies on pediatric population were excluded. Multiple reports of the same dataset were assessed and the most representative and updated report of a study was included.

Results

Five original studies were found. All treated thyroid nodules were confirmed to be benign cytologically and either appeared solid or predominantly (>70%) solid on ultrasonography. Only one type of commercially available US-guided device with an extracorporeal probe (3 MHz) was used in all the reported treatments. No major complications including recurrent laryngeal nerve injury, skin burn or haematoma were reported in all of the studies. The overall nodule volume reduction after single session of HIFU ablation ranged between 45 and 68%, depending on nodule size and length of follow-up.

Conclusions

Despite the few number of studies, our review appeared to suggest that HIFU is a safe and efficacious method of treating symptomatic benign thyroid nodules. However, larger-scale, prospective trials with longer follow-up period are indeed required to confirm this. In terms of the ablation itself, relative to other ablation techniques, there are still much room for improvements in shortening treatment duration and expanding the range of treatable nodules.

Image-guided thermal ablation of benign thyroid nodules

Benign thyroid nodules are a common disease in the general population. Most often, they are completely asymptomatic and discovered occasionally during routine ultrasound examinations, and do not require any treatment. When thyroid nodules become symptomatic, surgical excision is still considered standard treatment. In the last few years, several experiences in the treatment of benign thyroid nodules through image-guided percutaneous thermal ablation have been reported with encouraging results, so that currently, these treatments are often proposed as first-choice options for patients with symptomatic benign thyroid nodules. In this paper, we discuss the present literature on the topic, focusing on different techniques available for image-guided percutaneous ablation, particularly radiofrequency (RFA), laser (LA), microwave (MWA), and high-intensity-focus ultrasound (HIFU). Little evidence about the efficacy of MWA and HIFU is now available. According to the literature, good results have been obtained with RFA and LA. Regarding RFA, volume reduction after ablative treatment has been found to range from 47 to 84 % at 3-6 months, and from 62 to 93 % at 1 year; LA also seems to be effective in achieving shrinkage of thyroid nodules, with volume reduction from 37 to 81 % at 3-6 months, and from 13 to 82 % at 1-year follow-up. Moreover, applications of advanced image-guidance modality, such as contrast-enhanced ultrasound and virtual navigation with fusion imaging, are discussed.

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.

Volume reduction of benign thyroid nodules 3 months after a single treatment with high-intensity focused ultrasound (HIFU)

Background

High-intensity focused ultrasound (HIFU) is a promising, non-invasive technique in treating benign thyroid nodules (TNs). The aim of this study was to evaluate the efficacy of HIFU to induce clinically meaningful shrinkage in benign predominantly solid TNs and to identify variables that influence or predict the magnitude of TN volume reduction.

Methods

For each of ten subjects, HIFU treatment was conducted on a single nodule. Nodular volume was measured sonographically at baseline and at 3 months post-procedure. Nodular function and early treatment assessment was done scintigraphically.

Results

Median nodular volume reduction was 0.7 ml absolute and 48.8% relative to pre-interventional size (p < 0.05). Absolute shrinkage was negatively correlated with the average treatment depth (τ = −0.61, p < 0.05). Absolute nodular volume was positively correlated with the scintigraphic nodular uptake reduction (τ = 0.66, p < 0.05).

Conclusions

HIFU treatment of benign predominantly solid TNs appears to be safe and effective for inducing nodular shrinkage. Despite potential for improvement, a single treatment session with HIFU is already a viable alternative to more standard methods. The feasibility of multiple HIFU treatments requires further investigation. Due to the small sample size, the findings of this analysis need conformation by larger studies.

Local thyroid tissue ablation by high-intensity focused ultrasound: effects on thyroid function and first human feasibility study with hot and cold thyroid nodules

OBJECTIVE

The aim of this study was to assess whether high-intensity focused ultrasound (HIFU), a new and promising method for the treatment of benign hot and cold thyroid nodules using thermal ablation, has an impact on thyroid function, and to evaluate its feasibility in outpatient settings. Additionally, a possible difference in the treatment of solid and complex thyroid nodules was evaluated.

