Salivary Gland Cancer

Text-only Preview

Salivary Gland Cancer
What is cancer?
The body is made up of hundreds of millions of living cells. Normal body cells grow,
divide, and die in an orderly fashion. During the early years of a person's life, normal
cells divide faster to allow the person to grow. After the person becomes an adult, most
cells divide only to replace worn-out or dying cells or to repair injuries.
Cancer begins when cells in a part of the body start to grow out of control. There are
many kinds of cancer, but they all start because of out-of-control growth of abnormal
Cancer cell growth is different from normal cell growth. Instead of dying, cancer cells
continue to grow and form new, abnormal cells. Cancer cells can also invade (grow into)
other tissues, something that normal cells cannot do. Growing out of control and invading
other tissues are what makes a cell a cancer cell.
Cells become cancer cells because of damage to DNA. DNA is in every cell and directs
all its actions. In a normal cell, when DNA gets damaged the cell either repairs the
damage or the cell dies. In cancer cells, the damaged DNA is not repaired, but the cell
doesn't die like it should. Instead, this cell goes on making new cells that the body does
not need. These new cells will all have the same damaged DNA as the first cell does.
People can inherit damaged DNA, but most DNA damage is caused by mistakes that
happen while the normal cell is reproducing or by something in our environment.
Sometimes the cause of the DNA damage is something obvious, like cigarette smoking.
But often no clear cause is found.
In most cases the cancer cells form a tumor. Some cancers, like leukemia, rarely form
tumors. Instead, these cancer cells involve the blood and blood-forming organs and
circulate through other tissues where they grow.
Cancer cells often travel to other parts of the body, where they begin to grow and form
new tumors that replace normal tissue. This process is called metastasis. It happens when
the cancer cells get into the bloodstream or lymph vessels of our body.

No matter where a cancer may spread, it is always named for the place where it started.
For example, breast cancer that has spread to the liver is still called breast cancer, not
liver cancer. Likewise, prostate cancer that has spread to the bone is metastatic prostate
cancer, not bone cancer.
Different types of cancer can behave very differently. For example, lung cancer and
breast cancer are very different diseases. They grow at different rates and respond to
different treatments. That is why people with cancer need treatment that is aimed at their
particular kind of cancer.
Not all tumors are cancerous. Tumors that aren't cancer are called benign. Benign tumors
can cause problems -- they can grow very large and press on healthy organs and tissues.
But they cannot grow into (invade) other tissues. Because they can't invade, they also
can't spread to other parts of the body (metastasize). These tumors are almost never life
What is salivary gland cancer?
Salivary gland cancer is a cancer that starts in one of the salivary glands. It is not a single
disease. There are actually several different salivary glands found inside and near your
mouth. Several types of cancer and benign (non-cancerous) tumors can develop in these
About the salivary glands
Salivary glands produce saliva -- the lubricating fluid found in the mouth and throat.
Saliva contains enzymes that begin the process of digesting food. It also contains
antibodies and other substances that help prevent infections of the mouth and throat.
The 2 main types of salivary glands are the major salivary glands and minor salivary

There are 3 major salivary glands, which occur in pairs:
• The parotid glands, the largest salivary glands, are found on each side of the face,
just in front of the ears. About 7 out of 10 salivary gland tumors start here. Most of
these tumors are benign (non-cancerous), but the parotid gland is still where most
malignant (cancerous) salivary gland tumors start.
• The submandibular glands are smaller and are found at the back of the jaw. They
secrete saliva under the tongue area. About 1 or 2 out of 10 tumors start in these
glands, and about half of these tumors are benign.
• The sublingual glands, which are the smallest, are found under the floor of the
mouth and below either side of the tongue. Tumors starting in these glands are rare.
In addition, there are several hundred minor salivary glands that are too small to see
without a microscope. These glands are located beneath the lining of the lips, tongue,
hard and soft palate, and inside the cheeks, nose, sinuses, and larynx (voice box). Tumors
in these glands are uncommon, but they are more often malignant than benign.
Benign salivary gland tumors
Most salivary gland tumors are benign -- that is, they do not spread from the salivary
gland to other parts of the body and are almost never life threatening.
There are several types of benign salivary gland tumors, with names such as adenomas,
oncocytomas, Warthin tumors, and benign mixed tumors (also known as pleomorphic
Benign tumors are almost always cured by surgery. Very rarely, they may become
malignant (cancerous) if left untreated for a long time or if they are not completely
removed and recur (grow back) several times.

