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Salivary Gland Disease
The major salivary glands produce approximately one quart of saliva each day, which in turn plays a crucial role in food digestion, swallowing, speech, and protection of teeth against bacteria and decay. Obstruction or blockage of the salivary glands is relatively common, affecting up to 2% of the population. Salivary gland obstruction results in pain and swelling in the cheek or under the jawline while eating, and foul-tasting drainage into the mouth. Such obstruction can also progress to severe infection associated with high fevers, pain, and progressive swelling.
Common CausesSalivary gland blockage can result from multiple causes including salivary stones, narrowing of the duct by scar tissue, dehydration, side-effects of certain medications, autoimmune diseases and tumors. Radioiodine treatment, often used in the treatment of thyroid cancer, is also associated with salivary gland obstruction due to concentration of radioiodine within the gland parenchyma.
The most common cause of salivary obstruction in adults is salivary stones. Approximately 90% of stones occur in the submandibular glands, with the other 10% occuring in the parotid glands. The sublingual glands are rarely affected. Salivary stones generally form when mucous sludge combines with calcium hydroxylapatite and deposits within the salivary ducts. While some stones can be seen with simple X-rays or CT scans, approximately 60% are invisible to x-rays and require other tests, such as ultrasonography, for accurate detection.
TreatmentsTraditional treatments of salivary gland obstruction have focused largely on temporary relieving symptoms, rather than identifying and eliminating the source of the problem. Increasing fluid intake, sucking on sour candies or lemons, applying warm compresses, and massaging the swollen gland are common recommendations.
When these recommendations fail to provide relief, it has been common to undergo major surgery to remove the affected gland. While often done successfully and without complications, such surgeries are not without risks of bleeding, infection, and damage to surrounding nerves.
The UAB Department of Otolaryngology is one of the few institutions in the US to offer minimally-invasive procedures for the diagnosis and treatment of salivary gland obstruction. Sialendoscopy is a technique that has been developed and successfully applied in Europe over the last decade, but only recently has been introduced in the United States. This procedure can be performed under general anesthesia, sedation, or local anesthesia and is typically performed as an outpatient procedure. The technique uses semi-rigid, ultra-thin scopes that are inserted into the gland's natural opening in the mouth in order to visualize and diagnose the cause of the obstruction. Using specialized micro-instruments, stones and scar tissue can be removed in order to relieve the blockage. The scope can also cleanse the glands with an irrigation of saline solution and steroids.
Treatment For Salivary Gland Cancer
ChemotherapyIf you have a salivary gland tumor, your physician may recommend chemotherapy, or treatment with anti-cancer drugs. These medicines are distributed throughout the body through the bloodstream. They can help kill cancer cells that may have spread to other areas of the body, called metastases.
Physicians do not often use chemotherapy for salivary gland tumors because the drugs currently available do not cure the disease. But chemotherapy may help shrink the tumors in some cases, control tumors that surgery and radiation did not control, and treat metastases. New drugs are becoming available all the time, and future agents may be more effective in treating salivary gland cancers. Your doctor can talk with you about whether chemotherapy might be useful in your situation.
Fred Hutch patients who have salivary gland tumors receive chemotherapy at the South Lake Union clinic.
Radiation TherapySome people with salivary gland tumors receive radiation therapy as their main treatment or along with other treatments. If your tumor is too large to remove surgically or in a position that makes it hard to operate on, or if your health is poor and surgery may be risky, then your physician may suggest radiation as your main treatment.
Radiation therapy uses high-energy X-rays to kill cancer cells. People with salivary gland tumors receive external radiation therapy. A machine outside the body delivers a dose of radiation that travels through the outer structures, such as the skin, into deeper areas of the body. (For other types of cancer, radiation is sometimes given internally, through implanted radioactive "seeds" or other methods.)
Your physician may choose standard radiation or a type called neutron therapy that is more powerful than standard radiation and may be especially effective against salivary gland tumors. Fred Hutch is one of only three facilities in the United States that offers neutron therapy.
Salivary gland tumor patients at Fred Hutch receive radiation and neutron therapy at UW Medical Center - Montlake.
