[SHOULD PATIENTS WITH PRIMARY HYPERPARATHYROIDISM AND NEGATIVE IMAGING STUDIES BE REFERRED TO SURGERY?].

Introduction: Parathyroidectomy is the only curative treatment for primary hyperparathyroidism (PHPT). In cases where imaging fails to demonstrate an adenoma, a bilateral neck exploration (BNE) is performed. Negative imaging is thought to predict surgical failure, and patients with negative imaging are often not referred for surgery. These patients are at risk for disease progression.

Aims: Evaluate the effect of negative imaging on surgical findings and the cure rate in patients with PHPT.

Methods: A total of 133 patients underwent parathyroidectomy for PHPT. Data were retrospectively retrieved including preoperative imaging, surgical findings and results. A comparison was conducted between patients with negative and positive imaging. The main outcome measure was cure.

Results: A negative MIBI (methoxy-isobutyl-isonitrile) scan was seen in 30 (22%) patients and a negative US in 46 (34.5%). Patients with negative MIBI scan more commonly underwent BNE compared with patients with a positive scan (53% vs. 25%, respectively, p=0.0046). Patients with negative imaging had a significantly higher rate of multigland disease compared with patients with positive imaging (35% vs. 12%, p=0.004, for the MIBI scan; 27% vs. 12%, p=0.024, for the US, respectively). Overall cure rate was 96%. Highest cure rates were seen in patients with both positive MIBI and US (99% cure rate) and lowest cure rates of 67% in patients with triple negative imaging (MIBI scan, US and 4DCT (Dual computed tomography)) (p=0.003).

Conclusions: Localization of an adenoma in preoperative imaging predicts very high cure rates in patients with PHPT. Negative imaging increases the risk for multigland disease and is associated with lower cure rates.