Parathyroid cancer is extremely rare and occurs in only 1 out of every 2 million people. Patients with parathyroid cancer usually have very high PTH levels (usually more than 5 times the upper limit of normal values) and very high calcium levels (often higher than 13 to 14 mg/dL). In addition, unlike most cases of parathyroid disease where the hyperactive parathyroid glands cannot be felt, patients with parathyroid cancer may have a very hard lump in the neck. By the time the parathyroid cancer has been found, it has usually grown into surrounding structures like the muscle and thyroid lobe. The best chance of curing parathyroid cancer is to surgically remove the cancer, thyroid lobe, and any structures the cancer has grown (i.e. invaded) into. After the operation, the patient must be followed closely with blood tests and imaging tests like an ultrasound or PET scan at regularly scheduled times to look for recurrence (i.e. cancer that grows back). If there is a recurrence, most patients will have another operation to remove as much of the cancer as possible. Patients may also be started on a medication called Cinacalcet (Sensipar), which tricks the body into lowering the blood calcium levels. Chemotherapy and radiation therapy do not work well against parathyroid cancer.