Salivary gland cancer is a
type of cancer that can occur in any of the glands located on the face which
produce saliva. These include the parotid glands, submandibular glands and
sublingual glands. Parotid glands are the largest glands and account for 70
percent of all cancers of salivary gland cancer. Sub-mandibular glands are
found in the back of the jaw and are the origin for 20 percent of salivary
gland cancers. Finally, sublingual glands are rarely the starting point of
cancer. There are also hundreds of other smaller salivary glands that line
parts of the lips, tongue and inside of the cheek. Tumors in these small glands
are extremely rare, and when they do occur, they are usually malignant.
Benign Salivary Gland Tumors:
Most tumors that occur in salivary glands are benign or non-cancerous. They do not spread to other parts of the body and they are rarely life threatening. There are several different forms of benign salivary gland tumors, including adenomas, oncocytomas, Warthin tumor, and pleomorphic adenoma, a type of mixed benign tumor. When a patient has a benign salivary gland tumor, he or she usually has surgery performed to remove it. This is important because in some instances, a benign tumor may become cancerous.
Malignant Salivary Gland Tumors:
There are many different types of salivary gland cancers which are classified depending on the shape and structure of the cells when viewed under a microscope. To help doctors understand the seriousness of the cancer itself, they usually classify it into one of three different categories called grades. These grades help determine how fast the cancer will grow and spread in a patient's body.
Grade 1 salivary cancers are defined as having a well-differentiated structure because they have a structure that is similar to normal glandular cells found in the salivary glands. They grow very slowly and generally have a positive prognosis for patients who are diagnosed with this type of cancer.
Grader 2 salivary cancers are in the mid-range in terms of growth speed. They are considered to be moderately differentiated from normal cells and carry a prognosis between grade 1 and grade 3 salivary cancers.
Grade 3 salivary cancers are high grade and are considered to be poorly differentiated. When viewed under a microscope, grade 3 cancer cells look very different from normal cells. Their growth rate is very fast and can easily spread to other parts of the body. The prognosis for grade 3 cancers is generally poor.
Types of Salivary Gland Cancers:
A biopsy is used to help a doctor determine which type of salivary gland cancer a patient has. Since different types of cells are found within these glands, the type of cancer found can be one of the following possible types:
There are also more types of salivary gland cancer, though they are extremely rare:
· Squamous Cell Carcinoma
· Epithelial-Myoepithelial Carcinoma
· Anaplastic Small Cell Carcinoma
· Undifferentiated Carcinomas
· Non-Hodgkin Lymphoma
Doctors may sometimes have difficulty classifying a type of salivary gland cancer because the cells are very hard to distinguish from their physical properties. Malignant mixed tumors are types of malignant salivary gland cancers that fall within this spectrum. They include:
· Carcinoma ex pleomorphic adenoma
· Metastasizing mixed tumor
These indistinguishable cancers are often judged for treatment and prognosis by their grade.
Salivary Gland Cancer Causes:
A great amount of research has been done on DNA in salivary gland cells and how abnormalities in a cell's genes can lead to the development of cancer. Scientists believe that tumor suppression genes may become damaged, causing cells to divide uncontrollably. The main causes of cancer are exposure to radiation or what are known as carcinogens. Carcinogens are usually chemicals that have been known to alter DNA in cells, causing the development of cancer. Unfortunately, cancer forms mysteriously and much research is needed to understand exactly how DNA becomes damaged.
The exact cause of salivary gland cancer is still being researched by scientists and physicians. Fortunately, there are a number of risk factors that are known to aid in the development of cancer. Avoiding risk factors will ensure that one lives a normal, cancer-free life. Risk factors include:
A person may be exposed to radiation through a number of different means. This can include dangerous work environments, but can also come from radiation treatment a person receives to treat another type of cancer he or she may have.
Research suggests that a person may be more likely to develop cancer if they have a family history of cancer. This helps support evidence that a person's likelihood of developing cancer is carried in his or her genes.
Tobacco and Alcohol:
Tobacco, one of the most widely known carcinogens, and alcohol can contribute to the development of cancer.
A healthy diet rich in vegetables and low in animal fat will help prevent a person from developing cancer of any kind.
A great deal of research is being done on cell phones and their link to cancer, especially salivary gland cancer.
