Developed and Authored by the AHNS Salivary Gland Section:
authors – Danny Enepekides, MD, too Ameya Asarkar + other 3
What is a salivary gland?
Salivary glands make saliva (spit). Your body has 3 paired major salivary glands (parotid, submandibular, and sublingual) that create most of the saliva in your mouth and throat. There are about 500 minor salivary glands which are found under the surface of the mucosa (pink tissue lining in your mouth and throat). Saliva is a complex watery mix of proteins, salts, and immune factors. Keeping your mouth clean, helping with speaking and swallowing, and digesting food are some things that saliva does. Adults make about 1.5 quarts of saliva per day.
What symptoms can salivary gland tumors cause?
- A lump or a mass near your ear, neck, jaw or mouth, lip which does not go away
- Pain in the mouth, along the jaw, neck which does not go away especially near the ear or below the jaw
- Difficulty in opening the mouth widely
- Sudden or gradual numbness or weakness in one part of the face like inability to close the eye, droopy lip, or crooked smile.
What tests might be used to diagnose a salivary gland tumor?
- History and Physical Examination
The doctor will ask about your symptoms, when they began, and how bad they are. Next will be a thorough physical exam. The doctor will feel the lumps under your skin, or the sore area. Your mouth, areas of your face, ears, and jaw, will be carefully examined as well. The doctor will evaluate for any numbness of the skin and weakness in the muscles of your face and neck.
- Imaging- Ultrasound; computed tomography (CT) scan; magnetic resonance imaging (MRI)
Once the doctor determines which of the salivary glands have been affected, they may further evaluate the size, shape, and location of the tumor with an imaging tool like ultrasound, CT scan or an MRI.
Imaging helps show the border between the salivary tumor and normal structures. During a CT scan or MRI, dye may be injected into your vein to allow the tumor to be more easily seen on the image. Imaging can also help to identify any lymph nodes in the neck which might contain cancer.
- Fine needle aspiration (FNA) biopsy/core needle biopsy
FNA is a method to collect a sample of the tumor for diagnosis. A needle is passed into the tumor to remove some cells. The skin and tissue over the tumor may be numbed first. Sometimes this procedure is done using ultrasound or CT scan to guide the needle into the right place. A pathologist will look at the cells to determine whether the growth is benign (not cancer) or malignant (cancer). There is no risk of spread of tumor from an FNA. Knowing the tumor type might help with deciding the best way to treat it.
How common are salivary gland tumors?
Salivary gland tumors are rare. Less than 5% (1 out of 20) of head and neck tumors come from the salivary glands. Most salivary gland tumors come from the parotid gland, which is located below the skin of the cheek, and most of these tumors are benign (not cancer). Salivary gland tumors in submandibular gland (located under the jaw) or minor salivary glands (located under the tongue in the mouth) are less common. These tumors are more likely to be cancerous than parotid tumors.
Only about 1 out of 100,000 people in the United States will develop a salivary gland cancer each year. These cancers arise most commonly in people age 40 and above. Less than 5 % of salivary gland cancers affect people younger than 18 years old. Men and women both get salivary tumors at about the same rate.
What causes salivary gland tumors?
We do not know exactly why some people get salivary gland tumors. Some risk factors that have been studied are exposures to radiation, silica dust, or rubber chemicals. Viruses like Epstein-Barr Virus (EBV) and Human Papilloma Virus (HPV) may play a role in some salivary gland cancers. Smoking likely causes some benign salivary tumors. For most tumors, there is no cause identified.
What are the most common types of salivary tumors?
Benign: pleomorphic adenoma, Warthin’s tumor, benign cyst, oncocytoma
Cancer: mucoepidermoid carcinoma, adenoid cystic carcinoma, adenocarcinoma, malignant mixed tumor, acinic cell carcinoma
How are benign salivary gland tumors treated?
Most benign salivary gland tumors are removed with surgery. Surgical removal makes sure that the tumor is not cancer and treats discomfort or cosmetic changes from tumor growth. Surgery is usually done in the operating room under general anesthesia. The extent and complexity of surgery will depend on the location and size of the tumor. In general, the tumor is removed with a small amount of normal gland tissue around it to make sure that it does not grow back.
