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, maintaining dental health, contributing to our sensation of taste, 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 thousands 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%). By far, most parotid gland tumors are benign. The most common type of benign parotid tumor is Pleomorphic Adenoma. Though not as common as benign tumors, malignant tumors of the parotid glands occur with frequency, with most the most common type being, mucoepidermoid carcinoma. This type of malignant tumors exhibit different behaviors, which depend largely on its appearance under the microscope, so it is important for your doctor to determine the tumor grade to know the severity of the tumor.

• Submandibular glands: The submandibular glands are located underneath the lower jaw bone and extend into the oral cavity under the floor of the mouth along both sides of the tongue. Cancer of the submandibular glands occurs less frequently than parotid gland tumors. Submandibular gland tumors make up about 10%-20% of all salivary gland cancers. Similar to the parotid gland, benign tumors are the most common type of cancerous growths for the submandibular gland, yet malignant tumors of the submandibular glands take a different pattern and are most often of the adenoid cystic carcinoma subtype. These tumors are typically slow-growing. Yet despite their slow growth patterns, these tumors have high rates of distant metastasis, particularly to the lung. Therefore patients with adenoid cystic carcinomas need to be vigilant about cancer check ups even 15-20 years after their treatment.

• 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.