Endocrine Abstracts

Introduction: Ethanol ablation (EA) of “persistent or recurrent” neck nodal metastases (NNM) in adult papillary thyroid carcinoma (APTC) patients was first introduced in 1993 to clinical endocrine oncologic practice (JCEM 2011;96: 2717). At Mayo Clinic we have been impressed by the efficacy of EA in controlling postoperative NNM in stage I APTC patients. We now describe the long-term outcome results of EA in controlling recurrent NNM in 41 patients consecutively managed in one endocrinologist’s practice during 2001-2017.

Methods: For study inclusion all 41 node-positive stage I APTC patients (mean MACIS score 4.1) were treated with bilateral thyroidectomy (BT), extensive nodal resection and radioactive iodine therapy (RIT) and were followed at Mayo Rochester with neck ultrasound (US) exams for >48 months after EA. Each received a median cumulative RIT dose of 5.55 GBq (range 1.11-20.35); pre-EA 28 patients (68%) had 41 additional neck surgeries with postoperative unilateral cord paresis (UCP) in four. The cytologic diagnosis of PTC in 71 NNM (volume range 12-1404 mm³; median 150) selected for EA was confirmed by US-guided biopsy. The techniques of EA (AJR 2002;178:699) and follow-up protocol details were as previously described (JES 2020;4:bvaa095).

Results: The 41 patients (26 women, 15 men; median age 36 yr) were followed by Mayo US for 4.1-20.6 yr; mean 10.5 yr); each had 1-4 NNM (median 1). 67/71 NNM (94%) received 2-4 (median 2) ethanol injections (total volume ranged 0.2-3.0 mL; median 0.8). Post-EA all 71 ablated NNM (46% at levels 6/7) shrank (mean volume reduction of 93%) and nodal hypervascularity was eliminated. 39 NNM (55%) with initial volumes of 12-1404 mm³ (median 164) disappeared on neck sonography.32 hypovascular foci from ablated NNM (pre-EA volume range 31-636 mm³; median 147) were identifiable with volume reductions of 13-98% observed (median 81%). There were no complications and no post-procedure hoarseness. EA was successfully performed in 3 patients with known UCP on 5 NNM (3 central; 2 lateral) situated on the side with the intact RLN function and 4 (80%) disappeared. Latest median post-EA serum thyroglobulin (range <0.1 – 1.4 ng/mL) on TSH-suppressive treatment in 39 patients was 0.2 ng/mL.

Conclusions: EA of NNM in stage I APTC is effective and safe. Our present results demonstrate that for patients with stage I APTC, who do not wish further surgery or RIT and are uncomfortable with active surveillance, EA represents a well-tolerated and minimally invasive outpatient management option for the control of recurrent NNM.