Efficacy and safety of microwave ablation for cervical metastatic lymph nodes arising post resection of papillary thyroid carcinoma: a retrospective study

Figures & data

Figure 1. A 47-year-old woman who had undergone a total thyroidectomy 2 years ago for papillary thyroid cancer underwent microwave ablation (MWA) of cervical metastatic lymph nodes (LN). A, Pre-MWA, B-mode ultrasonography (US) showed hypoechoic LN (arrow); B, Fine-needle aspiration biopsy (FNAB) process of the LN (arrow); C, Pre-MWA, the contrast-enhanced US (CEUS) showed uneven and highly enhanced patterns (arrow); D, Spacer fluid (arrow) was injected to surround the LN; E, Hyperechoic (arrow) pattern in the LN during MWA; F, Post-MWA, the CEUS showed no enhancement (arrow) in LN.

Table 1. Clinical characteristics of the study population.

Patient	Sex	Age	Primary tumor location	Type of operation	Postoperative Radioiodine therapy	No. of metastatic LN	Duration between surgery and MWA (Y)	Duration of follow-up post-MWA (M)
1	F	52	R	Subtotal	No	1	6.6	36
2	F	49	R	Total	Yes	2	4.3	36
3	M	73	L	Partial /Total	No	2	37.9/2.4	36
4	M	50	R	Total	Yes	2	3.1	36
5	F	65	R	Total	No	1	1.9	24
6	F	36	L	Total	Yes	1	6.2	24
7	F	40	L	Subtotal/Total	No	6	5.4/3.4	24
8	F	54	R	Subtotal	No	4	4.5	24
9	F	37	R	Total	No	7	2.1	18
10	M	38	I	Total	Yes	2	2.5	18
11	F	47	L	Subtotal	No	2	2.9	18
12	F	28	L	Total	No	2	1.1	12
13	F	41	R	Total	Yes	2	3.0	12
14	F	47	R	Total	Yes	4	2.0	12

M: male; F: female; L: left; R: right; I: isthmus; Y: year; M: month.

Table 2. Characteristics of cervical metastatic lymph nodes.

Characteristics	N (%)
Left and right neck
Left	23 (60.5)
Right	15 (39.5)
Location
Level I	2 (5.3)
Level II	3 (7.9)
Level III	12 (31.5)
Level IV	15 (39.5)
Level VI	6 (15.8)
Pre-ablation maximum diameter (mm)
Range	4–48
Median	11.5
Interquartile range	9.8–14.0
Pre-ablation volume (mm^3)
Range	33.5–30144.0
Median	251.2
Interquartile range	154.4–408.7
Ablation time (seconds)
Range	10–685
Median	29
Interquartile range	20–49
Pre-ablation CEUS enhancement patterns
High-enhancement	25 (65.8)
Iso-enhancement	8 (21.1)
Low-enhancement	5 (13.1)

Table 3. Changes in cervical metastatic lymph nodes post-ablation at each follow-up.

Follow-up time (n)	Largest diameter (mm)	p value	Volume (mm^3)	p value
Pre-thermal ablation (38)	11.5 (9.8–14.0)	-	251.2 (154.4–408.7)	-
3-month post-thermal ablation (38)	9.5 (8.0–11.3)	<.001	206.7 (116.6–332.4)	<.001
6-month post-thermal ablation (38)	9.0 (0–10.3)	<.001	167.2 (0–293.1)	<.001
9-month post-thermal ablation (38)	8.0 (0–10.3)	<.001	166.2 (0–266.9)	<.001
12-month post-thermal ablation (38)	8.0 (0–10.0)	<.001	155.7 (0–236.8)	<.001
18-month post-thermal ablation (29)	8.0 (3–11.0)	<.001	153.9 (47.1–249.1)	<.001
24-month post-thermal ablation (19)	7.0 (0–9.0)	<.001	153.9 (0–226.1)	<.001
36-month post-thermal ablation (7)	6.0 (6.0–8.0)	.016	113.1 (94.2–167.5)	.018

N: number of lymph nodes. The largest diameter and volume are expressed as median (Interquartile range).

p value: post-ablation (3, 6, 9, 12, 18, 24, and 36 months) vs. pre-ablation, respectively.