A Novel Strategy for Single-Session Ultrasound-Guided Radiofrequency Ablation of Large Benign Thyroid Nodules: A Pilot Cohort Study

Morphological, clinical, and functional efficacy in the short and medium-term after radiofrequency treatment of predominantly solid, large, and clinically relevant thyroid nodules in patients who are not candidates for surgery: The experience after 100 procedures

INTRODUCTION

Thyroid nodules (TN) are a prevalent pathology that can generate morbidity, in which case the traditional treatment is usually surgery.

OBJECTIVE

To analyse the efficacy of radiofrequency ablation (RFA) treatment as a therapeutic alternative in the combined clinical, morphological, and functional control of predominantly solid, benign and clinically relevant TNs in patients not subsidiary to surgery.

MATERIALS AND METHODS

A descriptive, retrospective, case series study was carried out to assess the efficacy and safety of the use of RFA. According to medical criteria, the selected patients underwent a clinical, ultrasound, and biochemical assessment prior to the procedure and then after the procedure at 1, 3, 6, and 12 months and then every 6-12 months according to medical criteria.

RESULTS

A total of 100 RFA were performed on 83 patients with 85 TNs of ≥2.5 cm with an initial volume (IV) of 21.48 ± 15.89 ml. After a mean of 1.17 RFA sessions per TN, the volume decreased progressively and significantly (p < 0.01 for all times compared to the initial value), with a mean volume reduction rate (VRR) in relation to the IV of 54.43 ± 19.56% at 1-month follow-up; 67.69 ± 17% at 3 months; 70.38 ± 15.46% at 6 months; 70.67 ± 17.27% at 12 months and 70.24 ± 17.7% at the last follow-up. 88% of the patients followed up >6 months achieved the combined objective of a volume reduction rate of more than 50% of the VI, thyroid normal function and absence of clinic; and in all of these, it was maintained until the final follow-up date. Acute complications (mostly mild and all transient) were reported in 9 of the 100 RFA performed.

CONCLUSION

Our findings validate in our setting the efficacy and safety of RFA in predominantly large and solid TNs, and add undescribed information to position the technique more favourably as a therapeutic alternative.

Meta-analysis of the efficacy and safety of thermal ablation for treating large benign thyroid nodules

OBJECTIVE

Many large benign thyroid nodules have symptoms and cosmetic problems. This study consisted of a meta-analysis to accurately assess the effect of thermal ablation on these nodules.

METHODS

The PubMed, Embase, Web of Science, and Scopus databases were systematically searched for retrospective or prospective studies of thermal ablation since June 1, 2021. The weighted mean differences of the measures were analysed before and after treatment.

RESULTS

A total of 10 eligible studies were included. By comparing the initial nodule volume with the nodular volume after thermal ablation, we found that the volume reduction rate was increased significantly after 1 month (SMD = 0.453, 95% CI: 0.323-0.583, p &lt; .001), 3 months (SMD = 0.655, 95% CI: 0.563-0.747, p &lt; .001), 6 months (SMD = 0.691, 95% CI: 0.607-0.774, p &lt; .001), and 12 months (SMD = 0.694, 95% CI: 0.583-0.803), p &lt; .001). The nodular volume was also found to decrease significantly, after 1 month (SMD = 2.381, 95% CI: 1.278-3.485, p &lt; .001), 3 months (SMD = 5.071, 95% CI: 2.386-7.756, p &lt; .001), 6 months (SMD = 5.363, 95% CI: 2.765-7.962, p &lt; .001), and 12 months (SMD = 8.194, 95% CI: 2.113-14.274), p &lt; .001). Symptom score (SMD = 4.419, 95% CI: 2.573-6.265, p &lt; .001)and cosmetic score (SMD = 4.245, 95% CI: 2.566-5.359, p &lt; .001) were reduced after thermal ablation.

CONCLUSIONS

Thermal ablation could become an alternative to manage large benign thyroid nodules.

A novel parallel overlapping mode for complete ablation of large benign thyroid nodules in a single-session radiofrequency ablation

BACKGROUND

Radiofrequency ablation (RFA) has been widely applied in patients with benign thyroid nodules (BTNs), and complete ablation in a single-session treatment brings great benefits to patients. While how the ablation should be planned and performed to achieve complete ablation in a single-session treatment in large BTNs remains unknown.

PURPOSE

To determine a more suitable ablation strategy for sufficient treatment in a single-session treatment.

MATERIALS AND METHODS

This retrospective study included 108 BTNs receiving RFA treatment. These patients were divided into two groups: group A using one insertion point with a fan-shaped overlapping mode and group B using multiple insertion points with a novel parallel overlapping mode. All the treatments used a hydrodissection approach and moving-shot technique. Contrast-enhanced ultrasonography (CEUS) was used to guide the supplementary ablation. Follow-ups were performed at 1, 3, 6 and 12 months. The rates of supplementary ablation, initial ablation ratio (IAR), the rates of complete ablation (CAR), treatment effects and complications between the two groups were compared.

