Salivary gland cancer

The salivary glands, located in and around the mouth and throat, are responsible for producing saliva. This aids digestion and adds moisture to the mouth, making it easier to chew and swallow.

Salivary gland cancer is rare, with three out of 100,000 adults estimated to be diagnosed in 2024, according to the American Cancer Society. The five-year survival rates for salivary gland cancer differ based on how much the cancer has spread. ASCO reports the overall five-year survival rate as 75 percent, and the breakdown of five-year survival rates by spread as follows:

• 95 percent for localized cancer (contained within the salivary gland)
• 69 percent for regional cancer (spread to nearby areas or lymph nodes)
• 44 percent for metastasized cancer (spread to faraway places in the body)

This cancer tends to affect older patients, with the average age of diagnosis being 64 years old.

What is salivary gland cancer?

Salivary gland cancer occurs when cancer cells originate within the salivary glands. It’s a type of head and neck cancer. Salivary glands make saliva, which contains enzymes necessary for digestion. The body has two types of salivary glands: major and minor. Cancer may begin in any of the salivary glands.

The major salivary glands include:

• Parotid glands are the largest salivary glands, and they are found in front of the ears. These glands are where most salivary gland tumors begin, both noncancerous and cancerous.
• Submandibular glands are smaller and found below the jaw. About one or two out of 10 tumors begin here, with around half of them being cancerous.
• Sublingual glands are the smallest gland type and located under the floor of the mouth and below each side of the tongue. It’s rare for tumors to form in these glands.

There are also hundreds of minor glands, but it’s rarer for tumors to begin in these glands. When they do, they tend to be cancerous and often start on the roof of the mouth.

Salivary gland cancer causes and risk factors

The exact cause of most salivary gland cancers is still unknown to researchers. However, certain risk factors that may increase the chances of developing the disease have been identified.

Risk factors for salivary gland cancer include:

• Gender. This cancer occurs more often in men than women.
• Age. Risk increases as the person gets older.
• Radiation exposure. Those exposed to radiation, either as part of medical treatment or due to their workplace, may face an increased risk.
• Family history. Although uncommon, there may sometimes be a genetic link to salivary gland cancer.

Studies have shown that a link may also exist between salivary gland cancer and certain metals and manufacturing materials, tobacco and alcohol use, and diet. Still, additional research needs to be done.

Symptoms

Often, people don’t notice any symptoms. Rather, the cancer is found during a routine examination by a doctor or dentist. If you notice any of the following symptoms, see your doctor:

• Lump around the jaw, cheek, lip or mouth
• Difficulty swallowing or opening mouth completely
• Fluid draining from the ear
• Persistent pain around the face, ear or neck
• Weakness or numbness in a part of the face

The above symptoms don’t necessarily mean cancer, but it’s important to visit a doctor for more information.

Diagnosis

During an appointment, a doctor may first ask about the patient’s medical history and background to assess whether there are risk factors for salivary gland cancer. A physical exam may be conducted to check the mouth, jaw, ears and face.

Doctors have a number of tests that may be used to diagnose or rule out cancer.

Imaging tests, for example, provide a clearer picture of the mouth and jaw.

• X-ray: Taking X-rays of the jaw, mouth and teeth may help doctors look for a tumor. If there’s concern that cancer has spread to the lungs, then a chest X-ray may be performed.
• CT scan: A computed tomography (CT) scan takes internal photos of the body, which is useful in looking for tumors. Before the procedure, the patient is given a dye (via a drink or injection) that makes it easier for doctors to see the results.
• MRI scan: Using radio waves and magnets, a magnetic resonance imaging (MRI) scan is another tool for taking photos within the body. A dye is often used before MRI scans as well.
• PET scan: A positron emission tomography (PET) scan looks for areas in the body with high cellular activity, indicating cancer may be present.

After reviewing the imaging tests, the doctor may order a biopsy, which removes tissue from the body. It may be examined under a microscope, looking for cancer cells. Several types of biopsies are used to diagnose salivary gland cancer, including:

• Fine needle aspiration (FNA) biopsy. During an FNA biopsy, the doctor may numb the area over the tumor, then use a hollow needle to remove a small amount of tissue and fluid from the body. FNA biopsies are most commonly done in suspected salivary gland cancers.
• Incisional biopsy: The doctor makes a small incision and removes tissue cells.
• Surgery: If imaging tests suggest that cancer is present, a doctor may recommend skipping the biopsy and going straight to surgery to remove the tumor from the body.

If the biopsy detects cancer cells, the doctor may discuss the next steps, including treatment options. It may be frightening and overwhelming to receive a cancer diagnosis, so patients may want to bring along a relative or support person to the appointment. It’s also important to ask plenty of questions.

Types of salivary gland cancer

Cancer may develop in any of the salivary glands, including the parotid, submandibular and sublingual glands, and the minor glands. During diagnosis, doctors may discuss the cancer’s location and stage.

Staging is a process that determines whether cancer has spread and where it has spread to. Doctors typically provide a staging number between one and four, with larger numbers meaning the cancer is larger in size. The staging number is important, because it helps doctors develop an appropriate treatment plan.

Treatment options

The main treatment options for salivary gland cancer include:

• Surgery
• Radiotherapy
• Chemotherapy

However, new treatment options are being researched and tested through clinical trials.

Doctors create a treatment plan, outlining evidence-informed treatments—keeping in mind that the patient may be treated by a team of different doctors or specialists.

Before beginning any treatment, patients should make sure they fully understand how it works, how much recovery time is needed, and potential side effects.

Surgery: During surgery, a doctor surgically removes the tumor, along with some of the healthy tissue nearby. If the cancer has spread to the lymph nodes, then these may be surgically removed at the same time. An anesthetic is given to prevent discomfort.

Radiation therapy: Radiation uses high-energy X-rays to precisely target and destroy cancer cells. Radiation may be delivered externally or internally.

• With external radiation, the patient is in the room with a radiation machine, which sends radiation to the cancer cells.
• Internal radiation involves inserting a safe radioactive substance (in the form of seeds or needles, for example) in or near the cancer. The radiation then kills the cancer cells over time.

Sometimes, patients have a tumor removed via surgery, but may then undergo radiation to kill any cancer cells left behind.

Chemotherapy: During chemotherapy, drugs are used to stop cancer cells. They may be injected or taken orally, making their way into the bloodstream to travel through the body and either kill cancer cells or stop them from reproducing.

It’s important to remember that all medical treatments have the potential for side effects and risks, so patients should ask their care team for these details and further clarification, if needed. Patients shouldn’t be afraid to ask questions before, during and after treatment.

Sometimes, cancer becomes recurrent, meaning it returns after treatment. If that happens, doctors may present the patient with additional treatment options.