Salivary glands produce saliva, which keeps the mouth moist and supports digestion. Salivary gland cancer is a rare cancer that starts in the tissue of one of these glands.

Salivary gland cancer is responsible for less than 1% of all cancers In the United States, affecting 1 in every 100,000 people.

This article takes a closer look at salivary gland cancer, including its symptoms, treatments, and risk factors.

The mouth contains major and minor salivary glands. Salivary gland cancer occurs when one of these glands develops a cancerous tumor.

There are three pairs of major salivary glands: the parotid, sublingual, and submandibular.

The parotid glands are the largest salivary glands, positioned just in front of each ear. A tumor is most likely to develop here. While most tumors that grow here are benign, this is also the starting place for most malignant salivary gland tumors.

The sublingual glands sit under the tongue and are the smallest of the major salivary glands. It is rare for a tumor to start in these glands.

The submandibular glands are just below the jaw. According to the American Cancer Society (ACS), around 10–20% of tumors begin here, and roughly 50% are malignant.

There are also hundreds of microscopic minor salivary glands all around the mouth. Locations include:

  • the sinuses
  • the tongue
  • inside the cheeks
  • the nose
  • the larynx
  • voice box

Tumors are less likely to occur in these minor glands, but they are more likely to be malignant if they develop.

Salivary gland tumors can include blood and lymphatic system cancers, such as non-Hodgkin lymphoma.

Benign tumors do not spread locally or to distant parts of the body. However, a benign tumor might become malignant if left untreated or after incomplete removal.

Malignant tumors are more aggressive and have a higher risk of metastasis, or spreading. Surgery often provides a complete cure.

Learn more about benign and malignant tumors here.

A person who has salivary gland cancer may experience:

  • difficulties in opening their mouth completely
  • weak facial muscles on one side of the face
  • a swelling or lump around the jaw, mouth, or neck area
  • a noticeable difference in the shape of one side of the neck or face
  • a numb feeling in part of the face
  • constant pain in the salivary gland

People should see a doctor about any painless lumps that do not directly result from a known infection.

Salivary gland cancer can occur in any of the salivary glands.

The prognosis for people with salivary gland cancer depends on how far the cancer has spread from its original site.

The ACS uses a 5-year survival rate as a guide for a person’s outlook after a cancer diagnosis. This compares the likelihood that a person with cancer will live for 5 years after diagnosis with that of a person who does not have cancer.

A person’s outlook will depend on which SEER stage a doctor diagnoses the cancer. SEER is the National Cancer Institute’s (NCI) Surveillance, Epidemiology, and End Results program.

These vary depending on how the cancer has spread.

  • Localized cancer: If a doctor identifies and treats salivary gland cancer before it spreads from its original site, an individual is 95% as likely to survive for 5 years after diagnosis.
  • Regional cancer: If this cancer spreads into nearby tissue, the rate reduces to 69%.
  • Distant cancer: If the cancer spreads to distant sites, the 5-year survival rate is 44%.

However, these vary depending on age, overall health, and the success of treatment. Only a doctor will be able to predict an accurate outlook.

Early diagnosis and treatment are the best ways to improve a person’s outlook for salivary gland cancer.

Learn about the most curable cancers here.

Scientists do not know the exact cause of salivary gland cancer. They think it results from changes in a person’s DNA, and researchers are yet to identify its causes.

However, several factors can increase the risk of developing salivary gland cancer.

  • Radiation exposure: People who have undergone radiation therapy for previous head and neck cancers may have a higher chance of developing salivary gland cancer later in life.
  • Age: As people age, their risk of developing salivary cancers increases.
  • Gender: Males are more likely to develop salivary cancers than females.
  • Pollutants: Workplace exposure to substances such as nickel alloy dust and silica dust may also be a factor.
  • Family history: Genetic factors can also increase the risk. However, confirmed instances of this are rare.

Learn more about head and neck cancer here.

Many types of cancer can develop in the salivary glands. Some are adenocarcinomas, which form in substance-secreting cells. Salivary gland cancers include:

  • Mucoepidermoid carcinomas: These are the most common form of salivary gland cancer. They often grow slowly and mainly start in the parotid glands.
  • Adenoid cystic carcinomas: These tumors grow slowly but may be difficult to cure because they grow along nerves.
  • Acinic cell carcinomas: These carcinomas tend to occur at a younger age and grow slowly.
  • Polymorphous low-grade adenocarcinomas: This type of cancer is typically curable and forms in the minor salivary glands.
  • Other epithelial lesions: This classification of different cancer types includes intercalated duct hyperplasia and nodular oncocytic hyperplasia.

Sometimes, doctors can identify that a person has an adenocarcinoma but cannot identify the type. These are known as adenocarcinoma NOS (not otherwise specified)), and are most common in the parotid and minor salivary glands.

