MON-757 Percutaneous Ethanol Ablation (PEA) Of Parathyroid Adenomas: A Single-Center Outcomes Study

Abstract Disclosure: J.R. Hewlett: None. J.G. Sfeir: None. R.A. Wermers: None. J.J. Schmitz: None. Percutaneous ethanol ablation (PEA) is a non-surgical technique used in the management of hyperparathyroidism (HPT) since the 1980s. Previously published cohorts are small and/or focused on patients with primary hyperparathyroidism (PHPT) in the setting of multiple endocrine neoplasia type 1 (MEN1). New randomized controlled trial data suggests similar response rates between parathyroidectomy and PEA (98.5% vs 91.1%) for uniglandular disease, and a previously published cohort of PEA in patients with MEN1 and recurrent multiglandular PHPT at our institution reported post-PEA normocalcemia in 74.5% of patients. This retrospective cohort study examined the treatment response to PEA in those with PHPT (including MEN1) and tertiary HPT (THPT) at a single institution between 1997-2023. Those with secondary hyperparathyroidism or eucalcemic PHPT were excluded. The primary outcome was a serum calcium ≤10.1 mg/dL at 3-6 months and secondary outcomes included number and volume of ethanol injections, time to recurrence of HPT, and complications of PEA. A total of 83 patients were included. Most were women (62.7%) and the median age at diagnosis of HPT was 40 years. The majority had PHPT (90.4%), and many (86.7%) had previously undergone surgery. The most common indications for PEA were risk for hypoparathyroidism with additional surgery (72.3%) poor surgical candidacy (16.9%), and patient preference (8.4%). The mean calcium was 10.7 mg/dL (95% CI 10.56-10.85) and the mean PTH was 164 pg/mL (95% CI 120.6-208.3) prior to PEA. The mean number of ethanol injections was 3.0 (95% CI 2.6 – 3.4) and the cumulative volume of ethanol was 1.2 mL (95% CI 1.0-1.4). At 3-6 months, 68.3% of treated patients had calcium ≤10.1 mg/dL with a mean value of 9.4 mg/dL (95% CI 9.1-9.6). Of those, 42% did not have recurrence at most recent follow-up. Of those with recurrence, a post-PEA calcium ≤10.1 mg/dL at 3-6 months was associated with a longer time to recurrence than those without (36.9 months versus 3.75 months; P=0.0009). There was no significant difference between the number of times (P=0.56) or the volume (P=0.41) of ethanol injected between those with calcium of ≤10.1 mg/dL at 3-6 months and those without. Hypocalcemia was observed in 8 (9.6%; transient in 75%), hypoparathyroidism in 3 (3.6%; transient in 66.7%), laryngeal nerve injury in 2 (2.4%; transient in 50%), and hoarseness in 9 (10.8%; transient in 100%) patients. This is the largest North American cohort of patients who received PEA for HPT and represents a broader review of HPT than previously published. Our rate of post-PEA eucalcemia is lower than previously reported, however this cohort was complex with a high proportion of multiglandular disease (80.7%), MEN1 (39.8%) and prior surgeries (mean 1.7 per person; 95% CI 1.5-1.9). PEA remains a safe and effective treatment for patients with recurrent HPT, especially those at high risk of post-surgical hypoparathyroidism. Presentation: Monday, July 14, 2025