Pleomorphic adenoma is the most common benign salivary tumor. Most of these tumors should be removed because they tend to grow over time and can cause discomfort as they get bigger. There is also a chance they can change into a cancer; the risk is around 10% if the tumor is watched for more than 15 years, so most younger people should have the tumor removed. If the whole tumor is not removed, there is a high chance of tumor regrowth, which can be hard to manage.
If surgery is not possible, or if a person has health issues that make going under anesthesia risky, then observation may be ok for certain benign tumors. Imaging may be used to follow a tumor over time, to watch for growth.
Rarely, radiation may be used for a benign salivary tumor if surgery or observation are not feasible. In recurrent pleomorphic adenoma that cannot be removed safely, radiation may be considered.
What are some common side-effects of surgery?
Face sweating while eating (Frey’s Syndrome)
Your face may sweat when eating after parotid surgery. Around 1 out 10 patients will notice this, and many are not bothered by it. Treatments include antiperspirant on the face, injections, and surgery to separate the skin and parotid.
Numbness of the ear is common after surgery. While the numbness may lessen over time, patients should be careful of piercings or very hot or cold exposure, as they may not feel an injury. Usually after 6-12 months only the ear lobe remains numb.
Change in looks
Depending on the amount of tissue removed, one side of the face may look different than the other (asymmetry). In most cases this is not noticeable to others. Even when the surgical site is reconstructed there may be long term asymmetry as the area heals and changes over time.
What are some risks of surgery?
Loss of face movement (facial nerve injury)
The risk of nerve injury will depend on the reason for surgery. In some cases, the nerve may need to be removed if involved with cancer. In general, the risk of permanent weakness is very low, around 1%, and the risk of temporary weakness is around 10-20%. If the nerve is fully intact (not cut), it can recover, but it may take 6 to 9 months.
Proper care for patients with facial weakness is very important. Eye care, including lubricants and drops, is needed to keep the eye healthy if it cannot close on its own. In the case of permanent loss of movement, surgeries may be done to help with functions like eye closure and smiling.
Saliva collection / Saliva leakage
The cut edge of the parotid can leak saliva which can result in saliva pooling below the skin or leakage of saliva from the wound. This happens in less than 1 out of 10 patients and usually responds to office treatment with needle drainage and pressure dressings. Injections or patches to slow saliva, or surgery, can be used for cases that do not get better.
Salivary tumors can regrow if the tumor is not removed completely.
What follow-up is needed after treatment of a benign salivary gland tumor?
After surgery to remove a benign (not cancer) salivary gland tumor, there will be a follow up visit to make sure everything is healing as expected. CT scans or MRIs are not necessary in most patients after removal of a benign tumor. However, in some cases depending on the location and type of tumor, these tests might be needed to look for regrowth of the tumor.
How is salivary gland cancer staged?
The primary tumor and lymph nodes are staged as follows:
Tx: primary tumor cannot be found
T0: no primary tumor
Tis: cancer in situ (not invading)
T1: Tumor sizes smaller than 2 cm
T2: Tumor size between 2 and 4 cm
T3: Tumor size bigger than 4 cm and/or extending outside of gland
T4a: Tumor invades skin, jawbone, ear canal, facial nerve
T4b: Very advanced tumor invading bone of skull, carotid artery
Nx: nodes cannot be assessed
N0: no lymph node spread
N1: Spread to one lymph node on the same side as tumor, size less than 3 cm
N2: Spread to more than one lymph node, or size between 3 and 6 cm, or spread to other side of neck
N3: Spread to lymph node bigger than 6 cm, or spread outside of the lymph node
M0: no distant spread
M1: distant spread (metastasis)
Stage 0: Tis, N0, M0
Stage I: T1, N0, M0
Stage II: T2, N0, M0
Stage III: T3, N0, M0
T0, T1, T2, T3, N1, M0
Stage IVa T0, T1, T2, T3, N2, M0
T4a, N0,1,2, M0
Stage IVb Any T N3, M0
T4b, Any N, M0
Stage IVc Any T, Any N, M1
What are the recommend treatments for each cancer stage?
