What Is Salivary Gland Cancer?
Salivary gland cancer refers to cancer that starts in the cells of the salivary glands. Salivary gland cancer is very rare and makes up about 6% of head and neck cancer diagnoses. The salivary glands are glands that produce and secrete saliva, the watery fluid found in the mouth and throat. Saliva has many important functions, including lubricating food and making it easier to chew and swallow, keeping the mouth and teeth clean from food particles, preventing bacteria and infections in the mouth, and starting the digestive process with enzymes that break down food.
There are two main types of salivary glands: major and minor. The major salivary glands include a pair of parotid glands, a pair of submandibular glands, and a pair of sublingual glands. There are also hundreds of microscopic “minor” salivary glands inside the lips, mouth, larynx, sinuses, and other areas. This document focuses mainly on tumors of the major salivary glands, which are much more common. Salivary gland tumors may form in any of the following areas:
- Parotid glands: The parotid glands, the largest of the salivary glands, are located in front of the ear lobes and above the jaw. The parotid glands are the most common site of salivary gland tumors (~75%). Most malignant tumors of the parotid glands are mucoepidermoid carcinomas. These tumors may exhibit different behaviors, so it is important for the doctor to determine the tumor grade to know the severity of the tumor.
- Submandibular glands: The submandibular glands are located inside the lower jaw bone and under the floor of the mouth. Cancer of the submandibular glands is rare and makes up about 10%-20% of all salivary gland cancers. Malignant tumors of the submandibular glands are most often adenoid cystic carcinoma. These tumors are most often slow-growing and not very aggressive. These tumors are likely to metastasize, but even with distant metastasis, patients can survive for 15-20 years.
- Sublingual glands: The sublingual glands are located under the floor of the mouth beneath the tongue. Cancer of the sublingual glands is extremely rare and makes up only about 1% of salivary gland cancers.