Parathyroid Parathyroid Cancer

Definition

Parathyroid carcinoma is a rare disorder accounting for fewer than 1% of primary hyperparathyroidism cases. Parathyroid carcinoma is more often discovered during reoperative procedures for recurrent or persistent hypercalcemia and may occur in both sporadic and familial forms. Progress in molecular biology and cancer therapeutics are an active area of interest at Columbia University and the opportunity for clinical trial participation testing the best available therapeutics for this form of cancer are available to eligible patients (see Research).

Symptoms

Patients with parathyroid cancer are typically diagnosed with sporadic primary hyperparathyroidism and have the same symptoms and manifestations of elevated high calcium levels described in hyperparathyroid patients. Suspicion of a malignant process is signaled by any one or more of the of the following symptoms:

Significantly elevated calcium levels (= 14 mg/dl)
Severe bone disease
Severe kidney disease, multiple stones
Hard lymph nodes or lump in the neck
Difficulty swallowing
Difficulty breathing
Hoarseness

Diagnosis

A diagnosis of parathyroid cancer may be suspected at the time of initial surgical procedure for hyperparathyroidism when a hard mass is found with invasion into surrounding structures (usually the thyroid gland) and fibrosis, or suspicious lymph nodes that contain disease. Often times a diagnosis of cancer is ascertained after the surgical removal of what was thought to be a benign adenoma following careful histopathologic evaluation of the surgical specimen. Because the histopathologic features of parathyroid carcinoma and adenoma may overlap a definitive diagnosis of cancer requires the presence of invasion of surrounding structures, metastatic regional (lymph nodes) or distant disease (usually lung and bones).

Treatment Options

Surgery: Surgery remains the only effective treatment for parathyroid cancer. Complete en bloc resection of all disease in the neck including the lymph glands and portion of the thyroid gland offers the best chance for cure. Up to 25% of patients will have regional disease in the neck at the time of initial operation and many will develop recurrent disease in the neck with or without aggressive initial surgery. Once parathyroid cancer has traveled beyond the neck area, surgery is no longer a treatment option.
External beam radiation therapy: Is sometimes used for treatment of residual disease that cannot be surgically removed or as an adjuvant therapy following complete surgical resection. Because parathyroid cancer is such a rare disorder, we are not certain of the added value of this treatment to surgical resection.
Medical therapy: Patients who develop distant disease can have functional metastases causing PTH oversecretion and elevated blood calcium levels. Chemotherapy is not effective in treating disease that has spread. Experimental "anti-calcium" medications called calcimimetics are presently being tested in experimental clinical trials and have shown some utility at controlling calcium levels, however long-term results are not available. (see Research) Outside of a clinical experimental trial, patients are supported by available medical therapy to try to avoid complications of persistently high serum calcium.