Efficacy and safety of percutaneous ultrasound guided radiofrequency ablation for treating cervical metastatic lymph nodes from papillary thyroid carcinoma

Abstract

Purpose: The aim of this study was to assess the effectiveness and safety of ultrasound guided percutaneous radiofrequency ablation (RFA) of cervical metastatic lymph nodes (LNs) from papillary thyroid carcinoma.

Methods: 54 metastatic LNs confirmed by percutaneous biopsy in 33 patients with previous total thyroidectomy and radioiodine therapy were enrolled in this retrospective study. US and contrast-enhanced ultrasound (CEUS) examinations were performed before ablation. Follow-up consisted of conventional US, CEUS, thyroglobulin (Tg) level at 1, 3, 6, and 12 months and every 6 months thereafter. In 3 months after ablation, US-guided core needle biopsy (CNB) was performed in the center, at the edge of the ablation area to exclude recurrence.

Results: Technical success was obtained in all 54 lymph nodes (100%) without immediate or later major complications occurred. With a mean follow-up of 21 ± 4 months (range 12-24 months), there were no evidence of recurrence at ablated sites. After RFA, 33 metastatic LNs completely disappeared (33/54, 61.1%) and 21 metastatic lymph nodes remained as small scarlike lesions (21/54, 38.9%) at the last follow-up visit. The mean volume reduction ratio (VRR) was 32.7 ± 8.6% (range 21.2-59.3%), 46.8 ± 9.7% (range 33.6-68.1%), 62.5 ± 12.1% (range 42.5-95.4%), 77.1 ± 10.6% (range 54.3-100.0%), 89.2 ± 8.3% (range 68.7-100.0%) and 94.9 ± 5.3% (range 78.2-100.0%) at 1, 3, 6, 12, 18 and 24 months after RFA respectively. Significant differences in the VRR were found between every two follow-up visits (P < 0.001). At the last follow-up visit, the mean serum Tg level decreased from 10.2 ± 5.1 ng/ml (range 0.8-16.2 ng/ml) to 1.1 ± 0.8 ng/ml (range 0.2-3.1 ng/ml) (P < 0.001).

Conclusions: Ultrasound guided percutaneous RFA for cervical metastatic LNs from papillary thyroid carcinoma is a feasible, effective and safe therapy. This procedure shows a nonsurgical therapeutic option that can eradicate the lesions with a very low complication rate.

Keywords: Metastatic lymph node; Papillary thyroid carcinoma; Radiofrequency ablation (RFA); Ultrasound.

Fig. 1

Images of RFA treatment of a metastatic LN at left cervical level III in a 58-year-old woman previously underwent total thyroidectomy, two subsequent neck dissection and one subsequent ¹³¹I ablation for papillary thyroid carcinoma. a Conventional ultrasound image shows a hypoechoic LN with no lymphatic hilus (white arrows). b CEUS shows an irregular enhancement (white arrows) in the metastatic LN with unenhancement foci (arrowheads). c During RFA, ultrasound monitoring of the procedure shows gas formation in the metastatic LN which covered by a hyperechoic ablation area (white arrows). d CEUS performed immediately after RFA shows a complete lack of enhancement in the treated area (white arrows). e One month after RFA, CEUS shows the treated area shrunk and that complete lack of enhancement (white arrows). f Six month after RFA, CEUS shows complete lack of enhancement in the treated area, remained as a small scarlike lesion (white arrows)

Fig. 2

Changes in Volume Reduction Ratio at Each Follow-up