SurgeryMost people with salivary gland cancer have surgery to remove their tumor and part of the surrounding tissue. This tissue might include some healthy tissue from the affected gland or some bone or other soft tissue nearby. Some people have lymph nodes removed from their neck, too — either because a biopsy showed the cancer had spread there or because the cancer is high grade and likely to spread to these nodes.
The facial nerve, a major nerve that control muscles in the face, passes through the parotid gland. If you need surgery to remove cancer from this gland, our surgeons will use techniques to operate on the gland without damaging the nerve, if at all possible. In some cases, there is no way to remove the cancer effectively without removing part of the facial nerve. This can cause side effects, such as paralysis on that side of the face. This may be the best option for some patients. Sometimes physicians can use nerve-grafting procedures to help repair the nerve. To preserve the facial nerve, our physicians sometimes combine more limited surgery with neutron therapy, a powerful form of radiation.
If your cancer is in some other gland beside the parotid, other nerves might be affected by surgery. When you are considering surgery, ask your physician to explain all the risk and benefits, including how your nerves might be affected.
Salivary gland tumor patients at Fred Hutch have surgery at UW Medical Center - Montlake.
Neutron TherapyUW Medical Center is one of three facilities in the United States to offer neutron therapy, an especially powerful kind of radiation therapy shown to be effective against salivary gland tumors and some other forms of cancer. Fred Hutch is proud to offer this unique treatment to patients.
Each year our physicians use neutron therapy to treat about 100 people with cancer. About 80 percent of these patients have tumors of their major or minor salivary glands. They come from all around the country and the world.
"This is the best nonsurgical treatment available for salivary gland tumors," says George Laramore, MD, PhD, radiation oncology specialist. Laramore has treated patients with neutrons from all corners of the United States and as far away as Israel, Taiwan, Australia, and countries throughout Europe and South America.
"Because this is a rare tumor, there are not going to be very many neutron facilities in the country. We are very lucky that we have it here in the Northwest," says Laramore. "We probably see more salivary gland patients than anywhere else in the world."
Hope for Large or Inoperable Tumors
The University of Washington received a contract from the National Cancer Institute in the late 1970s to design and build a clinical neutron therapy facility and then participated in many research studies, called clinical trials, to determine when and how to use neutron therapy effectively. Physicians at the university started treating patients using neutrons at the CNTS in 1984.
The equipment for neutron therapy is about 10 times as expensive as the equipment for regular radiation therapy, and a neutron therapy facility has specific physical requirements. So it's unlikely more facilities of this kind will be built in the U.S. "A neutron radiotherapy facility would probably cost $20 million to $25 million dollars today," says Laramore, prohibitively expensive for most institutions, especially given the small number patients for whom this important therapy is useful.
When salivary gland tumors are detected early, the standard treatment is surgical resection, or removal. But when tumors are more advanced, there's a risk that surgery will mean sacrificing the facial nerve, leaving patients with facial paralysis. Our surgeons use surgical techniques designed to spare the facial nerve, explains Laramore. But this may mean leaving some of the tumor behind, he says. At this point, neutron therapy is added to their treatment plan.
"We use neutron therapy when there are high-risk features postoperatively or when surgery is not possible," says Laramore. He estimates that each year only about 500 patients in the country are diagnosed with salivary gland tumors considered large or inoperable.
Neutron therapy is especially good at controlling salivary gland cancer at the tumor site and in the same region. (Some patients still develop distant metastases, areas where the cancer spreads.) Neutron therapy also works best on tumors below 4 centimeters in diameter, controlling about 80 percent of tumors this size. But it is used with success on many larger tumors as well.
One of the early studies on neutron therapy for salivary gland cancer, started in the 1980s, was halted early because patients getting neutron therapy were doing so much better than others in the study. Researchers did not want to deprive the rest of the study subjects of the benefits of the neutron option.
Neutron therapy can be used to treat cancer in areas other than the salivary glands as well. For instance, at Fred Hutch, we sometimes use neutron therapy to treat cancer of the bones, joints, and soft tissues (sarcomas); certain radio-resistant tumors, such as melanomas, renal cell cancers and thyroid cancers; and other cancers — especially when surgery is not an option.
