Salivary gland cancer is a rare disease in which malignant (cancer) cells form in the tissues of the salivary glands.

The salivary glands make saliva and release it into the mouth. Saliva has enzymes that help digest food and antibodies that help protect against infections of the mouth and throat. There are 3 pairs of major salivary glands:

• Parotid glands: These are the largest salivary glands and are found in front of and just below each ear. Most major salivary gland tumors begin in this gland.
• Sublingual glands: These glands are found under the tongue in the floor of the mouth.
• Submandibular glands: These glands are found below the jawbone.

There are also hundreds of small (minor) salivary glands lining parts of the mouth, nose, and larynx that can be seen only with a microscope. Most small salivary gland tumors begin in the palate (roof of the mouth).

More than half of all salivary gland tumors are benign (not cancerous) and do not spread to other tissues.

Salivary gland cancer is a type of head and neck cancer.

Being exposed to certain types of radiation may increase the risk of salivary cancer.

Anything that increases the chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Although the cause of most salivary gland cancers is not known, risk factors include the following:

• Older age.
• Treatment with radiation therapy to the head and neck.
• Being exposed to certain substances at work.

Possible signs of salivary gland cancer include a lump or trouble swallowing.

Salivary gland cancer may not cause any symptoms. It is sometimes found during a regular dental check-up or physical exam. Symptoms caused by salivary gland cancer also may be caused by other conditions. A doctor should be consulted if any of the following problems occur:

• A lump (usually painless) in the area of the ear, cheek, jaw, lip, or inside the mouth.
• Fluid draining from the ear.
• Trouble swallowing or opening the mouth widely.
• Numbness or weakness in the face.
• Pain in the face that does not go away.

Tests that examine the head, neck, and the inside of the mouth are used to detect (find) and diagnose salivary gland cancer.

The following procedures may be used:

• Physical exam and history: An exam of the body to check general signs of health. The head, neck, mouth, and throat will be checked 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.
• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
• 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.
• PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
• 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. The picture can be printed to be looked at later.
• Endoscopy: A procedure to look at organs and tissues inside the body to check for abnormal areas. For salivary gland cancer, an endoscope is inserted into the mouth to look at the mouth, throat, and larynx. An endoscope is a thin, tube-like instrument with a light and a lens for viewing.
• Fine needle aspiration (FNA) biopsy: The removal of tissue or fluid using a thin needle. A pathologist views the tissue or fluid under a microscope to look for cancer cells.

Because salivary gland cancer can be hard to diagnose, patients should ask to have biopsy samples checked by a pathologist who has experience in diagnosing salivary gland cancer.

Certain factors affect treatment options and prognosis (chance of recovery).

The treatment options and prognosis (chance of recovery) depend on the following:

• The stage of the cancer (especially the size of the tumor).
• The type of salivary gland the cancer is in.
• The type of cancer cells (how they look under a microscope).
• The patient's age and general health.