Stage I and Stage II (Early Stage): Surgery to remove tumor with removal of lymph nodes for tumors with high grade (aggressive) pathology. Radiation with or without chemotherapy following surgery depending on surgical pathology. Cancers that can be completely removed with clear margins, no lymph node or nerve spread and low grade on pathology, can often be treated with surgery alone.
Radiation with or without chemotherapy can be considered for patients that cannot have surgery.
Stage III and Stage IVa and IVb (Advanced Stage): Surgery to remove tumor with neck dissection to remove lymph nodes. Radiation therapy with possible chemotherapy following surgery.
Radiation with or without chemotherapy can be considered for patients that cannot have surgery.
Stage IVC (metastatic spread)
Surgery may be considered in selected cases to help with symptoms
Radiation may be considered in selected cases to help with symptoms
Recurrence: Surgery to resect recurrent tumor, consider repeat radiation with or without chemotherapy if surgery not possible or if pathology from surgery unfavorable
What is the survival rate for salivary gland cancer?
Survival rates for salivary gland cancer depend on number of factors, most importantly tumor stage and type of tumor.
5-year survival rates are as follows depending on extent of spread of the cancer (SEER 2010-2016):
Local (within the saliva gland): 94%
Local + Regional (spread to neck lymph nodes): 66%
Distant (spread to other parts of the body): 36%
All Stages: 72%
Who treats salivary gland cancers?
Patients with salivary cancers should consider treatment at a multidisciplinary cancer center. These centers offer the advantage of experts from different medical specialties working together on a team. Centers that treat large numbers of patients may achieve better outcomes, especially for rare diseases like salivary gland cancer. The following doctors may be involved in treating a salivary gland cancer:
Head and Neck/Reconstructive Surgeon: Surgery to remove the cancer is often the first step in treatment and may require reconstruction depending on the size/extent/location of the tumor. This may be done by a single surgeon, or a group of surgeons working together.
Radiation Oncologist: Radiation may be used after or instead of surgery to treat a salivary gland cancer.
Medical Oncologist: Chemotherapy is not effective for some salivary cancers but may play a role in the treatment of some advanced or recurrent/metastatic cancers.
Pathologist: Salivary tumors are rare, so experienced pathologists are required to obtain accurate diagnosis and staging.
Radiologist: Image guided needle biopsy may be done by a radiologist. Imaging will often be used to determine the size, extent, and possible spread of the tumor.
Other members of the multidisciplinary team might include: dentist, speech language pathologist, dietician, psychologist, social worker.
What is the role of a Tumor Board in treating salivary gland cancer?
A Multidisciplinary Head and Neck Tumor Board will usually include representatives from surgery, radiation and medical oncology, pathology, and radiology. Dentists, speech language pathologists, dieticians, nurses, and others may also participate. The advantage of having your case discussed at a tumor board is that multiple specialists will work together to ensure the best treatment plan for the individual patient is chosen.
How is salivary gland cancer treated with surgery?
The goal of surgery is to remove the cancer with a margin of normal tissue while protecting important structures like nerves and blood vessels. For advanced stage and/or high-grade tumors, lymph nodes may be removed from the neck during surgery (neck dissection).
Parotidectomy involves removing some or all of the parotid gland. This is usually done through an incision on the face and neck. The facial nerve, which controls facial movement, runs through the parotid gland and should be found and protected while removing the gland. If the nerve is working before surgery, then attempts are made to preserve it unless a cancer involves the nerve.
Submandibular gland removal is performed for submandibular gland tumors. This is usually done through an incision on the neck below the jaw. The lingual nerve, which provides taste and sensation to the tongue is found and protected if possible. The hypoglossal nerve, which controls the tongue muscles, is also found and protected if possible.
Sublingual gland removal is done for sublingual gland tumors. This is most often done through the mouth by making an incision underneath the tongue. The lingual nerve, which provides taste and sensation to the tongue is found and protected if possible. The duct that drains the submandibular gland travels next to the sublingual gland and is found and protected if possible.
