Salivary gland cancer is malignant (abnormal) growth of salivary gland cells. This type of cancer is part of the so-called head and neck cancer (this group of cancer includes cancer in the oral cavity, salivary glands, paranasal sinuses, nasal cavity, pharynx, larynx, neck lymph nodes).
Salivary glands make saliva. There are small and large glands, located in the lips, cheeks, mouth, throat, under, in front of, behind, and under the jaw. The large glands, that are in pairs, are: parotid, sublingual, and submandibular. The small ones are not named.
Salivary gland cancer mostly attacks the parotid gland, located in front of the ear.
Salivary gland tumours are rare. Benign tumours of the parotid gland are more common.
The symptoms of salivary gland cancer are:
- swelling near the jaw, neck, or the mouth
- painless lump in the affected area
- difficulty swallowing
- difficulty in opening the mouth wide
- difficulty moving one side of the face, known as facial nerve palsy
The cause of salivary gland cancer is not exactly known. As in all other types of cancer, there are mutations in the DNA, that make the cells multiply and grow rapidly, invading the close tissues or distant areas of the body (metastasize).
On the other hand, it is known that one of the salivary gland cancer symptoms, swelling, can be caused by:
- liver cirrhosis
- salivary gland infections
- abdominal surgery
- salivary duct stones
- Sjogren syndrome
There are several types of this cancer, classified according to the type of cell attacked. Those are:
- Acinic cell carcinoma
- Adenoid cystic carcinoma
- Clear cell carcinoma
- Malignant mixed tumor
- Mucoepidermoid carcinoma
- Oncocytic carcinoma
- Polymorphous low-grade adenocarcinoma
- Salivary duct carcinoma
- Squamous cell carcinoma
The risks of developing a salivary gland cancer include:
- Age – diagnosed in older patients
- Exposure to radiation – for e.g. radiation therapy for head and neck cancers
- Exposure to chemicals, such as asbestos
- Viruses – Epstein-Barr virus, HIV
- Tobacco, but in a non-cancerous type of salivary gland tumour, called Warthin tumor
The complications that may arise, beyond the possible spread of the tumour to other organs, is an injury of the facial nerve that controls movement, which can happen during surgery.