Ultrasound-guided percutaneous radiofrequency ablation for benign thyroid nodules

4.1 In a systematic review of 284 patients with benign thyroid nodules treated by radiofrequency ablation (RFA), the mean nodule volume reduced by 9.8 ml after the procedure (95% confidence interval [CI] −13.83 to −5.72; 9 studies, n=284 nodules; I²=98% [significant heterogeneity]). In a randomised controlled trial (RCT) of 84 patients with benign solid thyroid nodules, the mean nodule volume reduced from 24.5(±19.6) ml at baseline to 8.6(±9.5) ml at 6‑month follow‑up (p<0.001) in patients treated by RFA, compared with no volume reduction in patients randomised to no treatment (27.5±22.1 ml at baseline and 27.8±22.1 ml at 6‑month follow‑up). In an RCT of 80 patients with solid, compressive, non‑functioning benign thyroid nodules treated by RFA or no treatment, the median percentage volume changes were 71% reduction and 3% increase respectively (p=0.0001). In a non‑randomised comparative study of 400 patients with nodular goitre treated by RFA or surgery there was a mean percentage volume reduction of 85(±17.1)% after RFA at 12‑month follow‑up (p=0.002). In a case series of 111 patients with benign, non‑functioning thyroid nodules there was a mean volume reduction of 91(±15.8)% after RFA at 3‑year follow‑up. In an RCT of 50 patients with a single benign cystic thyroid nodule treated by RFA or ethanol ablation (also included in the systematic review), there were median percentage volume reductions of 93(±5.4)% and 97(±4.1)% respectively at 6‑month follow‑up (p value not reported). In a second RCT of 50 patients with predominantly cystic thyroid nodules treated by RFA or ethanol ablation, mean volume reductions were 87.5(±11.5)% and 82.4(±28.6)% respectively at 6‑month follow‑up (p=0.710).

4.2 In the systematic review of 284 patients there was a reduction in the mean symptom score (measured on a 10‑point visual analogue scale, with lower scores indicating less severe symptoms) of 2.89 after RFA (95% CI −2.51 to −3.28; 4 studies, n=85; I²=56%). In the RCT of 84 patients the mean pressure symptom score (measured on a 10‑point visual analogue scale, with lower scores indicating less severe symptoms) reduced from 2.8(±3.3) at baseline to 0.4(±0.8) at 6‑month follow‑up (p<0.001) in patients treated by RFA compared with no reduction for patients with no treatment (2.7±3 at baseline and 2.9±3.2 at 6‑month follow‑up). In the RCT of 80 patients the symptom score (on a scale of 0 to 10, with lower scores indicating less severe symptoms) was 0.4(±0.7) for patients treated by RFA compared with 3.3(±1.7) for patients with no treatment (p=0.0001) at 6‑month follow‑up. In the case series of 111 patients, the symptom score (assessed on a scale of 0 to 10, with lower scores indicating less severe symptoms) reduced from 4.3(±1.6) at baseline to 0.8(±0.9) at last follow‑up (mean follow‑up 49 months, p<0.001). In the RCT of 50 patients treated by RFA or ethanol ablation (also included in the systematic review) symptom scores (assessed on a scale of 0 to 10, with lower scores indicating less severe symptoms) were 0.5(±0.8) and 0.5(±0.7) respectively at 6‑month follow‑up (p=0.806).

4.3 In the systematic review of 284 patients the mean reduction in cosmetic score (scored by a physician from 1 to 4, with lower scores indicating better cosmetic appearance) was 2.02 (95% CI −1.69 to −2.35; 5 studies, n=114; I²=78%) after RFA. In the RCT of 84 patients the mean cosmetic score (assessed on a scale of 1 to 4, with lower scores indicating better cosmetic appearance) reduced from 2.6(±0.9) at baseline to 1.7(±0.7) at 6‑month follow‑up (p<0.001) in patients treated by RFA, compared with no reduction for patients with no treatment (2.6±1.0 at baseline and at 6‑month follow‑up). In the RCT of 80 patients cosmetic scores (assessed on a scale of 1 to 4, with lower scores indicating better cosmetic appearance) were 1.7(±0.8) for patients treated by RFA and 3.5(±0.7) for patients with no treatment (p=0.0001) at 6‑month follow‑up. In the case series of 111 patients the cosmetic score (on a scale of 1 to 4, with lower scores indicating better cosmetic appearance) reduced from 3.2(±0.8) at baseline to 1.3(±0.6) at last follow‑up (mean follow‑up 49 months, p<0.001). In the RCT of 50 patients treated by RFA or ethanol ablation (also included in the systematic review) cosmetic scores (on a scale of 1 to 4, with lower scores indicating better cosmetic appearance) were 1.1(±0.4) and 1.2(±0.4) respectively at 6‑month follow‑up (p=0.682).

4.4 In the systematic review of 284 patients, 60 patients with 'hot' nodules were given methimazole at doses sufficient to maintain thyroid‑stimulating hormone within the normal range before RFA treatment. After RFA treatment, 29 patients continued to need some dose of this medication to maintain euthyroidism based on thyroid‑stimulating hormone measurements and symptoms (odds ratio 40.34, 95% CI 7.78 to 209.1; 3 studies, n=60; I²=2%).

4.5 In the non‑randomised comparative study of 400 patients, no patients treated by RFA needed medication for hypothyroidism compared with 71.5% of patients treated by surgery (p=0.002).

4.6 In the case series of 111 patients (126 nodules) the overall recurrence rate (defined as increases in nodule volume of greater than 50% compared with previous ultrasound images at a minimum of 3 years of follow‑up) was 6% (7/126). All nodules were benign on repeat fine‑needle aspirate biopsy. Four of the recurrent nodules decreased in size after repeat RFA, 2 were treated with repeat RFA without further follow‑up and 1 patient chose not to have further treatment and was lost to follow‑up.

4.7 The specialist advisers listed key efficacy outcomes as reduction in thyroid nodule volume, and improvement in compression symptoms and cosmetic appearance.