Minor salivary gland removal is done for minor salivary gland tumors. The minor salivary gland are spread throughout the mouth and throat, so the nature of the surgery will depend the location. Tumors of the front of the mouth (e.g. cheek, palate) can usually be removed through the mouth. Tumors in the back of the tongue or throat can sometimes be removed with laser or robotic surgery done through the mouth. Other tumors might require opening the jawbone to reach the back of the throat.
Should lymph nodes be removed in salivary gland cancer surgery?
Neck dissection involves removing some of the fat of the neck which contains lymph nodes, while protecting important structures like nerves and blood vessels. The nerves that move the tongue, shoulder, corner of the mouth are often found and protected while removing the lymph nodes around them. There are many lymph nodes in the neck, and only the nodes most likely to contain cancer cells are removed. Neck dissection is usually recommended for patients with high stage and/or high-grade tumors.
What is the role of reconstructive surgery after parotidectomy?
During the initial parotid surgery, tissue will be removed to treat the cancer which can cause structures to become damaged. Reconstruction surgery involves 1) repairing or replacing nerves which may have been cut or removed during surgery or 2) replacing the “lost tissue” with either new tissue or other materials.
What is the role of replacing tissue volume loss after surgery?
- Cosmesis– to fill in the space where tissue was removed for a better appearance
- Prevent Frey’s Syndrome (see above) – placing tissue between the skin and remaining parotid tissue reduces the chance of Frey’s
- Provide coverage of the facial nerve if radiation therapy is needed
- To allow for better facial nerve reconstruction
What are some options for replacing tissue loss after surgery?
Some options include fat grafts, grafts obtained from human cadavers or animal skin, or tissue flaps from your own body. Your surgeon may utilize one or more of these techniques depending on the size and location of the tissue loss and their experience/expertise.
What is the role of radiation in the treatment of salivary gland tumors?
Most salivary gland tumors are treated with surgery first. If the tumor is a high grade or advanced cancer (meaning, there is a high risk for the tumor to come back) then radiation treatment may be recommended following surgery to reduce the risk of the tumor re-growing. If surgery cannot be performed, radiation treatment may be recommended as the primary treatment. Radiation treatments are given by a radiation oncologist and typically involve treatment 5 days a week for 6-7 weeks.
What are the types of radiation treatment?
The most common type of radiation is external beam radiation using photons (a light particle) to treat the cancer cells. There are other types of radiation including proton beam and neutron beam radiation therapy. Proton beam therapy may be indicated for certain types of salivary gland cancers depending on their location. Proton beam therapy is only available at certain hospitals throughout the United States. Neutron radiation therapy has been used to treat salivary gland tumors but has not been well studied and may be associated with more complications than the other types of radiation. Neutron radiation therapy is only available at a few centers in the United States.
What is the role of chemotherapy in the treatment of salivary gland tumors?
Most salivary gland cancers are treated with surgery first. If surgery cannot be performed or the cancer has certain high-risk features, chemotherapy may be recommended. This is usually given with radiation therapy to decrease the risk of the cancer recurring. Chemotherapy alone may be used if the salivary gland cancer has spread to other parts of the body such as the lung, liver, or bones to try to slow down the growth and further spread of the cancer. The type and dose of chemotherapy is determined by a medical oncologist.
What is the role of immunotherapy in the treatment of salivary gland tumors?
Immunotherapy is a new type of treatment that helps your immune system fight off cancer cells. It is typically used for cancers that cannot be removed with a surgery or cancers that have spread to other parts of the body such as the lung, liver, or bones. The type and dose of immunotherapy is determined by a medical oncologist. Sometimes the cancer is tested for certain genetic changes that can be targeted with immunotherapy. The side effects of immunotherapy are typically easier to tolerate than the side effects of chemotherapy for most people.
What are possible side-effects of treatment for salivary cancer?
- Facial numbness
- Scar/ Skin changes/facial neck contour
- Shoulder Function
- Facial Nerve Function (facial weakness)
- Lingual Nerve Function (tongue numbness)
- Lymphedema (swelling of tissues)
- Loss of taste/saliva
- Difficulty with speech and swallowing
Are there clinical trials available for salivary cancer?
