Efficacy and safety of single-session radiofrequency ablation for benign thyroid nodules of different sizes: a retrospective study

Figures & data

Figure 1. Consort diagram of the study.

Table 1. Patient and nodule characteristics based on nodule volume.

Characteristic	Total	Small (<10 ml)	Medium (10 ∼ 30 ml)	Large (>30 ml)	p-Value
Number of patients	136	48	44	44
Age Median	44.9 ± 11.8	44.7 ± 11.7	42.5 ± 11.9	47.7 ± 11.4	.123
Sex, female/male	109/27	37/11	35/9	37/7	.697
Laboratory studies (mean ± SD)
Serum T4 (ng/dl)	1.3 ± 0.8	1.2 ± 0.2	1.5 ± 1.25	1.27 ± 0.60	.264
Serum T3 (ng/dl)	98.8 ± 24.2	97.3 ± 21.4	97.0 ± 21.4	102.2 ± 32.3	.225
Serum TSH (uIU/ml)	1.6 ± 1.4	1.8 ± 1.3	1.6 ± 1.7	1.3 ± 1.0	.360
Technical characteristics
Delivered energy (Kcal)	7.1 ± 6.24	2.4 ± 1.6	6.5 ± 4.0	17.9 ± 6.8	<.001
Energy/ml^a (Kcal/cm^3)	0.41 ± 0.41	0.66 ± 0.58	0.35 ± 0.16	0.19 ± 0.10	<.001
Ablation time (minutes)	16.9 ± 8.9	10.3 ± 4.6	18.0 ± 7.1	23.2 ± 9.2	<.001
Electrode active tip					<.001
5mm	22	19	2	1
7mm	54	24	24	6
10 or 15mm	60	18	18	37

^a Energy/ml: The energy delivered per milliliter of the pretreatment nodule volume.

Figure 2. Changes in nodular volume and VRR of the three volume groups of BTN at each follow-up. Changes in nodular volume (A) and VRR (B) of the different echogenicity groups of BTN at each follow-up. BTN: benign thyroid nodule; VRR: volume reduction ratio.

Table 2. Outcomes based on nodule volume^a.

	Total (n = 136)	Small (<10 ml, n = 48)	medium (10 ∼ 30 ml, n = 44)	large (>30 ml, n = 44)	Group * time effect p-value^c
Nodule volume (Mean ± SD, ml)					<.001
Baseline	31.9 ± 39.1	4.9 ± 2.8	18.4 ± 5.8	75.0 ± 43.0
1 month	15.8 ± 17.2	3.0 ± 2.19	10.7 ± 4.7	34.3 ± 15.8
3 months	11.5 ± 18.3	1.9 ± 1.7	7.1 ± 3.6	26.0 ± 26.2
6 months	8.1 ± 1.3	1.3 ± 1.5	5.8 ± 3.7	17.9 ± 12.8
Time Effect p-value^b	<.001	<.001	<.001	<.001
Volume reduction ratio (Mean ± SD, %)					<.001
1 month	40.4 ± 3.3	28.9 ± 41.9^d,e	41.9 ± 19.1^d,f	51.3 ± 19.4^e,f
3 months	61.7 ± 19.9	57.4 ± 26.8^g,h	61.2 ± 14.6^g,i	66.6 ± 14.5^h,i
6 months	72.2 ± 17.3	71.7 ± 22.0^j,k	69.0 ± 16.4^j,l	72.2 ± 17.3^k,l
Time Effect p-value	<.001	<.001	<.001	<.001
Cosmetic Score (0-3)					p-value
Baseline	2.2 ± 1.1	1.4 ± 1.2	2.5±.9	2.9±.4	<.001
6 months	.7±.9	.2±.4	.8±.8	1.3 ± 1.0	<.001
Time Effect p-value	<.001	<.001	<.001	<.001
Symptoms Score (0–5)					p-value
Baseline	1.1 ± 1.0	.8 ± .9	1.2 ± 1.1	1.3 ± 1.0	.02
6 months	.02±.13	.0±.0	.0±.0	.05±.2	.364
Time Effect p-value	<.001	<.001	<.001	<.001
Complications					p-value
Vocal palsy	6	1	1	3
Burn	1	0	1	0
Hematoma	1	0	0	1
Rupture	2	0	0	1
Total	8	1	2	5	.061

^aGeneralized estimation equation analysis was used for repeated measure analysis for volume change and volume reduction ratio at different time outcomes.

^bTime effect defined as volume differences of the same group between different time. The baseline measurement were the reference categories.

^cGroup x time effect defined as change of volume for different volume group at 6 months.

Group effect was defined as group differences at the same time between different nodule volume groups, ^dp = .012; ^ep = <.001; ^fp = .043; ^gp = .510; ^hp < .067; ⁱp = .249; ^jp = .556; ^kp < .319; ^lp = .121.

Figure 3. Goiter rupture before and after RFA. Ultrasound and CT obtained after nodular rupture of the patient with previous partial thyroidectomy history and received thyroid RFA. (A) Incomplete anterior thyroid capsules surrounding the thyroid nodule noted before RFA. (B)The incomplete capsule site is afterward the nodular rupture site on sonography. (C) Post-contrast CT scan shows a ruptured nodule into the right anterior neck. RFA: radiofrequency ablation.