These are generally situations where the size and location of the tumor or the patient's general medical condition make it too difficult or risky to operate.
How Is Neutron Therapy Different?
Regular radiation therapy for cancer uses beams of electrons or photons (also called x-rays) to bombard cancer cells. The collisions release free radicals — unusually active atoms that have one or more unpaired electrons. Free radicals damage the DNA in the cancer cells, ideally killing them. Each dose kills only some of the targeted cells, depending on where the cells are in their life cycle. So physicians give multiple doses over time to reach more of the cells during the periods when they are most vulnerable.
Neutron therapy uses beams of neutrons to attack cancer cells. There are two advantages to using neutrons instead of electrons or photons. The first is that neutron beams are much more powerful. They deposit about 20 to 100 times as much energy into the target tissue as regular radiation therapy does.
The second is that neutron beams have a higher probability to damage both strands of a cell's DNA, whereas regular radiation in general damages only one strand. This makes it harder for cells to repair neutron beam damage and harder for them to survive the treatment. So neutron therapy is a good choice in some cases when tumors are resistant to regular radiation.
Because neutron beams are so damaging, the risk of side effects on healthy tissue near the cancer site is greater. For this reason and because neutron beams tend to diffuse more, neutron therapy equipment includes many mechanisms designed to precisely focus and direct the beam and to block exposure to any surrounding tissue.
What Happens During Treatment
Before a patient receives neutron therapy, his or her physician uses imaging techniques such as computed tomography (CT) scan, magnetic resonance imaging (MRI) and positron emission tomography (PET) scan to establish the exact location of the tumor and to decide exactly which spots to target with the neutron beam. Then the patient visits the neutron therapy facility for a treatment planning session. During this visit, a radiation oncology physician simulates the treatment, determining the best positions for the patient and the equipment and the appropriate dose of neutrons. This process is computerized.
"Our goal is to optimize the neutron beam to maximize damage to the tumor and minimize damage to any other tissue," says Laramore. It may take up to a week to develop an optimal treatment plan and actually begin treatment. For treatment, the patient lays on a padded table, also referred to as a couch. A pillar supports the table from underneath. The radiation therapist can move the table up and down, sideways and lengthwise, and can swing and rotate it to get the patient in exactly the right position for the neutron beam. Most patients receive beams from several different angles, usually two to four.
The neutron beam comes out of a large arm called a gantry. The gantry can rotate 360 degrees to deliver the beam from above or below the patient or from the side. To accommodate the large gantry arm, the floor can open as the gantry turns below the patient.
At the end of the gantry near the patient is a section called the treatment head, the part from which the beam emerges. Attached to the head is a leaf collimator. The "leaves" are narrow rectangular pieces of steel. There are 40 leaves inside the collimator. A computer controls the position of each leaf according to the radiation treatment plan. This creates an opening that's the right size and shape and in the right location for the patient's tumor. This opening is called the field. The radiation oncologist checks each field.
When the neutron beam reaches the collimator, the steel leaves block areas of the beam that would otherwise hit healthy tissue; the opening formed by the leaves allows part of the beam to get through to the patient. The whole rotating assembly, including the gantry, treatment head, collimator, and gantry counter weights, weighs about 39 tons.
An actual treatment session takes about 30 to 60 minutes, depending on how complicated the treatment delivery scheme is. Most of this time is spent getting the patient and equipment into the right positions. The time when the neutron beam is on lasts only about 1 to 2 minutes from each treatment angle. Typically patients get 16 to 18 treatments over a period of 4 to 5 weeks.
Sometimes patients find it tiring or uncomfortable to lie still for their treatment; otherwise there's no discomfort during the treatment when the beam is hitting the target area. The side effects from neutron therapy are similar to those from regular radiation therapy but may be more intense. They depend upon the area of the body that is being treated and may include:
Behind the Scenes
From the treatment room, the patient sees only the last few pieces of equipment involved in delivering their neutron beam. Behind the scenes — literally behind the wall that holds the gantry — are the many devices needed to generate the neutrons.
