What is salivary gland cancer?

Salivary gland cancer is a very rare malignant tumour disease that affects the area of the pancreas. It is particularly common in the parotid gland (parotid carcinoma). Salivary gland cancer can include any age category, but affects patients between 50 and 70 years of age more frequently than average. Children are affected rather less frequently. Salivary gland cancer tends to form again or metastasise after successful treatment.

What are the different types of salivary gland cancer?

There are different types of salivary glands, such as the major cephalic gland, the submaxillary gland or the parotid gland. Each of these consists of many different types of cells, which can in principle develop into a tumour. Doctors distinguish between the different types of salivary gland cancer according to the respective cell type. Salivary gland cancers occur particularly often in the parotid gland and grow relatively quickly. They can infiltrate the surrounding tissue and may even metastasise to the neighbouring lymph nodes or lungs. Examples are:

• adenocystic carcinoma (ACC): is an aggressive form of tumour that forms along the facial nerves, called the facial nerve. It forms metastases early on, usually to the lungs or bones, and in some cases forms again after successful treatment (recurrence).
• mucoepidermoid carcinoma (MEC): is the most common form of salivary gland carcinoma and usually develops in the parotid glands, but can also occur less frequently in the minor salivary glands in the mouth or the sublingual gland. People around the age of 50 are more likely than average to develop MEK, and women are affected more often than men. If it develops in children or adolescents, it takes a less aggressive course than in adults. Characteristic of a MEK is its barely perceptible demarcation from the neighbouring tissue and its tendency to grow into the surrounding tissue.
• acinar cell carcinoma: is a malignant tumour that develops from certain glandular cells, the so-called acinar cells, of the salivary gland. Acinar cell carcinoma is more common in younger patients than in other forms of salivary gland cancer. Acinar cell carcinoma is the second most common form of salivary gland cancer in children.

What causes salivary gland cancer to form?

As with other types of cancer, salivary gland cancer develops when originally healthy cells change. Due to this change, the cells suddenly multiply unhindered and displace the healthy tissue. The exact cause of this transformation is not yet known. However, doctors assume that several factors interact in the development of salivary gland cancer. However, a genetic disposition is excluded.

Patients who received radiation therapy in the head and neck area in childhood have an increased risk of developing salivary gland cancer. But smoking and contact with certain viruses such as the Epstein-Barr virus or the human papilloma virus (HPV), as well as ionising radiation, can also increase the likelihood of developing salivary gland cancer.

What are the symptoms of salivary gland cancer?

Salivary gland cancer is characterised by increasing swelling of the salivary gland, which does not cause pain at first. As the disease progresses, both the swelling and the discomfort can increase. Due to the size of the tumour, the following symptoms may occur:

• Difficulty swallowing,
• Difficulty speaking,
• dry mouth,
• Tingling and/or numbness up to unilateral facial paralysis (paraesthesia), if the facial nerve (Nervus facialis), which runs through the parotid gland, is affected.

How is salivary gland cancer diagnosed?

If salivary gland cancer is suspected, the patient should consult an ear, nose and throat specialist. The doctor will take the patient's medical history in an initial consultation and ask about the existing complaints. The patient is then examined clinically, paying particular attention to possible changes in the facial area and the oral cavity. If there are palpable swellings or nodules in the salivary glands or in the area of the cervical lymph nodes, these may be the first signs of a possible tumour.

The usual imaging methods such as ultrasound (sonography) and computer (CT) and magnetic resonance imaging (MRI) are used to make a reliable diagnosis. These procedures can determine the tumour's condition, but also clarify the question of whether the tumour has already grown into the surrounding tissue and/or possibly even formed metastases. In addition, a blood test can also show the patient's general state of health. However, there are no specific blood values that could indicate salivary gland cancer.

How is salivary gland cancer treated?

Regardless of whether it is a benign or malignant tumour of the salivary gland, the first choice of treatment is always complete surgical removal. This is because even benign tumours can become malignant over time. During the operation, the salivary gland is removed either completely (paroidectomy) or partially (partial paroidectomy). If the tumour can be removed completely, the treatment is usually complete, at least in childhood and adolescence. If, on the other hand, the tumour has already spread into the surrounding tissue, especially into the neighbouring lymph nodes, it is necessary to remove these as well. Doctors refer to this very extensive operation as a "neck dissection". In some cases, it may also make sense to have radiotherapy after the operation.

What is the prognosis for salivary gland cancer?

Salivary gland cancer has a good prognosis in most cases and can be cured. The chances of cure depend on various factors. As a rule, the survival rate is very high, as long as:

• the salivary gland carcinoma is well demarcated from the adjacent tissue and has not grown into the tissue,
• the tumour grows slowly,
• the tumour is located in the outer area of the parotid gland.