Endocrine Abstracts

Objectives: Assess the response of benign thyroid nodules to HIFU treatment depending on their volume and localization. Know if the treatment is painful when sedation is not used.

Methods: 66 patients with benign thyroid nodules (Bethesda Category II) were treated with HIFU (Echopulse Theraclion). They were grouped in 3 categories by maximal nodule diameter as assessed by echography. Group 1: nodule diameter between 14 and 20 mm; Group 2: between 21 and 30 mm; Group 3: over 30 mm. Follow-up at 8 weeks, 6, 12 and 18 months was done under echography. Nodules are described as superficial or deep taking the center line of the trachea as a reference. We define therapeutic success when the nodule size, after 8 weeks of the last treatment, is inferior to 50% of its initial size. All patients followed the same pre-treatment oral analgesia protocol: Lorazepam 1 mg + Paracetamol 1.000 mg + Dexketoprofene 25 mg. Assessment was made using a categorical 6-grade scale (CS).

Results: Results from groups 1 and 2 are significantly different from those from Group 3. 81% of Group 1 cases reach therapeutic success with a single treatment. Groups 2 and 3, have respectively 58% and 42% of success. In cases from Groups 2 and 3 treatment is repeated up to 4 times. Deeper nodules and nodules located on the isthmus can only be treated partially. There has been no recurrence or enlargement of treated nodules after 18 months. Patients describe pain as ‘tolerable’ in 68% of cases. In 23% of cases pain is marked as ‘almost intolerable’, which needed to lower the delivered power by 5–10 W. Lastly, in 9% of cases pain was marked as ‘intolerable’ leading the treatment to finalize without being totally performed. Pain sensitivity is less and less tolerated for Group 3 nodules of longer treatment durations, as oral analgesia efficacy decreases in time.

Conclusions: The treatment of benign thyroid nodules with HIFU is safe and effective. The size of thyroid nodules is an important factor to design of the treatment strategy with HIFU. Nodules under 30 mm diameter are the best choice in terms of treatment speed, efficacy and obtained results. For bigger nodules, several sessions and a follow-up over 18 months are necessary to obtain satisfactory results. Deeper nodules and nodules located on the isthmus need a previous simulation treatment to assess the expected reduction. Our protocol for oral analgesia is successful for nodules that do not require long treatment times, and on patients that feel relaxed and have a better self-control management.