Here's what happens before the beam emerges from the collimator: The whole process begins with hydrogen gas. A device called an ion source strips electrons off the hydrogen atoms creating protons. The ion source is located at the center of a particle accelerator called a cyclotron. The cyclotron then uses magnetic and electrical fields to spin the protons in a spiral, accelerating them. The CNTS cyclotron can speed up protons to about 30 percent of the speed of light. In the linear accelerators used in regular radiation therapy, particles travel in a straight line, not a spiral. To get protons to as high a speed as the cyclotron can, a linear accelerator would have to be several tens of meters long. This wouldn't be practical in a treatment facility such as a hospital. The cyclotron is both more compact than a linear accelerator.
Once the protons reach the high energy level needed, they are guided out of the cyclotron into a beam line tube. The protons are guided down the beam line and through the gantry arm by multiple magnets which control the shape and direction of the proton beam. In the treatment head the protons strike a target made out of beryllium metal. The collision breaks apart some of the beryllium atoms, separating the neutrons (which are neutral — they have no electrical charge) from charged fragments. The charged fragments don't travel far, but the neutrons are penetrating. They escape from the area of the reaction and travel through the collimator opening to the tumor site. Unwanted neutrons are absorbed in the collimator leaves and other shielding devices.
Salivary Gland Cancer: Signs And Symptoms To Detect At An Early Stage
Salivary gland cancer, which targets the glands that generate saliva in the mouth, throat, and neck, is a relatively uncommon yet severe form of cancer. Recognizing the symptoms and signs of salivary gland cancer is crucial, as prompt detection and therapy can enhance survival rates. Salivary gland cancer affects the salivary glands, which are situated in the mouth, throat, and neck and produce saliva to aid digestion and maintain moisture in the mouth. Although this cancer can develop in any of these glands, it is most frequently seen in the parotid gland, situated in front of the ear.
The signs and symptoms of salivary gland cancer can be subtle, making it difficult to diagnose in its early stages. However, a lump or swelling in the jaw, ear or cheek, pain or numbness in the face, difficulty swallowing or opening the mouth, facial weakness, changes in taste or smell, dry mouth, difficulty speaking, ear pain, and facial swelling are all warning signs of this cancer.
While these symptoms can be caused by other conditions, it is important to rule out salivary gland cancer as a possible cause. If you experience any of these symptoms, it is important to see your doctor as soon as possible.
Risk Factors for Salivary Gland Cancer
While the exact cause of salivary gland cancer is unknown, there are several factors that may increase your risk of developing the disease. These include:
Early detection of salivary gland cancer is critical to effective treatment and recovery. If diagnosed in its early stages, the chances of survival are much higher than if diagnosed in later stages. This is why it is essential to be aware of the signs and symptoms of salivary gland cancer and to seek medical attention if you experience any of them.
While the topic of cancer can be scary and overwhelming, it is important to remember that early detection and treatment can make a significant difference in the outcome. As a society, we must prioritize regular medical check-ups and encourage those around us to do the same. By educating ourselves and those around us about the signs and symptoms of salivary gland cancer, we can help ensure that those who are at risk receive timely and effective treatment.
Additionally, we must also prioritize cancer research and funding. While salivary gland cancer is rare, it is no less important to find a cure for this and other forms of cancer. By investing in cancer research, we can improve our understanding of cancer and develop new treatments that can save lives. Finally, we must recognize the role that lifestyle choices can play in preventing cancer. While some risk factors for salivary gland cancer are beyond our control, there are many lifestyle choices we can make to reduce our risk of developing cancer. These include quitting smoking, reducing alcohol consumption, eating a healthy diet, exercising regularly, and protecting ourselves from the sun.
In conclusion, salivary gland cancer is a rare but serious form of cancer that can be difficult to diagnose in its early stages. It is important to be aware of the signs and symptoms of this cancer, so that we can seek medical attention if necessary. We must also prioritize cancer research and funding, and make lifestyle choices that reduce our risk of developing cancer. By working together, we can improve our understanding of cancer and save lives.
DisclaimerViews expressed above are the author's own.
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