Summary

Key Points

• Parathyroid cancer is a rare disease in which malignant (cancer) cells form in the tissues of a parathyroid gland.
• Having certain inherited disorders can increase the risk of developing parathyroid cancer.
• Signs and symptoms of parathyroid cancer include weakness, feeling tired, and a lump in the neck.
• Tests that examine the neck and blood are used to detect (find) and diagnose parathyroid cancer.
• Certain factors affect prognosis (chance of recovery) and treatment options.

Parathyroid cancer is a rare disease in which malignant (cancer) cells form in the tissues of a parathyroid gland.

The parathyroid glands are four pea-sized organs found in the neck near the thyroid gland. The parathyroid glands make parathyroid hormone (PTH or parathormone). PTH helps the body use and store calcium to keep the calcium in the blood at normal levels.

A parathyroid gland may become overactive and make too much PTH, a condition called hyperparathyroidism. Hyperparathyroidism can occur when a benign tumor (noncancer), called an adenoma, forms on one of the parathyroid glands, and causes it to grow and become overactive. Sometimes hyperparathyroidism can be caused by parathyroid cancer, but this is very rare.

The extra PTH causes:

• The calcium stored in the bones to move into the blood.
• The intestines to absorb more calcium from the food we eat.

This condition is called hypercalcemia (too much calcium in the blood).

The hypercalcemia caused by hyperparathyroidism is more serious and life-threatening than parathyroid cancer itself and treating hypercalcemia is as important as treating the cancer.

Risk Factors

Having certain inherited disorders can increase the risk of developing parathyroid cancer.

Anything that increases the chance of getting a disease is called a risk factor. Risk factors for parathyroid cancer include the following rare disorders that are inherited (passed down from parent to child):

• Familial isolated hyperparathyroidism (FIHP).
• Multiple endocrine neoplasia type 1 (MEN1) syndrome.

Treatment with radiation therapy may increase the risk of developing a parathyroid adenoma.

Screening and Detection

Tests that examine the neck and blood are used to detect (find) and diagnose parathyroid cancer.

Once blood tests are done and hyperparathyroidism is diagnosed, imaging tests may be done to help find which of the parathyroid glands is overactive. Sometimes the parathyroid glands are hard to find and imaging tests are done to find exactly where they are.

Parathyroid cancer may be hard to diagnose because the cells of a benign parathyroid adenoma and a malignant parathyroid cancer look alike. The patient’s symptoms, blood levels of calcium and parathyroid hormone, and characteristics of the tumor are also used to make a diagnosis.

The following tests and procedures may be used:

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
• Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease. To diagnose parathyroid cancer, the sample of blood is checked for its calcium level.
• Parathyroid hormone test: A procedure in which a blood sample is checked to measure the amount of parathyroid hormone released into the blood by the parathyroid glands. A higher than normal amount of parathyroid hormone can be a sign of disease.
• Sestamibi scan: A type of radionuclide scan used to find an overactive parathyroid gland. A very small amount of a radioactive substance called technetium 99 is injected into a vein and travels through the bloodstream to the parathyroid gland. The radioactive substance will collect in the overactive gland and show up brightly on a special camera that detects radioactivity.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• SPECT scan (single photon emission computed tomography scan): A procedure that uses a special camera linked to a computer to make a 3-dimensional (3-D) picture. A very small amount of a radioactive substance is injected into a vein. As the substance travels through the blood, the camera rotates around the neck and takes pictures. Blood flow and metabolism are higher than normal in areas where cancer cells are growing. These areas will show up brighter in the picture. This procedure may be done just before or after a CT scan.
• Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram.
• Angiogram: A procedure to look at blood vessels and the flow of blood. A contrast dye is injected into the blood vessel. As the contrast dye moves through the blood vessel, x-rays are taken to see if there are any blockages.
• Venous sampling: A procedure in which a sample of blood is taken from specific veins and checked to measure the amounts of certain substances released into the blood by nearby organs and tissues. If imaging tests do not show which parathyroid gland is overactive, blood samples may be taken from veins near each parathyroid gland to find which one is making too much PTH.

Signs and Symptoms

Signs and symptoms of parathyroid cancer include weakness, feeling tired, and a lump in the neck.

Most parathyroid cancer signs and symptoms are caused by the hypercalcemia that develops. Signs and symptoms of hypercalcemia include the following:

• Weakness.
• Feeling very tired.
• Nausea and vomiting.
• Loss of appetite.
• Weight loss for no known reason.
• Being much more thirsty than usual.
• Urinating much more than usual.
• Constipation.
• Trouble thinking clearly.

Other signs and symptoms of parathyroid cancer include the following:

• Pain in the abdomen, side, or back that doesn’t go away.
• Pain in the bones.
• A broken bone.
• A lump in the neck.
• Change in voice such as hoarseness.
• Trouble swallowing.

Other conditions may cause the same signs and symptoms as parathyroid cancer. Check with your doctor if you have any of these problems.

Treatment Options

There are different types of treatment for patients with parathyroid cancer.

Different types of treatment are available for patients with parathyroid cancer. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Treatment includes control of hypercalcemia (too much calcium in the blood) in patients who have an overactive parathyroid gland.

In order to reduce the amount of parathyroid hormone that is being made and control the level of calcium in the blood, as much of the tumor as possible is removed in surgery. For patients who cannot have surgery, medication may be used.

Four types of standard treatment are used:

Surgery

Surgery (removing the cancer in an operation) is the most common treatment for parathyroid cancer that is in the parathyroid glands or has spread to other parts of the body. Because parathyroid cancer grows very slowly, cancer that has spread to other parts of the body may be removed by surgery in order to cure the patient or control the effects of the disease for a long time. Before surgery, treatment is given to control hypercalcemia.

The following surgical procedures may be used:

• En bloc resection: Surgery to remove the entire parathyroid gland and the capsule around it. Sometimes lymph nodes, half of the thyroid gland on the same side of the body as the cancer, and muscles, tissues, and a nerve in the neck are also removed.
• Tumor debulking: A surgical procedure in which as much of the tumor as possible is removed. Some tumors cannot be completely removed.
• Metastasectomy: Surgery to remove any cancer that has spread to distant organs such as the lung.

Surgery for parathyroid cancer sometimes damages nerves of the vocal cords. There are treatments to help with speech problems caused by this nerve damage.

Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or stop them from growing. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal rad iation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.

Supportive care

Supportive care is given to lessen the problems caused by the disease or its treatment. Supportive care for hypercalcemia caused by parathyroid cancer may include the following:

• Intravenous (IV) fluids.
• Drugs that increase how much urine the body makes.
• Drugs that stop the body from absorbing calcium from the food we eat.

Drugs that stop the parathyroid gland from making parathyroid hormone.

New types of treatment are being tested in clinical trials.

Information about clinical trials is available from the NCI Web site.

Patients may want to think about taking part in a clinical trial.

For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.

Many of today’s standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.

Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.

Patients can enter clinical trials before, during, or after starting their cancer treatment.

Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.

Clinical trials are taking place in many parts of the country. See the Treatment Options section that follows for links to current treatment clinical trials. These have been retrieved from NCI’s listing of clinical trials.

Follow-up tests may be needed.

Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests.

Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.

Parathyroid cancer often recurs. Patients should have regular check-ups for the rest of their lives, to find and treat recurrences early.