This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Salivary gland cancer is a rare disease in which cancerous 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 to digest food and antibodies that help protect against infections of the mouth and throat. There are 3 pairs of major salivary glands: the parotid glands, the sublingual glands, and the submandibular glands. The National Cancer Institute provides a picture of the anatomy of the salivary glands.
Some risk factors for salivary gland cancer are older age, exposure to radiation of the head and/or neck area, and family history. Signs and symptoms of the disease may include: a lump near the ear, cheek, jaw, lip, or inside of the mouth; trouble swallowing; fluid draining from the ear; numbness or weakness in the face; and on-going pain in the face.
Different types of treatment are available for patients with salivary gland cancer. Some treatments are standard (currently used by physicians) and some are being tested in clinical trials (by researchers). It is suggested that patients with salivary gland cancer have their treatment planned and managed by a team of doctors who are experts in treating head and neck cancer. Although treatment depends on the stage of the cancer, typically the following three treatments are used: (1) surgery, (2) radiation therapy, and (3) chemotherapy.  
For more information, visit GARD.