Only malignant tumors of the salivary glands will be discussed further in this document.
Salivary gland cancers (malignant salivary gland tumors)
There are many types of salivary gland cancers. Normal salivary glands are made up of
several different types of cells, and tumors can start in any of these cell types. Salivary
gland tumors are named according to which of these cell types they most look like when
viewed under a microscope. The main types of cancers are described below.
There is also a wide range in how quickly salivary gland cancers may grow and spread,
with some types tending to grow faster than others. Doctors usually give these cancers a
grade (from 1 to 3, or from low to high), based on how abnormal the cancers look under
a microscope. The grade gives a rough idea of how quickly the cancer is likely to grow
and spread.
Grade 1 cancers (also called low grade or well differentiated) look very much like
normal salivary gland cells. They tend to grow slowly and have a good outcome.
Grade 2 cancers (also called intermediate grade or moderately differentiated) have an
appearance and outlook that is between grade 1 and grade 3 cancers.
Grade 3 cancers (also called high grade or poorly differentiated) look quite different
from normal cells and often grow and/or spread quickly. The outlook (prognosis) for
these cancers is usually not as good as for lower grade cancers.
Mucoepidermoid carcinoma
Most mucoepidermoid carcinomas start in the parotid glands. They develop less often in
the submandibular glands or in minor salivary glands inside the mouth. These cancers are
usually low grade, but they can also be intermediate or high grade. Low-grade
mucoepidermoid tumors have a much better prognosis than high-grade ones.
Adenoid cystic carcinoma
Adenoid cystic carcinoma is the most common type of cancer in the minor salivary
glands. It is usually slow growing and often appears to be a low-grade tumor. It is very
hard to completely get rid of and often comes back after surgery, sometimes many years
later. The outlook for patients with low-grade adenoid cystic carcinoma is much better
than for high grade tumors of this type.
Adenocarcinoma is a term used to describe cancers that start in gland cells (cells that
normally secrete a substance). There are many types of salivary gland adenocarcinomas.
Acinic cell carcinoma: Most acinic cell carcinomas start in the parotid gland. They tend
to be slow growing. They are usually low grade, but how far they have grown into nearby
tissue is probably a better predictor of a patient's prognosis (outlook).

Polymorphous low-grade adenocarcinoma: These tend to start in the minor salivary
glands. These are usually low grade (as the name states) and are mostly curable.
Adenocarcinoma, not otherwise specified: When viewed under a microscope, these
cancers have enough features to tell that they are adenocarcinomas, but not enough detail
to classify them further. They are most common in the parotid glands and the minor
salivary glands. These tumors can be of any grade.
Rare adenocarcinomas: Several types of adenocarcinoma are quite rare. Many of these
tumor types tend to be low grade and usually have a very good outcome:
• Basal cell adenocarcinoma
• Clear cell carcinoma
• Cystadenocarcinoma
• Sebaceous adenocarcinoma
Mucinous adenocarcinoma
Other rare adenocarcinomas are more likely to be high grade and may have a less
favorable outcome:
• Oncocytic carcinoma
• Salivary duct carcinoma
Malignant mixed tumors
There are 3 types of malignant mixed tumors, carcinoma ex pleomorphic adenoma,
carcinosarcomas, and metastasizing mixed tumor. Carcinoma ex pleomorphic adenoma
accounts for the vast majority of these cancers. The other 2 are very, very rare.
Carcinoma ex pleomorphic adenoma is a cancer that develops from a benign mixed
tumor (also known as a pleomorphic adenoma). This tumor occurs mainly in the major
salivary glands. Both the grade of the cancer and how far it has spread (stage) are
important in predicting the outcome of this tumor.
Other rare salivary gland cancers
Several other cancer types can develop in the salivary glands.
Squamous cell carcinoma: This cancer occurs mainly in older men. It can develop after
radiation therapy for other cancers in the area. This type of cancer tends to have a poorer
Epithelial-myoepithelial carcinoma: This is a rare tumor. It tends to be low grade, but it
can come back after treatment or spread to other parts of the body.

