PSAT280 Role of Radiofrequency Ablation Therapy in Recurrent Papillary Thyroid Carcinoma - A Case Study
Authors: Kennedy Randol , Morocco Michael 
Published: November 2022

Abstract

Introduction
Radiofrequency ablation (RFA) has been studied in solitary and reoccurring/ persistent papillary thyroid cancer (PTC) with favorable results. This case describes a patient with reoccurring PTC who underwent radiofrequency ablation.

Clinical Case
This is a case of a 68 year old male who was underwent an elective thyroid surgery for compressive multinodular goiter and left inferior parathyroid adenoma. Prior to his surgery he had fine needle aspiration cytologies of multiple nodules that were negative for thyroid cancer. A total thyroidectomy with excision of central cervical lymph nodes, excision of a suspicious right perithyroidal mass and a left inferior parathyroidectomy were performed. The pathology diagnosis was multifocal bilateral papillary thyroid cancer – classical type – with infiltration into perithyroidal adipose tissue and lymph node metastasis (pathological stage: mpT1b pN1a). Serum thyroglobulin was 4.9 ng/mL (reference range 1.6–59.9 ng/mL). Postoperatively, he was given adjuvant radioactive iodine (I-131 120mCi) treatment and suppressive levothyroxine at 250 µg daily, with pretreatment TSH at 14.730 µU/mL and TSH after 4 months of treatment 0.140 µU/mL. Single photon emission computed tomography (SPECT) whole body imaging done seven days post radioactive iodine therapy showed no evidence of distant metastases.
Four months after I-131 therapy, a diagnostic ultrasound for a palpable node revealed this to be a right level IIb cystic cervical lymph node (18×16×18 mm) with no overt vascularity. Serum thyroglobulin was &lt;0.2 ng/mL and thyroglobulin antibodies were &lt;14.4 IU/mL. FNA biopsy, with cytology showing papillary thyroid cancer. Needle washout thyroglobulin was elevated (1015.3 ng/mL, reference range &lt; 10ng/mL). This metastatic lymph node was concluded to be recurrent papillary cancer. Surgical dissection and percutaneous alternatives were discussed with the patient. Shared decision making between surgery, intervention radiology and the patient concluded that a less invasive procedure was preferred and the solitary node was a candidate for percutaneous ablation.
Post ablation surveillance ultrasonography showed an 80% volume reduction (11×8×12 mm) in node size six weeks post intervention and a 95% volume reduction at six months (8×5×7 mm), with decreased cystic appearance and no vascularity. No complications were reported after the procedure.

Conclusion
Current guidelines recommend that the mainstay of recurrent thyroid cancer is surgery, followed by radioactive iodine therapy and suppressive thyroid hormone replacement treatment, external beam radiotherapy and/ or chemotherapy. However within recent years, image guided ablation techniques such as radiofrequency ablation has been explored and has become an alternative in selective who wish to avoid extensive lymph node dissection. Multiple studies unanimously report a node volume reduction rate (VRR) of greater than 50%, with some studies reporting almost 99% VRR within 12-24 months; suggesting a role for RFA to replace 'berry picking surgery' in selected patients.
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