Tests for salivary gland cancer

You will have tests to check for salivary gland cancer. You might not need all of these tests. It will depend on your individual situation.

Tests your GP might do

Most people start by seeing their GP. They can do some tests to help them decide whether you need a referral to a specialist. Your GP might do:

• a physical examination, feeling around your jaw and neck
• blood tests
• arrange a chest x-ray

Tests your specialist might do

Depending on the results of your tests, your GP might refer you to a head and neck specialist.

Your specialist usually does more tests. This might include:

• neck ultrasound
• fine needle aspiration
• biopsy
• CT scan
• PET scan
• MRI scan
• testing for gene and protein changes
• testing for hormone receptors

Neck ultrasound

You have this scan to look at your neck and salivary glands.

Ultrasound scans use high frequency sound waves to create a picture of a part of the body. The ultrasound scanner has a microphone that gives off sound waves. The sound waves bounce off the organs inside your body, and are picked up again by the microphone. The microphone links to a computer. This turns the sound waves into a picture.

The sonographer puts a cold lubricating gel over the area. Then they put the ultrasound probe against your skin. You might feel a little pressure when the sonographer moves the probe over your neck. Tell them if it is uncomfortable. It shouldn’t hurt.

An ultrasound can take up to 45 minutes. The sonographer might ask you to move position a few times, so they can get the clearest pictures. 

You might have the ultrasound at the same time as having a fine needle aspiration (FNA).

Fine needle aspiration

A fine needle aspiration (FNA) is a way of taking a sample of cells from the lump or swelling. Your doctor uses a fine needle and syringe to take the cells. The samples can then be examined under a microscope.

If the lump is deeper or hard to feel, your doctor uses an ultrasound scan or CT scan to guide the needle into the right place.

You can have a local anaesthetic injection before the needle aspiration.

Biopsy

A biopsy is when the specialist takes a sample of tissue from the affected area. A pathologist looks at the tissue under a microscope to see if there are any cancer cells.

It is not a common test for salivary gland cancer. You might have it if your doctor thinks you have cancer of the minor salivary glands.

There are two main ways your doctor can look at your mouth and airways or take the biopsy sample.

Open biopsy 

An open biopsy is also called an incisional biopsy. It means cutting out a small piece of tissue from the affected area. Your doctor injects some local anaesthetic into the area to numb it. Then your doctor takes out the small sample of tissue.

This is uncomfortable but only lasts a short time.

Panendoscopy

A panendoscope is a series of connected tubes that a head and neck surgeon uses to look at your upper airways. There is a camera and light at one end, and an eyepiece at the other. Your specialist can use it to remove a sample of the affected tissue.

You have this test while you are under general anaesthetic. The doctor gently puts the endoscope up your nose and down into your throat. They will look at your:

• pharynx (throat)
• larynx (voice box)
• oesophagus (food pipe)
• trachea (windpipe)
• bronchi (breathing tubes)

Talk to your doctor before the test if you are taking medicines to thin the blood (anticoagulants).

You might have a panendoscopy if you have an abnormal area that is difficult for your doctors to access.

CT scan

CT (or CAT) scan stands for computed (axial) tomography. It is a test that uses x-rays and a computer to create detailed pictures of the inside of your body.

You might have a CT scan of your head and neck to see:

• how big the cancer is and if there are any changes to the lymph nodes in your neck
• whether the cancer has spread

PET scan

Not everyone has a PET scan when being diagnosed with salivary gland cancer. It might help your doctors see how big the cancer is and whether it has spread.

You might have a PET scan and a CT scan at the same time. This is called a PET-CT scan.

The PET scan uses a mildly radioactive drug to show up areas of your body where cells are more active than normal.

MRI scan

MRI stands for magnetic resonance imaging. It uses magnetism and radio waves to take pictures of the inside of the body.

You might have an MRI scan to see how big the salivary gland cancer is and whether it has spread.

Testing for gene and protein changes in salivary gland cancer

Some salivary gland cancers have changes (mutations) in certain genes and proteins. Your doctor can look to see if there are gene changes found on chromosomes within your cells.

Genes are found on chromosomes within all cells. They tell the cell which proteins to make.

Scientists can look at salivary gland cancer samples (biopsies) in the laboratory and search for gene changes (mutations) that change how the cancer grows. Knowing this can help your doctor:

• understand the type of salivary gland cancer you have
• make decisions about your treatment

Gene mutations

Some of the changes in genes that make the salivary gland cancer grow and divide include:

• NTRK (neurotrophic tyrosine receptor kinase) gene
• HER2

Protein changes

Some salivary gland cancers make too much of a protein called HER2 (human epidermal growth factor 2 receptor). They are called HER2 positive cancers. Certain targeted cancer drugs can target the HER2 protein.

Some salivary gland cancers have a higher than normal amount of:

• PD-1 protein (programmed cell death protein)
• PD-L1 protein

PD-1 proteins are found on a type of immune cell called T cells. PD-L1 proteins are also found on normal cells. Having higher levels of these proteins might mean you can have a type of immunotherapy treatment called a checkpoint inhibitor.

You might have immunotherapy as part of a clinical trial. It is not a standard treatment for salivary gland cancer.

Hormone receptor tests

Some salivary gland cancers make a protein called an androgen receptor. Hormones in the body can attach to these receptors and can encourage cancer cells to divide and grow. A type of hormone treatment can attach to these receptors and stop the cancer from growing. 

Your salivary gland cancer cells can be tested in the laboratory to see if it has androgen receptors. This type of hormone treatment is used for advanced or metastatic salivary gland cancer. 

Treatment

The tests you have helps your doctor find out if you have salivary gland cancer and how far it has grown. This is the stage of the cancer.

This is important because doctors recommend your treatment according to the stage of the cancer.