Diagnosis of parathyroid cancer

Diagnosis is the process of finding out the cause of a health problem. Diagnosing parathyroid cancer usually begins with a visit to your family doctor. Your doctor will ask you about any symptoms you have and do a physical exam. Based on this information, your doctor may refer you to a specialist or order tests to check for parathyroid cancer or other health problems.

The process of diagnosis may seem long and frustrating. It can be hard to diagnose parathyroid cancer because the symptoms can be similar to those caused by non-cancerous parathyroid tumours. It’s important for the healthcare team to rule out other reasons for a health problem before making a diagnosis of parathyroid cancer.

The following tests are usually used to rule out or diagnose parathyroid cancer. Many of the same tests used to diagnose cancer are used to find out the stage (how far the cancer has spread). Your doctor may also order other tests to check your general health and to help plan your treatment.

Your health history is a record of your symptoms, risk factors and all the medical events and problems you have had in the past. Your doctor will ask questions about your history of:

• symptoms that suggest hyperparathyroidism (overactive parathyroid glands), hypercalcemia (too much calcium in the blood) or parathyroid cancer
• inherited conditions such as multiple endocrine neoplasia (MEN), hyperparathyroidism-jaw tumour syndrome, familial isolated hyperparathyroidism
• receiving radiation therapy to the head and neck area

Your doctor may also ask about a family history of:

• parathyroid tumours and parathyroid cancer
• risk factors for parathyroid cancer
• other cancers

A physical exam allows your doctor to look for any signs of parathyroid cancer. During a physical exam, your doctor may:

• feel the neck for any lumps
• check your blood pressure

Find out more about a physical exam.

Blood chemistry tests measure certain chemicals in the blood. They show how well certain organs are functioning and can help find abnormalities. Blood chemistry tests used to diagnose hyperparathyroidism and help diagnose parathyroid cancer include the following.

Calcium levels are measured to check for too much calcium in the blood (hypercalcemia). Levels of calcium greater than 14 mg/dL can mean parathyroid cancer is present.

Parathyroid hormone (PTH) levels are measured to check for too much PTH. Very high levels of PTH (5 to 10 times higher than normal) may mean parathyroid cancer is present.

Alkaline phosphatase (ALP) and phosphorus are measured along with calcium and PTH levels. A high ALP may mean increased bone activity caused by hyperparathyroidism. A low phosphorus level can mean there is hypercalcemia caused by hyperparathyroidism.

Find out more about blood chemistry tests.

A urinalysis is a test that measures substances found in urine. It may be done to check how the kidneys are working and find out if there is too much calcium in the urine (hypercalciuria). Hypercalciuria may be caused by hyperparathyroidism.

Find out more about a urinalysis.

A parathyroid scan (also called a sestamibi scan) is a nuclear medicine imaging test that uses a radioactive substance and a special camera to take pictures of the parathyroid glands. It is mainly used to check for hyperparathyroidism and any parathyroid tumours.

The radioactive substance (called technetium-99m sestamibi) is injected into a vein in your arm and travels throughout the body. It is absorbed by any overactive parathyroid glands. After about 10 minutes, a gamma camera is used to take pictures of the neck and chest. Radioactive areas will show up brightly in the pictures. More pictures are taken a few hours later.

A parathyroid scan is often done with single photon emission computed tomography (SPECT). The camera moves around the neck to make 3-D images.

An ultrasound uses high-frequency sound waves to make images of parts of the body. It may be used to look for abnormal parathyroid glands, including parathyroid adenomas, and other abnormalities in the neck.

Find out more about an ultrasound.

A computed tomography (CT) scan uses special x-ray equipment to make 3-D and cross-sectional images of organs, tissues, bones and blood vessels inside the body. A computer turns the images into detailed pictures.

A CT scan may be used to find the location of a tumour and measure its size. It is more often used to check if parathyroid cancer has spread to other parts of the body, such as the lungs or the liver.

Find out more about a CT scan.

It is usually hard to tell the difference between parathyroid cancer and a non-cancerous parathyroid tumour (parathyroid adenoma) based on blood and imaging tests alone. Doctors usually need to do surgery to make a definite diagnosis of parathyroid cancer or parathyroid adenoma.

The surgery done is called a parathyroidectomy. It completely removes a parathyroid gland. All of the tissue removed during surgery is sent to a lab. A pathologist examines the tissues under a microscope to confirm if a parathyroid tumour is cancerous or non-cancerous.

Doctors don’t usually use a needle to remove tissue from the parathyroid glands (a biopsy) because using this method, they can’t tell the difference between parathyroid cancer and a non-cancerous parathyroid adenoma.

Magnetic resonance imaging (MRI) uses powerful magnetic forces and radiofrequency waves to make cross-sectional images of organs, tissues, bones and blood vessels. A computer turns the images into 3-D pictures.

An MRI may be used to check if parathyroid cancer has spread to other parts of the body.

Find out more about an MRI.

A bone scan uses bone-seeking radioactive materials called radiopharmaceuticals and a computer to create a picture of the bones. It is used to check if parathyroid cancer has spread to the bones (bone metastasis).

Find out more about a bone scan.

To make the decisions that are right for you, ask your healthcare team questions about a diagnosis.