According to study results published in Clinical Endocrinology, intraoperative parathyroid hormone (PTH) monitoring better predicts cure for primary hyperparathyroidism in parathyroidectomy than ultrasound and methoxy iso butyl isonitrile (MIBI) scans.
Currently, there is an overreliance on preoperative imaging in the parathyroid surgical pathway. To compare the ability of intraoperative PTH monitoring to predict a cure after parathyroidectomy with the use of imaging modalities (ultrasound and MIBI scans) to preoperatively identify abnormal parathyroid glands, researchers conducted a retrospective study of 617 patients (median age, 59 years) who had undergone parathyroid surgery.
Ultrasound and MIBI scans were measured for sensitivity, specificity, accuracy, and other factors and cases of intraoperative PTH monitoring were assessed for added value, defined as the percentage of patients in whom the monitoring significantly influenced the course of operation or contributed to achieving a cure. A cure was defined as albumin-adjusted calcium ≤2.6 mmol/L during follow-up.
A total of 603 included patients were successfully cured (97.7%). Intraoperative PTH monitoring was found to have a sensitivity rate of 98.6% (P <.05) compared with 78.2% for ultrasound and 70% for MIBI (P <.05). In a similar fashion, intraoperative PTH monitoring had a sensitivity of 98.8% in detecting single-gland disease and 96.7% for multigland disease, while ultrasound and MIBI were less sensitive for both (85% vs 55% and 77.5% vs 45.5% for single- vs multigland disease, respectively; P <.05 for all).
In 41 cases in which ultrasound provided inaccurate predictions, MIBI correctly diagnosed 12 patients (29.3%) while intraoperative PTH monitoring accurately predicted cure in 41 (97.6%).
Furthermore, intraoperative PTH monitoring offered significant added value in the whole cohort (14%), as well as in patient subgroups with concordant vs discordant scans, minimally invasive vs conventional surgery, and initial vs reoperative surgery (P <.05).
The researchers noted a lack of a control group as one limitation of their study.
Summarizing their results, the researchers said, “The potential of [intraoperative PTH monitoring] to disrupt the current concept of ‘concordant scans’ and replace it with a new stepwise paradigm of ‘single positive scan’ should be further evaluated in prospective studies… Patients will be the main beneficiaries as they will have fewer scans, less radiation, and shorter waiting times for surgery.”
Shawky M, Aziz TA, Morley S, et al. Impact of intraoperative parathyroid hormone monitoring on the management of patients with primary hyperparathyroidism. Clin Endocrinol. 2018;1-8.