Salivary gland cancer
The major salivary glands consist of three sets of paired major glands: the two parotid glands (near the angle of the mandible), the two submandibular glands (beneath the mandible) and the two sublingual glands (beneath the floor of the mouth) and, in addition, many minor salivary glands which are scattered submucosally (under the lining), throughout the mouth, oropharynx (throat), palate and occasionally the nose.
The various different salivary glands are prone to a variety of conditions and diseases, including a huge and bewildering range of salivary neoplasms (tumours). The majority (70 – 80 %) of salivary gland lumps, masses and tumours are benign (not malignant). The incidence of malignant salivary tumours in Europe is 1.2 per 100,000, so these are very rare.
There are certain situations where there should be an increased suspicion of malignancy. Fast growing lumps, pain, sensory or motor nerve symptoms are all suspicious of a lump being malignant rather than benign. The site of a lump is also a risk factor for malignancy; in general
- 15% of parotid gland tumours are malignant
- 35% of submandibular gland tumours are malignant
- 50% of minor salivary gland tumours are malignant
- 85% of sublingual gland tumours are malignant
A parotid mass greater than 4 cm is said to have a higher risk of being malignant.