Other rare types of cancer might also develop. For example, sarcomas, which are cancers of connective tissue cells, may develop, and people living with Sjögren’s syndrome may develop a Non-Hodgkin lymphoma in the salivary gland.

Learn more about cancer here.

To diagnose salivary gland cancer, a doctor will ask the person about their medical history and examine the sides of the face, the mouth, and the area around the jaw. If they notice any swelling in the lymph nodes, this could be a sign of cancer.

However, the swelling of lymph nodes is often not due to cancer and may result from infection or viral inflammation.

Muscle weakness or numbness in the face could indicate that the cancer has spread to the nerves.

The doctor may request imaging tests to determine the location and spread of any disease. These tests may include X-rays, CT, and MRI scans.

Doctors may also recommend a biopsy to collect and analyze salivary gland tissue. In an incisional biopsy, the specialist makes a small cut and removes a sample of the tumor, which they send to a lab for examination.

Depending on the initial findings, they may recommend surgery to remove and test the whole tumor.

Learn more about different types of tumors here.

Treatment for salivary cancer often involves surgery, radiation therapy, chemotherapy, or a combination of these.

Surgery

Surgery is typically the primary form of treatment for salivary gland cancer. The surgical team may need to remove the whole salivary gland, along with any nerves and ducts to which the cancer may have spread.

If the tumor is small and easy to access, the surgeon may remove just the tumor and a small amount of surrounding tissue.

Side effects

Complications of surgery are rare. However, they may include:

  • adverse reactions to anesthetic
  • slow wound healing
  • infection
  • excessive bleeding

Nerve damage may cause one side of a person’s face to droop, and an individual may have difficulties swallowing or talking after surgery.

In some cases, a person can have reconstructive surgery, and a speech therapist can help restore some lost eating and speaking functions.

Gustatory sweating, or Frey Syndrome, occurs when nerves grow back in an unusual way. This growth can lead to sweating over some areas of the face when chewing. Medical professionals may recommend further surgery to treat this.

Learn more about sweating after eating here.

Radiation

In radiation therapy, the cancer care team directs high-powered energy particles or beams at a tumor to slow the growth of or destroy cancer cells.

The most common type of radiation therapy for salivary gland cancer is external beam radiation therapy. It provides an intense level of radiation.

A person will usually need radiation treatment every day for 5 days a week. The course of treatment will last for up to 7 weeks.

Newer types of radiation therapy that may be more successful include accelerated hyperfractionated radiation. This breaks treatments up into several smaller doses per day.

A cancer care team might also administer radiosensitizer medications. These make a tumor more sensitive to radiation therapy, meaning that it kills more cancer cells.

Side effects

The adverse effects of radiation therapy generally include:

These typically resolve after treatment. Radiation therapy can, however, have effects on other parts of the head and neck, including:

  • dry mouth due to decreased saliva production
  • throat and mouth sores
  • dry, sore throat
  • difficulty swallowing
  • total or partial loss of taste
  • bone pain and damage
  • worsening of dental problems
  • damage to the thyroid gland
  • ringing or sensation of fullness in the ears

Learn about the differences between radiation and chemotherapy here.

Chemotherapy

A doctor may recommend chemotherapy or other anti-cancer treatments if the cancer has spread to other parts of the body. A person’s therapy plan may still include radiation therapy but will not always do so.

A variety of drugs are available that a cancer care team can administer on their own or with other drugs, such as 5-fluorouracil (5-FU) or carboplatin.

Side effects

Chemotherapy kills cancer cells, but it can also affect some healthy cells, such as hair follicles and cells in the lining of the mouth. Common side effects include:

  • reduced appetite, nausea, and vomiting
  • low white and red blood cell count, increasing the risk of infections and fatigue
  • low blood platelet count, leading to easier bruising
  • hair loss
  • mouth sores

After completing treatment, a doctor will continue to monitor the individual closely. It is important to attend all follow-up appointments as this can help to minimize any side effects of treatment and detect any signs of a cancer recurrence early.

Learn more about the success rates of chemotherapy for different cancers here.

Preventing salivary gland cancer is difficult because doctors do not know what causes it.

Avoiding tobacco and alcohol may slightly reduce the risk of this rare cancer and many other more common types.

People working in environments where there is nickel alloy dust, silica dust, or radioactive substances should use appropriate protection.

Salivary gland cancer can occur in any saliva glands around a person’s mouth.

Researchers have not identified the exact cause of salivary gland cancer, but exposure to radiation and a person’s age and gender can increase their risk of developing it.

Treatment options include surgery, radiation therapy, and chemotherapy. Typically, the earlier a doctor diagnoses salivary gland cancer, the better a person’s outlook is.