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Abstract: Minimalistic management options such as active surveillance and thyroid lobectomy are increasingly being accepted as reasonable management options for properly selected patients with low-risk papillary thyroid cancer. Leveraging technologies developed for the treatment of benign thyroid nodules, ultrasound-guided percutaneous thermal ablation is now being evaluated as a potential additional minimalistic management option for small, intrathyroidal, low-risk papillary thyroid cancer. Published retrospective data on more than 5000 low-risk papillary thyroid cancer patients treated with thermal ablation indicate that with appropriate training and proper patient selection, these technologies can be safely and effectively applied to papillary microcarcinomas. When compared to immediate surgery, thermal ablation appears to have lower complication rates with similar short-term rates of recurrence. Proper patient selection is facilitated by the use of a clinical framework which integrates imaging characteristics, patient characteristics, and medical team characteristics to classify a patient as ideal, appropriate, or inappropriate for minimalistic management options (active surveillance, thyroid lobectomy, or thermal ablation). While retrospective in nature and lacking randomized prospective clinical trial data, currently available data do support the proposition that thermal ablation technologies reliably destroy papillary thyroid microcarcinoma lesions and are associated with clinically acceptable oncologic outcomes when done by experienced teams in properly selected patients.

Background: To compare laser ablation (LA) zone dimensions at two predetermined energy parameters to cover a theoretical 10 mm zone + 2 mm margin in a thyroid swine model., Methods: Approval of the Institutional Animal Care and Use Committee was obtained. After hydrodissection, an ultrasound-guided LA (Elesta Echolaser X4 with Orblaze technology, 1064 nm) was performed in the periphery of the thyroid in 10 swine. Two cohorts were established to ablate a region of 10mm diameter with 2mm margin based on manufacturer's ex vivo data (n= 5 at 3W/1400J and n= 5 at 3W/1800J). The ablation zone was measured on contrast-enhanced computed tomography (CT) and compared to the pathological specimen. Euthanasia was performed 48 hours following ablation., Results: All ablations in the 3W/1800J group achieved a diameter of 12 mm ± 1 mm in three dimensions. In the 3W/1400J group, 1 ablation reached 12 mm ± 1 mm in 2 dimensions and 4 ablations reached this size in one dimension. Maximum diameter was higher in the 3W/1800J compared to the 3W/1400J group, both on histology (1.46 cm ± 0.05 vs. 1.1 cm ± 0.0, p< 0.01) and CT (1.52 cm ± 0.04 vs. 1.18 cm ± 0.04, p< 0.01). Similar results were obtained regarding volumes, both on histology (1.12 mL ± 0.13 vs. 0.57 mL ± 0.06, p< 0.01) and CT (1.24 mL ± 0.13 vs. 0.59 mL ± 0.07, p< 0.01). Histology showed coagulation necrosis and correlated well with CT measurements., Conclusion: Optimal parameters to obtain a LA zone of 10 mm with 2 mm margin utilizing a single needle are 3W/1800J., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE).)

Image-guided ablation is performed by percutaneously introducing ablation probes to deliver energy into a tumor to destroy it in a controlled and localized fashion. Ablation modalities can be broadly classified as thermal or non-thermal based on the mechanism of tumor destruction and are performed using different types of image guidance for planning, delivering and follow-up of the treatment. Ablation is performed in a minimally invasive fashion, providing greater residual organ preservation with minimal morbidity to the patient. Image-guided ablation is being used in the clinic for the treatment of primary and metastatic tumors, and this article reviews state of the art for the treatment of malignancies in the liver, lung, kidney and musculoskeletal tissue., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)