Trial links to NCI: www.clinicaltrials.gov
Why should I consider participating in a clinical trial?
Participating in a clinical trial may give you access to new treatments that are not otherwise available to most patients. You will also be helping to improve medical knowledge to help future patients with this disease.
Are there any types of alternative treatment for salivary gland tumors?
There is no evidence to support the use of herbal medications or dietary supplements (vitamins, minerals, etc) for the treatment of salivary gland tumors. Please discuss with your doctor before taking any of these medications as it can interfere with your treatment.
What follow up is needed after treatment for a salivary gland cancer?
After surgery to remove a cancer from the salivary glands, there will be regular follow up visits with the surgeon to monitor for signs of the cancer regrowing for at least 5 years. If radiation or chemotherapy was also used to treat the cancer, regular follow up visits will also be needed with these doctors. Depending on the type and location of the cancer, imaging studies such as ultrasound, CT scans, MRIs, or PET scans may be used to monitor for cancer recurrence.
What is the structure and function of the salivary glands?
- Anatomy – The parotid gland is the largest of the major salivary glands found in front and under the ear where it wraps around the back edge of the lower jawbone, known as the mandible. The gland is divided by the facial nerve (controls the movement of all the facial muscles on one side of the face) into a superficial (outer) lobe and a deep (inner lobe) of the gland. The anatomy of the parotid gland is very similar in structure to the anatomy of a tree. It has a main duct (like a tree trunk), which opens into the mouth on the inside of the cheek up near the upper molar teeth. This main duct extends back deep through the cheek tissue over the jawbone to the gland, and then branches into multiple smaller ducts, like a tree branching into limbs, branches, and twigs. All of the smaller ducts are surrounded by many smaller saliva producing cells (like the leaves on a tree) and these cells make the saliva which then empties into these small ducts and eventually out into the mouth through the main duct.
- Function – this gland makes a watery solution, which is mostly triggered by eating. The smell/taste of food sends a signal through the nervous system which stimulates (“turns on”) the gland to make a large amount of saliva to help wet moisten and digest food.
- Anatomy – The submandibular gland can be felt as a soft egg-sized lump under the lower jawbone midway along the side of the jawbone. Like the parotid gland, the submandibular gland is also divided by the mylohyoid muscle (a muscle which attaches to the lower jaw bone) into a superficial (felt in the neck) and deep component (felt under the tongue in the floor of mouth (the space between the tongue and the jaw bone). Like the parotid gland, the submandibular gland is structured like a tree. However, the duct which drains the submandibular gland starts in the neck component of the gland, heads backwards and then takes a sharp turn around the mylohyoid muscle to run forward under the surface of the floor of the mouth to where the duct empties, which is just under the front of the tongue through a bump in the floor of the mouth called a papilla. Unlike a tree the trunk or duct of the submandibular gland is wider where it branches in the gland (called the hilum) and narrower at the base (papilla) where it empties into the mouth. The big turn in the duct, its high viscosity saliva and the fact it gets smaller towards the ends can put the gland at risk for blockages, such as stone, which can block saliva flow and causing gland swelling. The nerve that gives feeling to the tongue also supplies nerve fibers to this gland which stimulate this gland to make saliva.
- Function – This gland makes a slightly more thickened saliva. It is thought that while the parotid gland mainly makes saliva in response to food, the submandibular gland is constantly making saliva to help keep the mouth wet and protect the teeth. However, this gland also can be “turned on” by the nervous system, like the parotid gland, through the lingual nerve.
- Anatomy – this gland lives under the floor of the mouth in the front of the mouth and connects to both the submandibular duct but also directly to the floor of mouth with small channels or pores (similar to how skin sweat glands connect to the skin surface). It is the smallest of the major salivary glands.
- Function – this gland makes a much thicker saliva, and much less amount than the other salivary glands.
- Minor Salivary Glands- Tongue, Palate, Pharynx, Larynx, Sinonasal, Ear Canal
- Minor salivary glands are individual glands without the complex “tree-like” anatomy of the major salivary glands. These glands produce a lubrication (oily-type) solution which helps to keep the nose and mouth moist/wet. These glands connect directly to the surface tissue of the mouth, known as mucosa, through small channel/pores
What are the options for facial nerve reconstruction?
