The submandibular glands are part of the system of salivary glands, which are found throughout the tissues of the mouth. There are two submandibular glands, the right and left, and they lie deep to the jaw bone (mandible) just below and behind the level of the canine teeth. They are about 2.5cm (one inch) in size.

Cancers of the submandibular gland are very uncommon with only about 100 new cases every year in the UK. When they do occur, adenoid cystic carcinomas are the commonest type of tumour in the submandibular gland.

Adenoid cystic cancers are typically very slow growing and there may be a history of many months of pain and swelling of the gland before the diagnosis is finally made.

Another characteristic of these particular cancers is that they tend to spread along the paths of the nearby nerves (which is one reason why they cause pain). Often invisible, microscopic, columns of the cancer cells can extend for some distance.

Surgery is the usual form of treatment. Because of the likelihood of tumour cells tracking along the nerves around the gland, this often involves quite a major operation to try and clear the cancer as completely as possible. If after surgery, examination of the tumour suggests it has not been completely removed then radiotherapy is usually given to try and prevent further problems.

Although this treatment is often successful somewhere between one third to one half of patients will develop distant spread of the cancer at some time in the future. This is most often to the lungs or occasionally the liver. When this happens the secondary cancers, like the primary growth in the submandibular gland usually progress very slowly. This type of cancer has so far proved very resistant to chemotherapy treatment, but they often take years to appear and even when they have been discovered it may be many more years before they actually cause significant problems.