Background: The indications for surgery in primary hyperparathyroidism (1HPT) are the same for patients with and without localization on imaging. However, patients with negative imaging may not be referred for surgery or the surgeon may be reluctant to operate. We compare outcomes in patients with negative imaging to those with localization.
Methods: A review of patients who underwent primary operation for 1HPT with a preoperative Tc99 sestamibi I-123 (MIBI) scan was conducted. Imaging, laboratory, operative findings, pathologic findings, and outcomes were used to compare patients with negative scans to those with localization.
Results: A total of 2,681 patients had an operation for 1HPT with preoperative MIBI. MIBI imaging was negative in 136 (5.7 %). The negative MIBI group had a lower calcium (10.9 vs. 11.0 mg/ml, P=0.02), phosphorus (2.9 vs. 3.1 mg/dl, P<0.001), and urinary calcium (251 vs. 287 mg/ml, P=0.02) and no difference in parathyroid hormone, 25-OH vitamin D, or bone loss. Multigland resection was higher with a negative scan (32 vs. 13 %, P<0.001). A curative operation was performed in 90.4 % with a negative MIBI compared to 97.5 % with localization (P<0.001). Patients who underwent successful surgery despite a negative MIBI scan had lower calcium (10.8 vs. 11.1 mg/ml, P=0.04) and parathyroid hormone (98 vs. 196 pg/ml, P=0.03) than those not cured. Patients with both a negative ultrasound result and negative MIBI had a cure rate of 89 %.
Conclusions: A curative operation is performed at an acceptably lower rate with negative MIBI imaging. A decision for surgery with a negative MIBI finding should consider lower cure rates and symptom severity.