METHOD

Ten patients with one thyroid nodule each (six cold and four hot nodules) underwent HIFU in January 2014. Four nodules were solid and six nodules were complex. Serum levels of triiodothyronine (T3), thyroxine (T4), thyrotropin (TSH), thyroglobulin (hTg) and additionally antibodies against hTg (TAK), TSH receptors (TRAK) and thyroid peroxidase (TPO) were measured at enrolment and 24 h after the HIFU treatment. The pre- and post-thyroglobulin reduction was measured to evaluate the scale of ablation. In addition, patients' pain was recorded on a numeric rating scale from 0 to 10.

RESULTS

The HIFU treatment did not affect thyroid function, since hormone levels stayed stable (p < 0.05). No serious immune reaction was induced. Thyroglobulin serum levels increased significantly (p < 0.05) and were correlated to the total energy emitted by HIFU (p < 0.1). The results of complex thyroid nodules did not differ from solid thyroid nodules. Similarly, the results of hot thyroid nodules did not differ from cold thyroid nodules. All patients tolerated the whole treatment and no severe complications were observed.

CONCLUSION

HIFU is a safe and effective method to treat benign, solid, complex, hot and cold thyroid nodules preserving thyroid function. Further developments of the system are needed to gain suitability for daily use.

Early assessment of high-intensity focused ultrasound treatment of benign thyroid nodules by scintigraphic means

Background

High-intensity focused ultrasound (HIFU) allows to inflict intracorporal thermal lesions without penetrating the skin or damaging the surrounding tissue. This analysis intends to assess the magnitude of HIFU-induced ablations within benign thyroid nodules using scintigraphic imaging with ^99mTc.

Methods

Ten cold, hot, or indifferent nodules were treated using multiple pulses of HIFU to induce temperatures of around 85°C within the ablation zone. Pre- and posttreatment, uptake values of ^99mTc-pertechnetate or ^99mTc-MIBI were recorded. The pre-post reduction of nodular uptake was evaluated to assess ablation magnitude.

Results

Relative nodular uptake in relation to total thyroidal uptake decreased after one session of HIFU in all cases. Median ^99mTc-MIBI uptake reduction was 35.5% (ranging from 11% to 57%; p < 0.1), while ^99mTc-pertechnetate scintigraphy showed a median uptake reduction of 27% (range 10% to 44%; p < 0.1). No major complications were observed.

Conclusions

HIFU appears to be safe and is an easy to perform means of thermal ablation. This study shows that HIFU treatment in thyroidal nodules can be evaluated by scintigraphic means shortly after the intervention. Due to small sample size, the exact magnitude of HIFU ablation efficiency in thyroidal nodules remains a value to be assessed in a larger study.

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.

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.

Image-guided percutaneous ablation therapies for local recurrences of thyroid tumors

The incidence of thyroid carcinoma has increased steadily over the last few decades. Most differentiated thyroid carcinomas (DTC) are cured thanks to the initial treatment with surgery and radioiodine therapy. Nevertheless, neck lymph node metastases are found in a few of these patients during their long-term clinical and ultrasound follow-up. In some of these cases radioiodine treatment may not be effective in eradicating nodal metastases due to scant 131-I uptake. Additionally, a few of these patients undergo repeated neck explorations and/or resections. Based on these considerations and on the frequently indolent course of DTC neck metastases, a non-surgical therapeutic approach should be considered to control small local foci of DTC. There is increasing interest in mini-invasive image-guided procedures that can be performed under local anesthesia which do not affect the performance status of the patient. Image-guided minimally invasive ablative therapies delivered by using needle-like applicators include both thermal and non-thermal source techniques. Over the past 25 years, these therapies have gained widespread attention and, in many cases, broad clinical acceptance as methods for treating focal malignancies. In an attempt to overcome the limitations of treating certain unresectable tumor types not amenable to a further surgical treatment, a few investigators have reported successfully combining percutaneous therapies with other oncologic treatment strategies (combined treatments). In this review, we reported mini-invasive techniques more commonly employed in selected cases to ameliorate local compressive symptoms, control hormonal production, and reduce the volume of neoplastic tissue prior to traditional palliative treatment.

