Long-term results of radiofrequency ablation for locally recurrent papillary thyroid carcinoma

Figures & data

Figure 1. Recurrent papillary thyroid cancer at left level 3 after thyroidectomy and RI therapy in a 35-year-old female. (a) Transverse ultrasound image showing a 0.7-cm-sized hypoechoic mass at right level 6 (arrows). (b) An internally cooled electrode with a 1.5-cm-sized active tip was inserted into the recurrent tumor (arrows). (c) One month after RFA, the US scans showed the treated tumor had decreased with 79% VRR (d). Six months after RFA, the treated tumor was not found on US. RI: radioactive iodine; RFA: radiofrequency ablation; US: ultrasound.

Table 1. Patient baseline characteristics.

Patient characteristics	N = 32 (%)
Male/Female	13/19
Age^a (year, range)	44.63 ± 11.22 (21–67)
Family history of cancer
Yes	4 (12.5)
No	28 (87.5)
Surgical treatment
Total thyroidectomy	23 (71.88)
Subtotal thyroidectomy	7 (21.87)
Thyroid lobectomy	2 (6.25)
T
T1	12
T2	4
T3	2
N
N0	2
N1	16
M
M0	0
M1	0
NA^b	17
Lymph node dissection	29 (90.63)
Yes	29 (90.63)
No	3 (9.37)
Radioactive iodine therapy	21 (65.63)
Yes	21 (65.63)
No	11 (34.37)
Follow-up time^a (month, range)	73.19 ± 12.68 (60–98)

^aData are expressed as mean ± standard deviation.

^bNA: not available.

Figure 2. Changes in the largest diameter before RFA and at each follow-up. RFA: radiofrequency ablation.

Figure 3. Changes in tumor volume before RFA and at each follow-up. RFA: radiofrequency ablation.

Figure 4. Changes in VRR before RFA and at each follow-up. RFA: radiofrequency ablation.

Table 2. Lesion characteristics.

Lesion characteristics	Total (n = 58)
Location
Thyroid bed	3 (5.17)
Cervical lymph node	6 (10.34)
Lateral lymph node	49 (84.49)
Ultrasound signs
Margin
Clear	51 (87.93)
Unclear	7 (12.07)
Shape
Regular	50 (86.21)
Irregular	8 (13.79)
Cystic components
Yes	8 (13.79)
No	50 (86.21)
Echogenicity
Isoechoic	34 (58.62)
Hypoechoic	24 (41.38)
Hilum present
Yes	6 (10.34)
No	52 (89.66)
Calcification
Yes	33 (56.90)
No	25 (43.10)
Microcalcifications
Yes	27 (81.81)
No	6 (18.18)
Vascularization
Absent	28 (48.28)
Normal	26 (44.82)
Increased	4 (6.90)
Initial largest diameter^a (mm, range)	13.71 ± 6.48 (4–29)
Initial tumor volume^a (mm^3, range)	520.43 ± 627.85 (12.57–2879.79)
L/S ratio^a	2.31 ± 0.92 (1.20–5.60)
Contrast-enhanced ultrasound signs
Contrast enhancement intensity
Hyperenhancement	24 (41.38)
Isoenhancement	18 (31.03)
Hypoenhancement	7 (12.07)
Absent of enhancement	3 (5.17)
NA^b	6 (10.35)
Contrast enhancement patterns
Homogenous	5 (8.62)
Heterogenous	53 (91.38)
Contrast enhancement direction
Centripetal fill-in	5 (8.63)
Centrifugal fill-in	2 (3.35)
Mixed fill-in	44 (75.86)
NA^b	7 (12.07)

^aData are expressed as mean ± standard deviation.

^bNA: not available.

Table 3. Long-term follow-up results of RFA.

	Largest diameter^a, mm	Volume^a, mm^3	VRR^a (%)	p Value
Pre-ablation	520.43 ± 627.85	13.71 ± 6.48
1 month	337.66 ± 369.37	10.83 ± 5.06	54.17 ± 63.17	<.001
3 months	124.18 ± 164.6	6.37 ± 5.49	72.90 ± 35.69	<.001
6 months	68.45 ± 142.95	3.26 ± 4.13	82.28 ± 42.11	<.001
12 months	23.40 ± 54.04	2.13 ± 2.93	89.30 ± 30.78	<.001
24 months	12.99 ± 56.13	0.67 ± 2.31	92.57 ± 31.90	<.001
36 months	5.86 ± 23.44	0.73 ± 2.00	96.60 ± 13.35	<.001
48 months	4.97 ± 15.33	0.73 ± 1.88	96.88 ± 9.73	<.001
60 months	3.27 ± 14.64	0.45 ± 1.47	98.14 ± 8.32	<.001
Last follow-up	0.00	0.00	100.00	<.001

^aData are expressed as mean ± standard deviation.