Salivary Gland Cancer

Salivary gland cancer is the collective name for the malignant tumours that develop in the salivary glands. It is uncommon among head and neck cancers and has many different subtypes; these range widely in behaviour, from slow-growing to rapidly progressing. When diagnosed at an early stage, treatment is usually limited to surgery.

Types

Salivary gland cancers are named according to the type of cell they arise from. The most frequently encountered types are mucoepidermoid carcinoma, adenoid cystic carcinoma, acinic cell carcinoma and adenocarcinoma. Cancers can also develop on the basis of a long-standing benign tumour (pleomorphic adenoma). Each type is further classified as low, intermediate or high grade; the grade indicates how quickly the tumour tends to grow and spread.

Symptoms

• A growing, hardening mass in front of the ear, under the jaw or inside the mouth
• Pain in the mass or fixation to the surrounding tissue
• Weakness on one side of the face, inability to close the eye, numbness
• Difficulty opening the mouth, difficulty swallowing
• Palpable lymph nodes in the neck

None of these symptoms on its own means cancer; however, when they appear together or rapidly, evaluation should not be delayed.

Diagnosis and staging

The diagnostic process begins with examination, ultrasound and fine-needle aspiration biopsy. When cancer is suspected, magnetic resonance imaging (MRI) shows the depth of the tumour and its relationship to the nerves, while computed tomography (CT) shows bone involvement and the lymph nodes of the neck. If considered necessary, PET-CT may be requested to look for distant spread. The cancer is classified from stage I to stage IV according to the size of the tumour, lymph node involvement and whether there is distant spread. The stage determines the treatment plan and the frequency of follow-up.

Treatment

• Surgery: This is the main treatment method. The tumour is removed together with the gland, leaving a margin of healthy tissue around it. In the parotid gland, the facial nerve is preserved as long as it is not involved by the tumour. If there is spread to the lymph nodes of the neck or the tumour is high risk, a neck dissection is added.
• Radiotherapy: It is given after surgery for high-grade tumours, for nerve or lymph node involvement, and when the surgical margins are close. In tumours that cannot be operated on, it can also be used on its own.
• Drug treatments: Chemotherapy and targeted therapies come into consideration in selected advanced-stage cases; their role in salivary gland cancers is limited and is assessed individually.

If the facial nerve has to be removed because of the tumour, nerve repair or additional procedures that support facial movement can be planned during the same operation.

Follow-up after treatment

After treatment is completed, regular check-ups are important for catching a recurrence early. Check-ups are more frequent in the first years and less frequent in later years; imaging is added to the examination when needed. Because some types can recur even years later, follow-up is long term.

When should you see a doctor?

For a salivary gland mass that is growing, painful or hardening, newly appearing weakness of the facial muscles, or palpable swellings in the neck, it is advisable to ask for an evaluation without delay.