RESULTS

The group B had larger treated nodules (10.2ml vs 6.4ml, P<0.001) than group A, while group B had a lower rate of supplementary ablation (21.6% vs 75.4%, P<0.001), especially in the BTNs with craniocaudal diameters ≥30mm (22.0% vs 100%, P<0.001). With the assistance of supplementary ablation, both groups achieved similar IAR (100% vs 100%, P=0.372) and CAR (94.7% vs 94.1%, P=1.000). Two groups showed similar VRRs at 12-month follow-up (77.9% vs 77.5%, P=0.894) and similar rates of complications (3.5% vs 2.0%, P=1.000).

CONCLUSIONS

Needle placement using the multiple insertion points with a novel parallel overlapping mode would be easier to achieve complete ablation with less supplementary ablation, especially in large nodules.

A long-term retrospective study of ultrasound-guided microwave ablation of thyroid benign solid nodules

PURPOSE

To explore the clinical outcomes and safety of ultrasound-guided microwave ablation (MWA) for treating thyroid benign solid nodules during a three-year follow-up.

METHODS

A total of 53 patients with thyroid benign solid nodules with the largest diameter exceeding 2 cm were treated with US-guided MWA between January 2015 and December 2017. Nodule volume, the cosmetic score, and the symptom scores were evaluated before ablation and 1, 2, and 3 years after the operation. The characteristics of MWA and complications were also evaluated.

RESULTS

The thyroid nodule volume at each time point after ablation was significantly smaller than that before ablation (p < .05). The Symptom and Cosmetics score were significantly improved (p < .05). Hoarseness was the major complication, with an incidence of 1.89%. The original nodules volume was 7.28 ± 11.42 mL; the isolating fluid was 34.36 ± 13.35 mL; the ablation time was 188.77 ± 89.13s.

CONCLUSIONS

MMA is an effective and safe approach for reducing nodule volume and symptoms in patients with benign thyroid solid nodules.

Continuous, Large-Volume Hydrodissection to Protect Delicate Structures around the Thyroid throughout the Radiofrequency Ablation Procedure

INTRODUCTION

Small-volume hydrodissection liquid dissipates rapidly and confers only short-term protection during radiofrequency ablation (RFA) of benign thyroid nodules. The aim of this study was to establish a safe method for continuous, large-volume hydrodissection.

METHODS

A long needle was inserted and positioned outside the thyroid capsule; 5% glucose was injected to maintain a 3- to 5-mm continuous safety buffer. From October 2015 to July 2020, 166 patients underwent hydrodissection with different volumes, and ablation efficacy and complications associated with different liquid volumes (≤40 mL vs. >40 mL) were compared at 1-month postprocedure. Moreover, 20 mL liquid (equivalent to 250 mL in the human body) was injected around the thyroid of a rhesus monkey, after which CT scans were used to visualize the liquid's fate and verify its safety.

RESULTS

The 51 patients with 10-40 mL injections and 116 patients with larger injections (45-450 mL) showed similar complete ablation rates (88.46% vs. 90.44%, p = 0.582), comparable 6-month VRR (82.79% vs. 76.62%, p = 0.079), and complication incidences, although the latter group had larger nodules (9.11 mL vs. 13.79 mL, p = 0.003), more energy delivered (3.44 kcal vs. 6.04 kcal, p < 0.001), and longer operation times (51.37 min vs. 69.2 min, p < 0.001). In the animal experiment, the 20 mL of liquid diffused quickly (within 10 min) from the vicinity of the thyroid to the mediastinum and retropharyngeal space. It was observed in the kidneys at 10 min and disappeared from the neck and chest space by 24 h.

CONCLUSIONS

Continuous, large-volume hydrodissection can protect the delicate structures around the thyroid throughout the RFA procedure and might be beneficial in large thyroid nodule ablation.

Efficacy and safety of single-session radiofrequency ablation for intrathoracic goiter: preliminary results and short-term evaluation

BACKGROUND

An intrathoracic goiter (ITG) is defined as a thyroid extension below the sternal notch. Compared to cervical goiters, surgery for ITG is more challenging, with a higher risk of an extracervical approach. Ultrasound (US)-guided radiofrequency ablation (RFA) is a minimally invasive treatment modality. The purpose of this study was to prospectively evaluate the safety and efficacy of RFA in patients with ITG.

METHODS

From a total of 324 patients who underwent thyroid RFA at a single medical center, 15 patients (mean age 52.2 years; 73.3% female) with 16 ITGs were included and classified into three grades and three types using the cross-section imaging CT system. Clinical features and demographics, degree of extension, RFA details, goiter volume, and complications were analyzed.

RESULTS

Mean pre- and post-RFA goiter volumes as measured by US were 106.62 ± 61.82 and 25.09 ± 14.22 mL respectively, with a volume reduction rate (VRR) of 75.5% (p < 0.001) at 6 months. The VRR as measured by CT/MRI was 57.0 ± 10.0% (p < 0.001) at 6 months. The intrathoracic length reduction rate at 6 months was 44.9 ± 39.2% (p = 0.001). In addition, 4 (25%) ITGs had total regression of the intrathoracic extension, with a downgrade from grade 1 to cervical goiter. Mean pre- and post-RFA symptom and cosmetic scores were 1.53 and 0.15 (p = 0.001), and 2.67 and 2.00 (p = 0.001), respectively. One patient had transient vocal cord palsy and another had perithyroidal and mediastinal hemorrhage.

CONCLUSION

US-guided RFA is an effective treatment for ITG in terms of both cervical and intrathoracic reductions with an acceptable complication rate.