Salivary Gland Cancer

Salivary gland cancer is a malignant tumor that arises in one or more of the salivary glands – the organs responsible for producing saliva, which lubricates the mouth, aids digestion, and helps protect against oral infection.

The salivary glands are divided into two categories. The three pairs of major salivary glands are the parotid glands (located in front of each ear), the submandibular glands (beneath the jawbone), and the sublingual glands (under the floor of the mouth). In addition, there are hundreds of minor salivary glands distributed throughout the lining of the mouth, palate, tongue, lips, cheeks, sinuses, and throat.

Salivary gland cancer is rare, accounting for less than 1% of all head and neck tumors. Salivary gland tumors may be benign (noncancerous) or malignant (cancerous), and both types can occur in any of the salivary glands. Most tumors – both benign and malignant – originate in the parotid glands.

Many salivary gland tumors – both benign and malignant – initially present as a painless lump. The absence of pain does not indicate that a tumor is benign. As the disease progresses, additional symptoms may develop:

Painless lump or swelling

• It is the most common presenting sign. May be felt in front of the ear (parotid), below the jaw (submandibular), under the tongue, or elsewhere in the mouth or neck.

Pain

• When a tumor enlarges or invades adjacent structures, persistent pain may develop in the face, jaw, neck, or mouth. Pain may be aggravated by eating, as food stimulates saliva production.

Facial nerve weakness or paralysis

• Involvement of the facial nerve – which passes through the parotid gland – can cause weakness or paralysis of one side of the face. This is a sign that requires urgent evaluation.

Numbness or tingling

• Tumor invasion of nearby nerves may produce numbness, tingling, or abnormal sensation in the face, mouth, or jaw.

Difficulty opening the mouth (trismus)

• Advanced tumors may restrict jaw movement.

Difficulty swallowing

• Tumors in the submandibular or sublingual region, or large parotid tumors, may impair swallowing.

Bleeding from the mouth

• It is less common and may occur with ulcerated tumors.

Neck mass

• Enlargement of regional lymph nodes due to cancer spread may produce a palpable lump in the neck.
  
  

* Important: A painless lump in the face, jaw, or neck that persists or grows should be evaluated by a specialist. Not all lumps are cancerous, but early assessment is essential for accurate diagnosis.

The exact cause of salivary gland cancer is not known. It arises from changes in the DNA of salivary gland cells that cause abnormal cell growth, but the specific triggers for these changes have not been fully identified. Several factors have been associated with increased risk.

Age and sex

• Salivary gland cancer occurs more commonly in older adults. Men are more frequently affected than women.

Prior radiation therapy to the head or neck

• A history of radiation treatment to the head or neck region is a recognized risk factor for subsequent salivary gland cancer.

Occupational exposures

• Certain occupational exposures have been associated with elevated risk, including prolonged contact with nickel alloy dust, silica dust, rubber manufacturing, asbestos, and leatherwork. Appropriate protective equipment is recommended in these environments.

Tobacco and alcohol use

• Tobacco use and frequent alcohol consumption have been identified as contributing risk factors.

Family history

• A family history of salivary gland cancer may indicate a genetic predisposition, though familial cases are uncommon.

Pre-existing benign tumors 

• Some benign salivary gland tumors – particularly pleomorphic adenoma – carry a small risk of undergoing malignant transformation over time.

No method is known to reliably prevent salivary gland cancer, as its exact cause has not been established. The following general measures may help reduce overall risk:

• Avoid tobacco products in all forms.
• Limit alcohol consumption.
• Use appropriate protective equipment when working in environments with known occupational exposures (nickel dust, silica, rubber manufacturing).
• Attend regular dental and medical check-ups, which may enable early detection of salivary gland abnormalities.