Anaplastic small cell carcinoma: The cells in these tumors have nerve-like features.
These tumors are most often found in minor salivary glands and tend to grow quickly.
Undifferentiated carcinomas: This group of cancers includes small cell undifferentiated
carcinoma, large cell undifferentiated carcinoma and lymphoepithelial carcinoma. These
are high-grade cancers that often spread. Overall, the survival outlook tends to be poor.
Lymphoepithelial carcinoma, which is much more common in Eskimo and Inuit people,
has a slightly better outcome.
Non-Hodgkin lymphoma: Most non-Hodgkin lymphomas start in lymph nodes. Rarely,
hese cancers start in immune system cells within the salivary glands. They behave and
are treated differently than other types of cancer in the salivary glands. Most lymphomas
that start in the salivary glands affect people with Sjögren's syndrome (a disorder that
causes immune system to attack salivary gland cells). For more information on
lymphomas, see our document, Non-Hodgkin Lymphoma.
What are the key statistics about salivary
gland cancer?

Salivary gland cancers are not very common, accounting for less than 1% of cancers in
the United States. They occur at a yearly rate of about 2 cases per 100,000 people per
year in the United States.
They can occur at almost any age, but about 2 out of 3 salivary gland cancers are found in
people who are 55 or older. The average age at the time of diagnosis is 64.
Statistics related to survival are discussed in the section, “How is salivary gland cancer
What are the risk factors for salivary gland

A risk factor is anything that affects your chance of getting a disease such as cancer.
Different cancers have different risk factors. For example, exposing skin to strong
sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancers of the lung,
larynx (voice box), mouth, throat, esophagus (tube that carries food to the stomach),
kidneys, bladder, and several other organs.
But risk factors don't tell us everything. Having a risk factor, or even several risk factors,
does not mean that you will definitely get the disease. And many people who get the
disease may not have had any known risk factors. Even if a person has one or more risk
factors, it is not possible to know for sure how much that risk factor contributed to
causing the cancer.
Scientists have found few risk factors that make a person more likely to develop salivary
gland cancer.

Radiation exposure
Radiation treatment to the head and neck area for other medical reasons increases your
risk of salivary gland cancer. Workplace exposure to certain radioactive substances may
also increase the risk of salivary gland cancer.
Family history
Very rarely, members of some families seem to have a higher than usual risk of
developing salivary gland cancers.
Other possible risk factors
Certain workplace exposures
Some studies have suggested that working with certain metals (nickel alloy dust) or
minerals (silica dust) may increase the risk for salivary gland cancer, but these links are
not certain. The rarity of these cancers makes this a difficult area to study.
Tobacco and alcohol use
Tobacco and alcohol can increase the risk for several cancers of the head and neck area,
but they have not been strongly linked to salivary gland cancers in most studies.
Some studies have found that a diet low in vegetables and high in animal fat may increase
the risk of salivary gland cancer, but more research is needed to confirm this possible
Cell phones
One recent study suggested an increased risk of parotid gland tumors among heavy cell
phone users. In this study, most of the tumors seen were benign (not cancer). Other
studies looking at this issue have not found such a link. Research in this area is still in
progress. If there is any excess risk, it could be decreased by using corded or cordless
earpieces that move the device away from the user's head and decrease the amount of
radiation that reaches the body.
Do we know what causes salivary gland

We know very little about the actual causes of most salivary gland cancers. Researchers
have found that some salivary gland cancers have DNA abnormalities.

DNA is the chemical in each of our cells that makes up our genes -- the instructions for
how our cells function. We usually look like our parents because they are the source of
our DNA. However, DNA affects more than how we look. It also can influence our risk
for developing certain diseases, such as some kinds of cancer.
Some genes contain instructions for controlling when cells grow and divide. Genes that
promote cell division are called oncogenes. Genes that slow down cell division or cause
cells to die at the right time are called tumor suppressor genes. Cancers can be caused by
DNA changes that turn on oncogenes or turn off tumor suppressor genes.
Exposure to radiation or certain carcinogens (cancer-causing chemicals) may result in
these DNA changes, but in most cases of salivary gland cancer their cause is not known.
Can salivary gland cancer be prevented?
Because we do not know what causes most salivary gland cancers, it is not yet possible to
prevent them. Avoiding certain risk factors (tobacco, excessive alcohol use, unhealthy
diets) may slightly lower the likelihood of developing salivary gland cancer, although this
is not certain. However, avoiding these factors is known to reduce the risk of other, more
common cancers, as well as many other diseases.
People who work with radioactive substances, silica dust, and nickel alloy dust should
take precautions to protect themselves against exposure to these materials.
These precautions may lower a person's risk of developing salivary gland cancer.
Can salivary gland cancer be found early?
Salivary gland cancer is uncommon, so doctors do not recommend testing for it unless
someone has symptoms. Still, because of its location, in many cases salivary gland cancer
can be found early. Often patients or their doctors notice a mass or lump within one of the
salivary glands (usually on the sides of the face or in the mouth). Checking the salivary
glands for lumps is often a routine part of general medical and dental checkups.
Being alert to certain symptoms and not ignoring them might help find salivary gland
cancers early, when treatment is likely to be most effective.
How is salivary gland cancer diagnosed?
Salivary gland cancer is most often diagnosed when a patient goes to a doctor because of
Signs and symptoms of salivary gland cancer
The major salivary glands are located on the sides of the face and below the tongue.
Several important nerves and other structures run through or near salivary glands and can