The facial nerve begins in the brainstem and runs through the temporal bone (bone on the side of your head where your ear attaches), and then exits out a hole in this bone below your ear, after which it runs forward in your face through the parotid gland. As it runs forward, the main nerve branches into multiple smaller branches to supply all the facial muscles from the forehead down to the neck.
Primary nerve repair. If the facial nerve is cut, either on purpose or accidentally, during surgery and there is enough length in both segments of the nerve remaining to allow both ends to be brought back together without pulling hard on the nerve ends, then a primary repair can be done. In this case, the nerve ends are sewn together with small suture material, basically connecting the “nerve cable” back together. However, unlike connecting an electrical cable, which works again right after connection, the nerve repair does not work like this. Even a successful nerve repair may take 12 months before activity to that muscle returns and even then, it may not be completely normal. This is because there are thousands of individual nerve fibers in each cable that go to unique muscles in the face and bringing the ends back together does not guarantee that the same two fiber ends are going to connect to each other.
Nerve Graft: If there is a gap in the nerve to far to allow primary repair, your surgeon can perform a nerve graft. A piece of nerve long enough to fill the gap can be removed from another area of the body and used to bridge the gap between to two cut ends of the facial nerve. These grafts are typically from sensory nerves from the neck, leg or arm. As with primary repair, the return of function may take up to a year and often will not be complete
Nerve Transfer: If after the initial surgery, the main facial nerve is removed (preventing primary repair or nerve grafting), but the end of the nerve still attached to the muscles (distal segment) is present, then a nerve transposition or transfer can be done. There are motor (control muscle movement) nerves near the facial nerve that control tongue and jaw motion. The free edge of the distal facial nerve segment can be attached to either in end-to-end or end-to-side fashion to part one of these other motor nerves.
Cross-face grafting: This technique is also used when primary nerve repair or nerve grafting are not possible, and often it will be done along with nerve transposition. In this technique, a long sensory nerve graft is borrowed from another part of the body (often the lower leg) and this graft is to connected to a facial nerve branch on the other side of the face. The graft nerve is then tunneled under the skin of the upper lip to the side of the facial paralysis and connected to the free end of the cut facial nerve or to a muscle flap to help power the reconstruction.
What are some options for replacing tissue loss after salivary gland surgery?
Allogenic grafts – these are tissue grafts obtain from cadaver human or animal skin. They can be used to fill the space made after tumor surgery. Some patients may have an allergic reaction to these materials, which can cause swelling, itching, redness or pain. Over time, as long-term scar formation sets in, these grafts can get smaller creating reduced tissue volume on the side of the face.
Fat graft – Your surgeon may choose to remove fat from another part of your body and use this to fill the space left after parotid surgery. As the fat is your own tissue, there is no risk of an allergic reaction, but the graft will also shrink and get smaller with time, on average losing at least 30% of its volume.
Local and regional flaps – Your surgeon may offer to reconstruct the area by moving tissue from the neck or scalp area into the parotid surgery space. As this tissue keeps its own independent blood supply, the tissue typically keeps it volume with time. If there is need for radiation therapy after surgery, this tissue is also able to give better coverage of the facial nerve. If skin needs to be removed as part of your surgery, skin can also be replaced with many local and regional flaps.
Free tissue transfer – Your surgeon may offer this option, especially if your surgery involves removal of a large amount of tissue or jawbone. Free tissue transfer involves removing tissue from a different part of your body along with an attached artery and vein. They can be used to reconstruct very complex defects. Due to the delicate nature of the surgery, the surgical case can last longer and require more close monitoring afterwards. Some free tissue transfers also provide nerve grafts to allow for facial nerve reconstruction.
What is the role of radiation in the treatment of salivary gland tumors?
Radiation therapy for salivary gland tumors can be classified into 2 categories.
