A propensity score matching study between ultrasound-guided percutaneous microwave ablation and conventional thyroidectomy for benign thyroid nodules treatment

Figures & data

Figure 1. US scans in a 57-year-old woman: (a) US scans showed that the largest diameter was 3.67 cm; (b) US scans showed that the two other perpendicular diameters were 2.46 cm and 2.28 cm, respectively. (c) Contrast-enhanced ultrasonography (CEUS) showed a cyst-solid mixed TN. The TN’s volume was 10.8 ml, of which the solid portion was 95.1%; the arrow highlights the central region of the TN.

Figure 2. The same patient as in Figure 1. (a) In the MWA procedure, the ‘hydrodissection technique’ was applied. The isolation zone is marked with an arrow in the figure. (b) MWA antenna could be visualized as a hyperechoic line in the MWA process under US. The area that surrounds the antenna also shows the hyperechoic region. (c) CEUS showed that approximately 99% of the TN had been ablated.

Table 1. Baseline characteristics of patients with TNs treated by US-guided PMWA and conventional thyroidectomy before and after matching.

Characteristics	Before matching			After matching
	WMA group (n = 156)	Traditional thyroidectomy group (n = 124)	p Value	MWA group (n = 106)	Traditional thyroidectomy group (n = 106)	p Value
Age (y)	36.7 ± 10.3	45.4 ± 11.2	.003	39.6 ± 9.3	45.4 ± 11.2	.056
Gender		>0.99		>0.99
Male	58 (56.5)	40 (33.6)		31 (29.5)	28 (27.6)
Female	98 (93.5)	84 (83.4)		75 (73.5)	78 (74.4)
Nodule diameter (mm)^a	28.2 (24.1–35.6)	26.3 (23.2–32.1)	.016	28.6 (24.1–35.3)	28.2 (23–35.9)	.56
Nodule volume (ml)^a	5.7 (3.8–10.3)	4.6 (3.4–8.5)	.067	5.7 (3.8–10.3)	5.5 (3.5–9.6)	.531
Symptoms score	4.1 ± 1.4	4.5 ± 1.3	.011	4.3 ± 1.4	4.5 ± 1.3	.389
Cosmetic score	3.2 ± 0.8	2.9 ± 0.8	.002	3.2 ± 0.8	3.0 ± 1.9	.478
Follow-up period (mo)	12.8 ± 5.8	12.6 ± 2.8	.086	12.8 ± 5.1	12.7 ± 2.8	.760

Conventional thyroidectomy group, patients treated with conventional thyroidectomy; MWA group, patients treated with US-guided PMWA. Except for Nodule diameter, Nodule volume and p values, data are reported as No.(%) or mean ± standard deviations.

^a Data are with skewed distribution and are reported as median with the inter-quartile range in parentheses and analyzed using Mann–Whitney U-test.

Figure 3. (a) A 61-year-old woman in the thyroidectomy group; the picture shows her early postoperative wound within a highly visible area; (b) The same patient as in Figures 1 and 2, the picture shows her cosmetic results of US-guided PMWA, where there is no obvious cervical scar in her neck.

Table 2. Operation results in the MWA and conventional thyroidectomy groups in a propensity-matched population of patients with TNs.

Groups	Operation time (min)	Blood loss (ml)	Complication rate(%)	Hospitalization (d)
MWA groups (n = 106)	28.6 ± 5.2	12.5 ± 2.0	1.9	1.6 ± 0.5
Traditional thyroidectomy
Group (n = 106)	80.2 ± 15.6	30.6 ± 4.3	6.6	4.3 ± 0.5
t(x^2) Value	t= −22.471	t= −24.608	x^2=0.451	t= −21.386
p Value	.000	.000	.389	.000

Conventional thyroidectomy group, patients treated with conventional thyroidectomy; MWA group, patients treated with US-guided PMWA. Except for t values and p values, data are reported as No.(%) or mean ± standard deviations.

Table 3. Serum Concentrations of CRP in the MWA and conventional thyroidectomy groups in a propensity-matched population of patients with TNs (mg/L).

Groups	One day before operation	12 hours after operation	t Value	p Value
MWA groups (n = 106)	0.6 ± 0.2	0.7 ± 0.1	−1.112	.101
Conventional thyroidectomy group (n = 106)	0.6 ± 0.18	12.0 ± 1.9	−15.228	.000
t(x^2) Value	−3.016	−15.892
p Value	.638	.000

Conventional thyroidectomy group, patients treated with conventional thyroidectomy; MWA group, patients treated with US-guided PMWA. Except for T values and p values, data are reported as No.(%) or mean ± standard deviations.

Table 4. Serum Concentrations of IL-6 in the MWA and conventional thyroidectomy groups in a propensity-matched population of patients with TNs (ng/L).

Groups	One day before operation	12 hours after operation	t Value	p Value
MWA groups (n = 106)	3.5 ± 1.3	3.6 ± 1.2	−1.829	.056
Conventional thyroidectomy group (n = 106)	3.5 ± 1.2	14.2 ± 4.5	−13.220	.000
t(x^2) Value	−0.462	−15.889
p Value	.654	.000

Conventional thyroidectomy group, patients treated with conventional thyroidectomy; MWA group, patients treated with US-guided PMWA. Except for t values and p values, data are reported as No.(%) or mean ± standard deviations.

Table 5. Serum Concentrations of TNF-α in the MWA and conventional thyroidectomy groups in a propensity-matched population of patients with TNs (mg/L).

Groups	One day before operation	12 hours after operation	t Value	p Value
MWA groups (n = 106)	35.6 ± 5.2	42.2 ± 5.9	−12.512	.000
Conventional thyroidectomy group (n = 106)	37.2 ± 2.1	50.1 ± 2.8	−20.825	.000
t(x^2) Value	−2.712	−7.829
p Value	.008	.000

Conventional thyroidectomy group, patients treated with conventional thyroidectomy; MWA group, patients treated with US-guided PMWA. Except for t values and p values, data are reported as No.(%) or mean ± standard deviations.

Table 6. Treatment results in the MWA group in a propensity-matched population of patients with TNs.

Time	Volume (cm^3)	VRR (%)
Before ablation	2.50 (0.30–5.00)	–
1 month after ablation	2.12 (1.21–2.79)	15.2
3 months after ablation	1.31 (0.89–1.91)	47.6
6 months after ablation	0.82 (0.32–1.21)	67.2
12 months after ablation	0.51 (0.00–1.00)	79.6

Conventional thyroidectomy group, patients treated with conventional thyroidectomy; MWA group, patients treated with US-guided PMWA. Data are reported as No.(%).

Figure 4. US scans in a 30-year-old woman: (a) US reveals a cyst-solid mixed TN. The TN’s volume was 4.1 ml, of which the solid portion was 83.6%. (b) One month after the ablation, the volume of the TN decreased to 2.5 ml with a VRR of about 39.6%. (c) Three months after US-guided PMWA, the volume was 1.2 ml, with a VRR of about 73.8%. (d) Twelve months after US-guided PMWA, the volume was 0.03 ml with a VRR of about 97.6%.