You may not stop to think of it often, but your saliva plays an important role in your mouth. Saliva helps you chew and swallow food and ensures comfort when speaking. It also contains elements that fight germs and protect tooth enamel.
The mouth contains a system of glands tasked with creating saliva. There are three major pairs of salivary glands: the parotid, just in front of the ears; the submandibular, below the jaw; and the sublingual, on the side of the tongue under the floor of the mouth. Additionally, there are hundreds of small salivary glands in the mouth, nose and larynx.
It is possible for tumors to grow in these glands, and for a small percentage of people, these tumors are malignant (cancerous).
If you or a loved one has been diagnosed with salivary gland cancer, you may have a lot of questions. We talked to Trevor G. Hackman, MD, a UNC Health head and neck cancer specialist, to understand what you need to know about salivary gland cancer.
Salivary Gland Cancer Prevalence
Salivary gland cancer is a type of head and neck cancer. Compared with other types of cancer, head and neck cancers are rare, comprising about 4 percent of all cancers in the United States. Salivary gland cancer accounts for 6 to 8 percent of head and neck cancers.
An estimated 2,000 to 2,500 new cases of salivary gland cancer are diagnosed in the United States each year.
“A patient will want to know why they have a certain kind of cancer, but because salivary gland cancer is so rare, we don’t always know,” Dr. Hackman says. “We lack the large number of patients needed to conduct research on risk factors or new therapies.”
Types of Salivary Gland Cancer
The most common type of salivary gland cancer is mucoepidermoid carcinoma. If you’ve received this diagnosis, you might hear your doctor discussing the tumor grade, which describes the cells in the cancer and may indicate the risk for the cancer to spread.
- A low-grade cancer may have a risk for local recurrence but is not known to spread.
- An intermediate-grade cancer may have the ability to spread beyond the salivary glands.
- A high-grade cancer invades structures (such as nerves) and spreads more aggressively.
Adenoid cystic carcinoma is the second most common type of salivary gland cancer.
“This one is unusual because it has a habit of skipping directly from the primary site of the gland and going straight for the lungs, whereas other cancers typically invade lymph nodes first,” Dr. Hackman says. “It also gets on nerve endings and rides them like a highway to the brainstem and the brain, so a radiation oncologist will design the radiation fields that also include these nerves all the way to the brainstem for maximum control of the cancer.”
This type of cancer is known for delayed recurrence, even decades after initial treatment, which means long-term surveillance is necessary.
Other common types of salivary gland cancer include acinic cell carcinoma, polymorphous adenocarcinoma and secretory carcinoma.
Salivary Gland Cancer Symptoms
Salivary gland cancer symptoms usually start as a slow growth of a mass. You may feel a lump in your mouth, over your jaw or in your neck, and as the tumor grows and invades local structures, you can experience pain in the face, neck, jaw or mouth. In more advanced cases, you may have issues opening your mouth or swallowing. If the cancer is affecting the parotid gland, you may experience gradual facial paralysis.
“As opposed to Bell’s palsy, which is a sudden complete facial paralysis,” Dr. Hackman says, “the facial paralysis seen with parotid cancer typically starts with a gradual paralysis of one isolated segment of the face and then slowly progresses to involve more of the face over time.”
“For most patients, tumors in the salivary glands are benign [noncancerous], and it can sometimes be difficult to give a definitive diagnosis with the needle biopsy,” Dr. Hackman says.
Imaging scans will also reveal the extent to which the tumor’s borders have crept into tissues and lymph nodes, which will affect the treatment plan.
Salivary Gland Cancer Treatment
Surgery to remove the tumor is the primary treatment for salivary gland cancer. If the tumor has spread into nerves or lymph nodes, surgery is often followed by radiation therapy. Chemotherapy is rarely beneficial in salivary gland cancer, according to Dr. Hackman, so it is only used in certain situations.
“Treatment is a marathon, not a sprint,” Dr. Hackman says, noting that the surgery and radiation process is usually three months, with recovery taking another three months or more.
During that time, you may experience significant side effects from the treatment that can affect daily quality of life, particularly speech and swallowing function.
Surgery to remove a salivary gland cancer may affect nerves that control facial function, and it could take time to know whether the results are temporary or permanent.
“If the facial nerve is involved by the cancer and has to be removed, immediately after surgery it will look like someone has suffered a stroke,” Dr. Hackman says. “Fortunately, there are options to restore appearance and facial movement, but it may take more than a year and multiple procedures to reach this goal.”
Radiation for salivary gland cancer treatment often results in dry mouth and ulcers, which can last between six weeks and three months. Some people experience disturbances in taste, while others may have stiffness in mouth tissue that can make it difficult to eat. Again, it will take time to determine whether these effects are short term or long term.
Dr. Hackman urges anyone who receives a salivary gland cancer diagnosis that will require radiation after surgery to see a dentist before beginning treatment, as radiation will have long-term effects on teeth and jaw health.
“The treatment will decrease saliva, which means you lose the protection that saliva provides to your teeth, and it will damage tissues and blood around the tooth,” he says. “With decreased saliva or blood supply to the teeth and jaw, unhealthy teeth will wither away more quickly, putting the jaw at risk for infections, but you won’t be able to pull them without risking necrosis and removal of the jawbone.”
If you have unhealthy teeth, get them extracted before treatment to avoid these issues.
Worried that a lump might be cancer? Talk to your doctor and have it checked out. Need a doctor? Find one near you.