Effectiveness of minimally invasive methods (laser-induced interstitial thermotherapy and percutaneous ethanol sclerotherapy) in the treatment of Plummer’s disease

Abstract

Background. The purpose of the study was to investigate the effectiveness of minimally invasive methods, such as laser-induced interstitial thermotherapy (LITT) and its combination with percutaneous ethanol ablation (PEA), in treating toxic thyroid adenomas. To determine the multiplicity of the LITT procedure and parameters of laser radiation to achieve a stable positive therapeutic effect. Materials and methods. Between 2020 and 2024, 24 patients with Plummer's disease who did not receive previous thyrostatic therapy before the LITT session were treated and were divided into 2 groups. Patients of the first group with a predominantly parenchymal structure of the node received LITT monotherapy (16 patients), patients of the second group with an existing cystic component received percutaneous ethanol sclerotherapy followed by LITT (8 patients). Patients underwent ultrasound and hormonal follow-up after laser ablation at 2, 4, and 6 months. Study endpoints: percent nodal volume reduction compared to pretreatment volume (VRR), thyroid-stimulating hormone (TSH), free thyroxine, free triiodthyronine, TSH-receptor antibodies. Results. All patients had a positive result of treatment. The average nodal volume reduction ratio (VRR) for patients in the first group was 88.3 ± 7.9 % (min — 71.5, max — 95.4), and for patients in the second group — 72 % (min — 59.5, max — 85.4). The percen­tage of patients in whom the euthyroid status was recorded after the first session ranged from 100 % for nodes of smaller volume (up to 4 cm3) to 63 % for nodes of maximum volume (up to 13 cm3). After the completed treatment (the maximum number of LITT sessions — 4), all patients had a stable euthyroid status. The effective specific ener­gy for solid nodules is ≈ 900 J/ml, for mixed cystic-parenchymal nodules the specific energy is lower and ≈ 790 J/ml (for the volume of the nodule after PEA). Complications: one case of bleeding was recorded, and a moderate pain syndrome: 6 points on the Visual Analog scale. Conclusions. Laser thermal ablation of toxic thyroid adenomas under ultrasound guidance offers an additional safe and effective minimally invasive treatment option. Reduction of solid thyroid nodules is effective over time if the specific energy exceeds 900 J/ml (for the primary nodule volume). The reduction of mixed cystic-parenchymal nodules is effective under the condition of the effectiveness of ethanol, the specific energy for such nodules is less than ≈ 790 J/ml (for the volume of the nodule after PEA). The total energy for the course of treatment should not be less than the calculated (Е∑ ≈ Espec × Vnode). Clinical outcomes are significantly more favorable in small toxic adenomas than in large nodes