High-intensity focused ultrasound (HIFU) therapy for benign thyroid nodules: a 3-year retrospective multicenter follow-up study

Abstract

Background

Outcomes of high-intensity focused ultrasound (HIFU), as a non-surgical treatment option for benign symptomatic thyroid nodules, has mainly been based on single-center studies and short-term follow-up. Therefore, we assessed the safety, and long-term efficacy of HIFU in benign thyroid nodules among four centers with expertise in thyroid mini-invasive procedures.

Patients and methods

Retrospective three year follow-up study in four European centers, treating solid benign thyroid nodules causing pressure symptoms and/or cosmetic concerns. Nodule volume reduction was assessed at 1, 3, 6, 12, 24, and 36 months post-treatment. Technical efficacy, defined as a volume reduction rate (VVR) >50% was evaluated at 6, 12, 24 and 36 months. Predictive factors of efficacy were assessed using logistic models. Complications and side effects were classified according to the Interventional Radiology Guidelines and changes in local symptoms were scored on a visual-analog scale.

Results

Sixty-five patients (mean age 51.1 ± 14.0 years; 86.2% women) with a single thyroid nodule and a mean baseline nodule volume of 9.8 ± 10.3 mL were treated with a mean energy of 7.1 ± 3.1 kJ (range: 2.0 to 15.5 kJ). Median nodule volume reduction was 31.5% (IQR: −38.6% to −23.1%) at 12 months and 31.9% (IQR: −36.4% to −16.1%) at 36 months. Technical efficacy was obtained in 17.2% of cases at 6 months, 17.8% at 12 months, 3.4% at 24 months, and 7.4% at 36 months. The number of treated pixels and the mean energy delivered were positively correlated to VRR at 1, 6 and 12 months. The risk of treatment failure decreased by 4.3% for each additional unit of energy delivered. The procedure duration was inversely correlated with treatment failure (OR 1.043, 95% CI: 1.011–1.083; p = 0.014). Improvement of cervical pressure symptoms or cosmetic complaints were observed in less than 15% of the cases at 12, 24 and 36 months. Horner’s syndrome occurred in one case (1.5%) and minor complications, not requiring treatment, in three (4.6%) patients. No change in thyroid function was registered.

Conclusions

HIFU carried a low risk of complications. A single treatment resulted in a 30–35% thyroid nodule volume decrease within one year, reduction that remained stable for 2 years. Outcomes varied significantly between centers with different HIFU expertise. Focus on improved HIFU technology, adequate training, and appropriate selection of patients is needed to achieve efficacy comparable to other thermal ablation procedures.

Keywords:

• Benign thyroid nodule
• minimally invasive treatment
• thermal ablation
• high-intensity focused ultrasound ablation (HIFU ablation)
• thyroid hormones
• thyroid function

Acknowledgements

We are indebted to Mr. François MACHURON for helping with the statistical analysis.

Ethical approval

The research was carried out in accordance with the World Medical Association Declaration of Helsinki. The Institutional Bioethics Committees of each center approved the study.

Authors’ contributions

HM, ABH and EP wrote the first version of the manuscript. ABH, AP, GB, AB, RG, BR, DT, DB and EP collected the data. ABH and FM performed and validated the statistical analysis. LH and all authors critically reviewed the paper and approved the final version of the manuscript.

Disclosure statement

Hervé Monpeyssen has previously consulted for Theraclion and Starmed (oral conference communication). Édouard Ghanassia has previously consulted for Ablatech. Laszlo Hegedüs is a former consultant and scientific board member for Theraclion. The other authors have nothing to disclose regarding this paper.

None of the above companies have had any influence on any aspect of this manuscript.

Any grants or fellowships supporting the writing of the paper: None.