A preliminary study of microwave ablation for solitary T1N0M0 papillary thyroid carcinoma with capsular invasion

Figures & data

Figure 1. (A) 42-year-old woman with papillary thyroid cancer with capsular invasion (CI) was treated with microwave ablation (MWA). (A) pre-MWA, ultrasound(US) showed a hypoechoic target tumor (arrows) with CI (triangles); (B) before MWA, contrast-enhanced US (CEUS) showed a hypo-enhancement pattern in the artery phase (arrows); (C) the hydrodissection technique (triangles) was used to protect the surrounding structures (arrows); (D) US showed a hyperechoic pattern in the tumor (arrows) during ablation; (E) post-MWA, CEUS showed no enhancement (arrows) in the tumor area; and (F) on one-month post-MWA, US showed a hypoechoic ablation zone (arrows).

Figure 2. Flow chart of patient selection.

Figure 3. Changes in mean volume at each follow-up.

Table 1. Demographic characteristics of PTC with CI included in this study (n = 69).

Variables	Total
Age (years)*	45.55 ± 11.82
Male	18 (26%)
Female	51 (74%)
Follow-up (months)*	26 ± 10
Ablation time (s)*	125 ± 71
Volume for hydrodissection	54 ± 17 ml
Tumor stage
T1a	54(67%)
T1b	15(33%)
BRAF V600E mutation
Positive	59 (85.5%)
Negative	5 (7.2%)
Lack of data	5 (7.2%)

Unless indicated otherwise, data are presented as frequencies (percentage). *Data presented as mean ± standard deviation (range). CEUS, contrast-enhanced ultrasound.

Table 2. Tumor size (maximum diameter and volume) before MWA and at each follow-up time-point after MWA.

Follow-up time	Maximum diameter (cm)	P value	Volume (ml)	P value	Mean volume reduction rate	P versus last follow-up
Before MWA (n = 69)	0.84 ± 0.39	NA	0.26 ± 0.35	NA	NA	NA
After MWA
1-month (n = 69)	1.65 ± 0.52	.000	1.40 ± 1.68	.000	−10.70 ± 19.55	NA
3-month (n = 69)	1.30 ± 0.47	.000	0.75 ± 1.11	.000	−5.53 ± 13.71	.000
6-month (n = 69)	1.02 ± 0.48	.000	0.40 ± 0.78	.000	−2.75 ± 9.85	.000
9-month (n = 69)	0.72 ± 0.56	.000	0.26 ± 0.73	.000	−1.17 ± 7.67	.000
12-month (n = 65)	0.45 ± 0.56	.000	0.19 ± 0.74	.000	−0.64 ± 7.88	.000
18-month (n = 58)	0.27 ± 0.46	.000	0.13 ± 0.52	.000	−0.06 ± 5.32	.000
24-month (n = 44)	0.23 ± 0.45	.016	0.13 ± 0.54	.000	0.13 ± 4.83	.004
30-month (n = 29)	0.14 ± 0.45	.027	0.13 ± 0.57	.007	0.12 ± 5.34	.025
36-month (n = 22)	0.12 ± 0.39	.180	0.13 ± 0.47	.018	0.14 ± 4.13	.109
42-month (n = 9)	0.00 ± 0.00	1.000	0.00 ± 0.00	.180	1.00 ± 0.00	.180
48-month (n = 2)	0.00 ± 0.00	1.000	0.00 ± 0.00	1.00	1.00 ± 0.00	1.000

Figure 4. Changes in VRR at each follow-up.

Table 3. Demographic characteristics of cases with or without tumor progression in the present study.

Variables	Without tumor progression (n = 64)	With tumor progression (n = 5)	p value
Age (years)	45.59 ± 11.59	45.00 ± 16.16	0.18
Sex (M/F)	16/48	2/3	0.46
Tumor stage
T1a/T1b	49/15	5/0	0.76
Nodule diameter (cm)	0.84 ± 0.40	0.86 ± 0.26	0.41
Nodule volume (ml)	0.25 ± 0.36	0.24 ± 0.19	0.53
BRAF
Positive/Negative	54/5	5/0	0.49
Thyroid capsule (invaded/not invaded)
Anterior capsule	30/34	5/0	0.07
Lateral capsule	21/43	0/5	0.30
Medial capsule	19/45	0/5	0.36
Posterior capsule	19/45	0/5	0.36
Ablation time (s)	144.94 ± 82.79	120.20 ± 44.20	0.28

M: male; F: female. Except for sex (M/F), T1a/T1b, BRAF, Thyroid capsule (invaded/not invaded) and p-values, data are reported as mean ± standard deviations.

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.