- Primary treatment in patients that surgery cannot be performed or that choose not to have surgery
- Treatment following surgery (called adjuvant radiation)
The reason a patient may not be able to undergo surgery for excision of a salivary gland tumor may be related to medical comorbidities for which it is unsafe to go under general anesthesia for the surgery. Sometimes patients refuse surgery due to the potential risks or side effects from the surgery. Additionally, patients with salivary gland cancers that have distant metastases (spread to lungs, liver, bone, etc) may be offered primary radiation treatment to control the tumor.
Primary treatment with radiation is called definitive radiation therapy (RT). This often requires a higher dose of radiation than adjuvant radiation given after surgery. The dose typically ranges from 66 – 70 Gray (Gy) which is given over the course of 6-7 weeks, 5 days a week.
Adjuvant radiation (following surgery)
There are certain types of salivary gland cancers that are more aggressive and have a higher rate of recurrence. In these cases, radiation is recommended following surgery to decrease the chance of recurrent cancer.
The indications for radiation after surgery includes certain types of cancer, such as acinic cell carcinoma, high grade mucoepidermoid carcinoma, salivary ductal carcinoma, or carcinoma ex-pleomorphic. Tumors that are a more advanced stage (T3 or T4) are typically considered for radiation treatment as well. This includes tumors that are > 4 cm, tumors that have grown out of the salivary gland to involve the skin, muscle, jawbone, ear canal, or facial nerve. Cancers with close margins or a finding of perineural invasion (cancer invading small nerves) or lymphovascular invasion (cancer invading small vessels) are also considered for adjuvant radiation treatment. Spread of the cancer to lymph nodes in the neck may also be treated with radiation after surgery.
If surgery was unable to remove all the cancer and/or there were positive margins, adjuvant radiation with the addition of chemotherapy is typically recommended.
Ideally, radiation treatment should start within 6 weeks from the day of surgery. Often the dose of radiation is lower than that given for primary radiation and ranges from 50-66 Gy. This is also given 5 days a week over 5-7 weeks.
In rare circumstances, patients with benign tumors called a pleomorphic adenoma may be considered for radiation treatment. Radiation may be recommended if the entire tumor cannot be removed safely, or if the tumor grows back and cannot be removed with surgery.
If interested, use the links below to learn more about radiation treatment of salivary gland tumors.
What are the types of radiation treatment?
The typical particles used in radiation for salivary gland tumors are photons. Photon beams kill cancer cells by causing DNA damage that prevents further growth and division. This is the type of radiation treatment discussed above that is given 5 days a week for 5-7 weeks.
Proton beam radiation may be a good option for certain patients especially if there is tumor involvement near the skull base, the eye, or along cranial nerves. This may also be an option for patients with recurrent cancer that have already received traditional external beam radiation treatment with photons.
Neutrons have been used in the form of fast neutron therapy and may be a good option in some patients. Use of this type of radiation is extremely limited by cost and availability and is only available in a couple locations in the United States.
To learn more about the different types of radiation therapy, use the links below:
What are the side effects of radiation treatment for salivary gland tumors?
The most common side effects of radiation therapy include dry mouth, sores in the mouth and throat, difficulty swallowing, and sunburn like changes to the skin which can range from redness and tenderness to blistering and peeling of the skin. Other side effects include loss or altered sense of taste, hearing loss, fatigue, damage to the jaw/mandible bone, and damage to the teeth. If pre-existing dental problems exist, the radiation oncologist may require an evaluation by a dentist prior to starting radiation. If severe dental issues exist, dental extractions may be necessary prior to starting radiation.
Typically, the first couple weeks of radiation treatment are well tolerated with minimal side effects. After the first couple weeks of radiation the side effects begin and some can continue months after the completion of radiation.
At higher doses of radiation, the risk of damage to the jawbone is increased. Approximately 5% of people that have radiation therapy for salivary gland malignancies will go on to develop osteoradionecrosis of the jaw. Osteoradionecrosis is where part of the jawbone dies. This condition can range from being mild and asymptomatic to severe and painful requiring additional treatment. Treatment ranges from conservative management with good oral hygiene, oral medication, antibiotics, hyperbaric oxygen, or surgical removal of the necrotic part of the mandible and reconstruction.