Clinical Treatment and Management

The medical management of hypercalcemia, particularly in patients with unresectable disease or without measurable disease, is critical and must be the initial treatment goal in all patients with HPT. Conventional treatment with intravenous fluids, diuretics, and antiresorptive agents such as bisphosphonates, gallium, or mithramycin may help control the hypercalcemia.[12] Calcimimetic agents that directly block secretion of the parathyroid hormone from the glands may offer an important approach to medical therapy of primary HPT associated with parathyroid cancer.[19,20]

Surgery is the only effective therapy for parathyroid carcinoma.[1,5,6] Preoperative suspicion and intraoperative recognition of parathyroid carcinoma is critical to achieve a favorable outcome, which involves en bloc resection of the tumor with all potential areas of invasion at the initial operation.[12,21,22]

One analysis of the literature indicated a local recurrence rate of 8% after an en bloc resection and 51% after a standard parathyroidectomy.[23] En bloc excision during the initial procedure for parathyroid cancer may involve resection of the recurrent laryngeal nerve because the nerve is at risk for invasion by any residual tumor and subsequent loss of function. The increased potential for long-term local control achieved by en bloc excision outweighs the complication of postoperative vocal cord paralysis, which can be improved with techniques such as Teflon injection into the paralyzed cord. Cervical lymph node dissection should be performed only for enlarged or firm nodes, particularly those found in the level VI paratracheal nodes and levels III and IV internal jugular nodes.[1]

Because of the fairly indolent biology of this cancer, the management of recurrent or metastatic disease is primarily surgical. Significant palliation may result from the resection of even very small tumor deposits in the neck, lymph nodes, lungs, or liver.[2,13,16,24,25] Accessible distant metastases should be resected when possible.[5] Localization studies performed before the first operation or reoperation may include technetium Tc 99m-sestamibi (MIBI) scan, single photon emission computed tomography, computed tomography (CT)-MIBI image fusion, ultrasound, CT, selective angiogram, and selective venous sampling for PTH.[3] CT and magnetic resonance imaging are useful imaging adjuncts for the localization of distant metastases.[5,26]

Nonsurgical forms of therapy for parathyroid carcinoma generally have poor results.[1,5,6,11] Some investigators have advocated the use of adjuvant radiation therapy to decrease the local recurrence rate.[27,28] Patients with this disease should be monitored for life because they may be at a relatively high risk of multiple relapses over prolonged periods of time.[11] Patients rarely die of the tumor itself; rather, they die of the metabolic complications of uncontrolled HPT.