be affected by salivary tumors. Possible signs and symptoms of salivary gland cancer
• A mass or lump in your face, neck, or mouth
• Ongoing pain in one place in your face, neck, or mouth
• A newly noticed difference between the size and/or shape of the left and right sides of
your face or neck
• Numbness in part of your face
• New weakness of the muscles on one side of your face
• Trouble swallowing
These are symptoms and signs of salivary gland cancer, but they may also be caused by
other conditions. Still, if you have any of these problems, it's important to see your doctor
right away so the cause can be found and treated, if needed.
Medical history and physical exam
If you have any signs or symptoms that suggest you might have a salivary gland tumor,
your doctor will want to take a complete medical history to check for symptoms and risk
factors, including your family history.
Medical history
The first step is to take your complete medical history, in which the doctor asks you
questions about risk factors and symptoms that might suggest salivary gland cancer. You
will also be asked about your general health.
Physical exam
A physical exam provides information about your general health, possible signs of
salivary gland cancer, and other health problems. During your physical exam, your doctor
will carefully examine your mouth and the areas on the sides of your face and around
your jaw, and will look for enlarged lymph nodes in your neck area since these could be
signs of cancer spread.
The doctor will also examine you for numbness or muscle weakness in part of your face
(which can happen when cancer spreads into nerves) and any other related problem that
you may be having.
If the results of this exam are abnormal, your doctor may order imaging tests or refer you
to an otolaryngologist (a doctor specializing in ear, nose, and throat problems).

Imaging tests
Imaging tests use x-rays, magnetic fields, sound waves, or radioactive particles to create
pictures of the inside of your body. Imaging tests may be done for a number of reasons,
including to help find a suspicious area that might be cancerous, to learn how far cancer
may have spread, and to help find out if treatment has been effective.
If you have a mass near the jaw, your doctor may order x-rays of the jaws and teeth to
look for a tumor.
If you have been diagnosed with cancer, an x-ray of your chest may be done to see if the
cancer has spread to your lungs. It also provides other information about your heart and
lungs that might be useful if surgery is planned.
Computed tomography (CT or CAT) scan
A CT scan is an x-ray procedure that produces detailed cross-sectional images of your
body. Instead of taking one x-ray, a CT scanner takes many pictures as it rotates around
you. A computer then combines these into images of slices of the part of your body that is
being studied. CT scans provide better detail about soft tissues than standard x-rays and
can often detect tumors.
Before any pictures are taken, you may be asked to drink 1 to 2 pints of a liquid called
oral contrast. This helps outline the intestine so that certain areas are not mistaken for
tumors. This is most often needed for CT scans of the abdomen or pelvis. You may also
receive an IV (intravenous) line through which a different kind of contrast dye (IV
contrast) is injected. This helps better outline structures in your body.
The injection can cause some flushing (redness and warm feeling). Some people are
allergic and get hives or, rarely, more serious reactions like trouble breathing and low
blood pressure. Be sure to tell the doctor if you have ever had a reaction to any contrast
material used for x-rays.
You need to lie still on a table while the scan is being done. During the test, the table
moves in and out of the scanner, a ring-shaped machine that completely surrounds the
table. You might feel a bit confined by the ring you have to lie in while the pictures are
being taken.
The CT scan can provide information about the size, shape, and position of a tumor and
can help find enlarged lymph nodes that might contain cancer. If needed, CT scans can
also be used to look for tumors in other parts of the body.
Magnetic resonance imaging (MRI)
Like CT scans, MRI scans provide detailed images of soft tissues in the body. But MRI
scans use radio waves and strong magnets instead of x-rays. The energy from the radio