A comparison of laser with radiofrequency ablation for the treatment of benign thyroid nodules: a propensity score matching analysis

Figures & data

Figure 1. The figure shows the operator’s role in determining the extent of nodule volume reduction using laser light (A) or radiofrequency energy (B).

Table 1. Baseline characteristics and results in all study patients according to baseline nodule volume group before propensity score matching.

	LA group nodule volume (ml)				RFA group nodule volume (ml)				p Value
	≤13 (n = 151)	13.1–30 (n = 195)	>30 (n = 103)	Total (n = 449)	≤13 (n = 35)	13.1–30 (n = 80)	>30 (n = 37)	Total (n = 152)	≤13 (n = 186)	13.1–30 (n = 275)	>30 (n = 140)	Total (n = 601)
Age (yrs)	55 ± 13	57 ± 14	58 ± 15	57 ± 14	53 ± 13	56 ± 13	65 ± 14	57 ± 14	0.410	0.611	0.028	0.526
Female	77%	67%	61%	69%	77%	66%	76%	71%	0.968	0.882	0.112	0.642
Baseline volume	7.4 ± 3.1	20.0 ± 4.7	45.1 ± 16.6	21.5 ± 16.5	9.9 ± 2.9	19.7 ± 4.7	49.0 ± 20.3	24.6 ± 17.9	<0.001	0.677	0.304	0.065
Volume reduction at 6th month (%)	−58 ± 19	−59 ± 19	−61 ± 17	−59 ± 18	−59 ± 25	−59 ± 19	−50 ± 19	−57 ± 21	0.791	0.960	0.003	0.210
Volume reduction at 12th month (%)	−62 ± 19	−62 ± 18	−64 ± 16	−63 ± 18	−69 ± 24	−63 ± 19	−56 ± 21	−62 ± 21	0.174	0.848	0.033	0.830
Total energy (kJ)^a	3.5 ± 1.9	6.6 ± 2.1	7.8 ± 2.3	5.8 ± 2.7	46.2 ± 30.2	59.6 ± 40.9	93.6 ± 92.6	64.6 ± 58.2	<0.001	<0.001	<0.001	<0.001
Ablation time (min)	11.9 ± 4.3	18.9 ± 5.3	21.7 ± 5.7	17.1 ± 6.4	14.2 ± 8.0	18.1 ± 10.6	26.9 ± 24.8	19.4 ± 15.5	0.111	0.680	0.221	0.086

Values are reported as mean ± SD.

^akJ: Kilojoules.

Table 2. Predictive factors for percentage volume reduction (PVR) at 6th month in all study patients and according to LA or RFA treatment before propensity score matching.

	All patients			LA group			RFA group
	PVR <50% (n = 161) 27%	PVR ≥50% (n = 440) 73%	p Value	PVR <50% (n = 114) 25%	PVR ≥50% (n = 335) 75%	p Value	PVR <50% (n = 47) 31%	PVR ≥50% (n = 105) 69%	p Value
Age (yrs)	55 ± 14	57 ± 14	0.193	55 ± 14	57 ± 14	0.087	58 ± 16	57 ± 13	0.871
Female (%)	74	68	0.160	75	67	0.140	72	70	0.815
Baseline volume	21.4 ± 17,2	22.6 ± 16.8	0.412	18.3 ± 13.5	22.6 ± 17.3	0.006	28.8 ± 22.3	22.7 ± 15.3	0.095
Total energy (kJ)^a	17.4 ± 33.8	21.8 ± 40.4	0.177	5.4 ± 2.6	6.0 ± 2.7	0.033	47.1 ± 52.4	72.3 ± 59.1	0.010
Ablation time (min)	15.5 ± 9,7	18.5 ± 9,5	0.001	16.2 ± 6.7	17.4 ± 6.3	0.101	13.6 ± 14.5	21.9 ± 15.3	0.002

Values are reported as mean ± SD.

^akJ: KiloJoules.

Figure 2. The figure shows the mean nodule reduction at 6 months according to baseline nodule volume group in all patients before (A) and after (B) propensity score adjustment. After propensity score-matching analysis, the higher rate of PVR in LA group in comparison with RFA group, appears confirmed in large nodules (>30 ml) thyroid nodules, appears clearly confirmed.

Table 3. Results in all study patients according to baseline nodule volume group after propensity score matching.

	LA group nodule volume (ml)				RFA group nodule volume (ml)				p Value
	≤13 (n = 34)	13.1–30 (n = 74)	>30 (n = 30)	Total (n = 138)	≤13 (n = 34)	13.1–30 (n = 74)	>30 (n = 30)	Total (n = 138)	≤13 (n = 68)	13.1–30 (n = 148)	>30 (n = 60)	Total (n = 276)
Volume reduction at 6th month (%)	−67 ± 22	−65 ± 17	−69 ± 19	−67 ± 19	−57 ± 25	−59 ± 19	−50 ± 21	−57 ± 21	0.071	0.026	0.001	<0.001
Volume reduction at 12th month (%)	−70 ± 22	−69 ± 18	−73 ± 18	−70 ± 19	−67 ± 24	−63 ± 19	−54 ± 23	−62 ± 22	0.646	0.047	0.001	0.001
Total energy (kJ)^a	4.0 ± 2.0	6.6 ± 2.2	7.1 ± 3.1	6.1 ± 2.7	44.8 ± 30.5	59.9 ± 41.0	88.0 ± 83.3	61.6 ± 51.4	<0.001	<0.001	<0.001	<0.001
Ablation time (min)	12.6 ± 4.8	18.9 ± 4.8	20.5 ± 7.3	17.7 ± 6.2	13.9 ± 8.1	18.2 ± 10.7	25.8 ± 21.8	18.7 ± 13.6	0.435	0.623	0.238	0.437

Values are reported as mean ± SD.

^akJ: Kilojoules.

Table 4. Major, minor complications and side effects in each group of 138 patients.

Type of complications (SIR Class)^a		Complications and side effects no. (%)^b time of detection								Time to recovery (days)		p
		Intra-procedural		Immediate post-procedural (within 24 h)		Peri-procedural (within 30 days)		Delayed (after 30 days)
		LA	RFA	LA	RFA	LA	RFA	LA	RFA	LA	RFA
Major
Voice change^c	(C)			4 (1.2)	3 (2.7)					28–84	2-permanent^d	NS
Hyperthyroidism	(C)								1 (0.6)			NS
Minor
Hematoma	(B)	3 (0.9)	5 (4.5)							5–10	5–10	0.044
Side effects
Pain	(A)
Mild		18 (5.5)	12 (10.9)									NS
Moderate		4 (1.3)^e								1–4		NS
Severe		2 (0.6)^e	1 (0.9)	2 (0.6)^f						1–3	1	NS
Vasovagal reaction	(A)	4 (1.2)										NS
Fever (37.5 °C–38.5 °C)	(A)	6 (1.8)								1–4		NS

^a Society of Interventional Radiology (SIR) guidelines criteria; Minor complications: A: No therapy, no consequence; B: Nominal therapy, no consequence; includes overnight admission for observation only. Major Complications: C: Require therapy, minor hospitalisation (<48 h); D: Require minor therapy, unplanned increase in level of care, hospitalisation >48 h; E: Permanent adverse sequelae; F: Death.

^bValue calculated per LA sessions.

^cTransient or permanent cord paralysis.

^dOne case with permanent stridor.

^eWith discomfort.

^fWith swelling.

Figure 3. The figure shows the wide variability in volume reduction with both the techniques according to baseline nodule volume, both before (A) and after (B) propensity score adjustment.