High-intensity focused ultrasound as an alternative to the surgical approach in primary hyperparathyroidism: a preliminary experience

BACKGROUND

Surgery is the therapy of choice in primary hyperparathyroidism (PHPT), although other less invasive techniques have been used in the attempt to cure the disease. Recently, high-intensity focused ultrasound (HIFU), a totally non-invasive technique, has become available to cure solid tumors.

AIM

The aim of this pilot study has been to assess the safety and efficacy of HIFU in symptomatic patients with PHPT.

MATERIAL AND METHODS

Four out of 31 patients with surgical indications within a cohort of 47-screened patients with PHPT were considered eligible for the study. All patients accepted to participate and were submitted to HIFU treatment in a single session. One patient was submitted to surgery after HIFU treatment. Patients were followed-up for 12 months after the procedure.

RESULTS

A persistent or a partial remission of the disease, respectively, were obtained in 2 patients (50%), including the one who underwent surgery after HIFU treatment. Safety was assessed performing laryngoscopy in all patients after HIFU procedure. A transient vocal cord paralysis was observed in all patients treated by HIFU only. No permanent side effects were observed in the long term.

CONCLUSIONS

HIFU might be a promising technique in treating PHPT, provided that further development of the software decreases the rate of side effects and improves the short- and long-term efficacy.

Mini-invasive video-assisted surgery of the thyroid and parathyroid glands: a 2011 update

Thyroid surgery during the last century was characterized by a development of Kocher's concepts: through a relentless work of surgeons from all over the world thyroidectomy reached a standard of quality in terms of overall results which was unimaginable in the first half of the XX century. The flattering data collected in the literature until the 90's were all concordant in assuming that there would be little space for a real improvement in the quality standard of thyroid surgery. The introduction of laparoscopic surgery, though, changed very quickly the attitude of surgeons towards their operative behavior and countless new mini-invasive techniques were soon proposed for almost any field of surgery. In 1994, Gagner published the first series of laparoscopic adrenalectomies. Soon after, parathyroid adenomas seemed to offer an ideal field of application of these new surgical concepts. The first report of an endoscopic parathyroidectomy was in 1996. One year later other videoscopic procedures were described whose results seemed quite encouraging so as to push surgeons to try the same access and the same technique also for operations on thyroid. During the following decade several endoscopic or video-assisted approaches were proposed for the removal of thyroid gland. This paper aims to evaluate the results of minimally invasive thyroid and parathyroid surgery through an extensive review of the literature, in particular as far as minimally invasive video-assisted thyroidectomy is concerned.

Good practice guide for cervical ultrasound scan and echo-guided techniques in treating differentiated thyroid cancer of vesicular origin

Good practice guide for cervical ultrasound scan and echo-guided techniques in treating differentiated thyroid cancer of vesicular origin. American, European and French Recommendations for the treatment of differentiated vesicular thyroid cancer were recently published. Cervical ultrasound scanning is now considered a key examination in the follow-up of these cancers. This examination is noninvasive, easy to perform and to obtain, is not costly, but remains operator-dependent. To date, there are no recommendations published that assemble all the technical aspects, results, indications and the limits of this examination in the initial medical report and the follow-up of these cancers. In order to standardise the procedure and validate the quality of the examination, a workgroup made up of a panel of experts particularly involved in carrying out ultrasound scans was set up. The aim was to draw up a good practice guide for performing cervical ultrasound scans and echo-guided techniques in treating patients with differentiated thyroid cancer of vesicular origin. The main objectives are to: (a) standardise the procedure and reports, (b) define the criteria for establishing whether lesions identified during a cervical ultrasound scan are malignant or benign, (c) standardise the indications for carrying out cytological tests and an in situ assay of markers, (d) help doctors to select the patients who ought to receive a cervical ultrasound scan and or cytological tests, (e) discuss how frequently the examinations should be carried out depending on the risk of recurrence.