A >50% Intraoperative Parathyroid Hormone Decrease Into Normal Reference Range Predicts Complete Excision of Malignancy in Patients With Parathyroid Carcinoma

• Published in: The Journal of surgical research
• Main Authors: Armstrong, Valerie L, Vaghaiwalla, Tanaz M, Saghira, Cima, Chen, Cheng-Bang, Wang, Yujie, Anantharaj, Johan, Ackin, Mehmet, Lew, John I
• Format: Journal Article
• Language: English
• Published: United States 27-12-2023
• Subjects: Intraoperative PTH monitoring; Parathyroid cancer; Parathyroid malignancy; Primary hyperparathyroidism; Parathyroid carcinoma; ioPTH monitoring
• ISSN: 1095-8673

The mainstay of successful treatment for parathyroid carcinoma remains complete surgical excision. Although intraoperative parathyroid hormone (ioPTH) monitoring is a useful adjunct during parathyroidectomy for benign primary hyperparathyroidism, its utility for parathyroid carcinoma remains unclear.
A retrospective review of 796 patients who underwent parathyroidectomy with ioPTH monitoring for primary hyperparathyroidism revealed 13 patients with parathyroid carcinoma on final pathology from two academic institutions. A systematic review yielded 5 additional parathyroid carcinoma patients. Complete excision of malignancy, or operative success (eucalcemia ≥6 mo. after parathyroidectomy); operative failure (persistent hypercalcemia <6 mo. after parathyroidectomy); and perioperative complications were evaluated. Comparison of the >50% ioPTH decrease alone to >50% ioPTH decrease into normal reference range was analyzed using Chi-squared, Kolmogorov-Smirnov, Kruskal-Wallis tests.
All 18 parathyroid carcinoma patients achieved a >50% ioPTH decrease, and 14 patients also had a final ioPTH level decrease into normal reference range. 93% of patients who met normal parathyroid hormone reference range had operative success, whereas only two of the four (50%) patients with parathyroid carcinoma with a >50% ioPTH decrease alone demonstrated operative success.
Parathyroidectomy guided by a >50% ioPTH decrease into normal reference range may better predict complete excision of malignant tissue in patients with parathyroid carcinoma compared to >50% ioPTH decrease alone. IoPTH monitoring should be used in conjunction with clinical judgment and complete en bloc resection for optimal treatment and success.