Radiofrequency ablation of primary thyroid carcinoma: efficacy according to the types of thyroid carcinoma

Figures & data

Table 1. Demographic and clinical characteristics before radiofrequency ablation (RFA) of primary thyroid cancer.

								TNM stage
Patient no.	Sex	Age (y)	Pathology	Reason for RFA	Location	Diameter (cm)	Volume (ml)	T	N	M
1	F	83	Anaplastic carcinoma	Non-operable, conservative care	Left lobe	5	52.3	4a	1b	1 (lung)
2	F	80	Anaplastic carcinoma	Non-operable, conservative care	Left lobe	8.7	163.41	4b	1b	1 (lung, bone, distant lymph nodes)
3	F	83	Papillary carcinoma	Old age Refused surgery	Right mid pole	0.64	0.097	1a	0	0
4	F	77	Papillary carcinoma	Old age Refused surgery	Left lobe	8	126.88	3	0	0
5	M	54	Papillary carcinoma	Previous history of right lobectomy due to PTC	Left mid pole	0.5	0.044	1a	0	0
6	F	49	Papillary carcinoma	Refused surgery	Left lower pole	0.74	0.185	1a	0	0
7	M	58	Papillary carcinoma	Comorbidities	Right mid pole	0.9	0.3	1a	0	0
8	M	58	Papillary carcinoma	Comorbidities	Left lower pole	0.81	0.151	1a	0	0
9	F	36	Papillary carcinoma	Refused surgery	Right mid pole	0.8	0.183	1a	0	0

Figure 1. Radiofrequency ablation (RFA) of anaplastic thyroid carcinoma (A) Initial computed tomography (CT) image of an 80-year-old woman revealed 8 cm mass in the left thyroid gland with neck bulging and trachea deviation, proven as anaplastic thyroid carcinoma on core-needle biopsy. (B) Follow-up CT after first RFA (two days after initial RFA) revealed a 8.5 cm ablation zone with decreased enhanced portion of the mass. (C) Follow-up CT after second RFA (five days after initial RFA) revealed a 8.5 cm ablation zone. (D) On last follow-up CT after third RFA (39 days after initial RFA), CT revealed a 10 cm mass in the thyroid gland with unchanged neck bulging and trachea deviation.

Figure 2. Gradual reduction of papillary thyroid macrocarcinoma after two sessions of RFA (A) Initial ultrasonography (US) of a 77-year-old woman revealed 8.0 cm predominantly cystic mass in the left thyroid gland. (B) After first RFA, US revealed a smaller but persistent, 2.4 cm ill-defined ablation zone in the left thyroid gland. (C) After second RFA, US revealed a smaller, 1.9 cm ill-defined ablation zone in the left thyroid gland. (D) At 12-months follow-up after two sessions of RFA, US revealed a smaller, 1.7 cm ill-defined ablation zone in the left thyroid gland. (E) At 18-months follow-up, US revealed a smaller with decreased calcification, 1.4 cm ill-defined ablation zone in the left thyroid gland.

Figure 3. Gradual reduction and complete disappearance of papillary thyroid microcarcinoma after one session of radiofrequency ablation. (A) Initial US of a 49-year-old woman revealed a 0.8 cm mass in the left thyroid gland proven as papillary thyroid carcinoma on CNB. (B) At one-year follow-up after one session of RFA, US revealed a smaller, 0.4-cm ill-defined ablation zone in the left thyroid gland. (C) At 24-months follow-up after RFA, US revealed complete disappearance of ablation zone with subtle scar in the left thyroid.

Table 2. Outcome of radiofrequency ablation with primary thyroid cancer^a.

	Group 1 (n = 2)		Group 2 (n = 1)		Group 3 (n = 6)
Measurement	Initial	After RFA	Initial	After RFA	Initial	After RFA
Largest diameter (cm)	6.9 ± 2.6	−	8	1.4	0.73 ± 0.13	0.40 ± 0.48
Volume (mL)	107.9 ± 78.6	−	126.9	0.7	0.16 ± 0.08	0.07 ± 0.12
Volume reduction ratio	−		99.4%.		47.8%.
Symptom or cosmetic problems	No change		Much improved		−

^a Mean follow-up months: 19.3 months (range, 17–24 months).

Table 3. Treatment parameters of primary thyroid cancer.

	Group 1^a (n =2)	Group 2^b (n = 1)	Group 3^c (n = 6)
Mean ablation time (s)	1120 ± 396	720	300 ± 127
Mean RF power (Watt)	128 ± 4	30	16 ± 5
Active tip (mm)	10 mm, 15 mm	5 mm	5 mm, 7 mm
Total energy (Joule)	147700 ± 60387	21600	5675 ± 3473
Energy/mL (J/mL)	1586.4 ± 595.7	170.2	40183.6 ± 19774.9
Mean treatment session	2.5	2	1

^a Anaplastic thyroid carcinoma.

^b Macro papillary thyroid carcinoma.

^c Micro papillary thyroid carcinoma.