Prevention of Salivary Gland Cancer:
Salivary gland cancer prevention focuses heavily on avoiding the risk factors as described above. This includes eating a healthy diet, avoiding common carcinogens such as alcohol and tobacco, and avoiding all other hazardous materials that have been linked with the development of cancer. Certain substances that should be avoided are silica dust, nickel alloy dust and radioactive substances.
Salivary Gland Cancer Symptoms:
Salivary gland cancer is generally rare and begins in the face and neck area of a person where the salivary glands are located. Fortunately, salivary gland cancer has very noticeable symptoms that aid a patient in discovering it relatively early. The most common symptoms is an abnormal swelling on the side of face and neck area, which may form into a lump in the neck and throat area. Other symptoms include:
· Facial Palsy (droopiness of the face)
· Difficulty swallowing
· Trouble moving jaw
People who experience the symptoms above are encouraged to talk to a doctor immediately. While the symptoms he or she are experiencing could be caused by another condition, it is best to be sure.
Diagnosis of Salivary Cancer:
After a patient sees a doctor when experiencing symptoms of salivary gland cancer, there are several tests a doctor will perform. Seeing a doctor will include a physical exam as well as an examination of the mouth and neck areas of the patient. After the findings of the examine are determined, the doctor may order further tests to be done. The two main ways a doctor will test for salivary gland cancer are through special imaging tests and biopsies.
The simplest and most common form of imaging test is an x ray. Salivary gland cancer is one of the few cancers that can easily be seen through a common x ray. The x ray can help show the presence of any abnormalities found in the jaw and upper neck areas.
There are three common advanced imaging tests that may need to be performed as well to create a more detailed image of a persons face and neck area. The first is a CT scan, an imaging test that produces more powerful x rays to create cross sectional images of a patient's face and neck. This can be used to create a detailed image of the size, shape and exact position of a possible tumor. Next, an MRI test gathers a detailed image through the use of radio waves. MRIs can tell a doctor if a tumor is benign or malignant. Finally, a PET scan uses a special camera that picks up radioactivity absorbed by a patient's body prior to the test.
The biopsy helps a doctor determine for sure if a tumor is benign, malignant, or if a tumor is even present within a patient. It can help doctors find pre-cancerous conditions as well so that cancer can be prevented and/or closely monitored. It involves taking a sample of cells within the salivary glands of a patient. There are several methods used to perform a biopsy on a patient. This includes fine needle aspirations, incisional biopsies and surgery. The method used by a doctor usually depends on a patient's health and whether or not the first attempt of performing a biopsy is successful. Fine needle aspiration biopsies are the easiest to perform and are the least invasive, however, the sample they produce may not be enough to make a final decision.
The Staging of Salivary Cancer:
Like most cancers, salivary cancer is staged through the TNM system created by the American Joint Committee on Cancer. The reason for a doctor to stage a patient's cancer is to determine how advanced the tumor is so that a prognosis can be formed along with a course of treatment. For example, if a cancer is determined to be in stage II, surgery may be an elected course of treatment along with a follow-up treatment of radiation therapy.
In order for a cancer to be staged, the cancer is measured in three different dimensions. First, the size of the tumor is determined (T). Next, the presence of cancer cells in nearby lymph nodes are measured (N). Lastly, the cancer is searched for in distant parts of the body to see if it has metastasized (M). The cancer is then put into one of four stages (I-IV) based on the results of these three tests.
Salivary Cancer Prognosis:
The prognosis a doctor formulates is an educated guess about the outcome of a case of salivary gland cancer. The prognosis may also help affect the treatment options that are available as well. One of the biggest determinants of the prognosis is the stage of the cancer. The higher the stage, the poorer the prognosis. The grade of the cancer is another large factor. The prognosis is usually measured in a five year survival rate. This determines the number of patients that survive for five years or longer after being diagnosed with salivary cancer.
Treatment of Salivary Cancer:
The treatment of salivary cancer is largely based on the stage of the cancer. After the stage is measured, a course of treatment, depending on what is available, will be selected by a doctor. Generally, surgery is the most used option, especially in early stages, though options become more limited in stage IV salivary gland cancer.
A treatment option available in stages I through III of salivary gland cancer, salivary gland surgery is designed to remove the tumor along with surrounding tissues which may contain cancerous cells. In addition, a doctor may remove the entire salivary gland from the patient, along with lymph nodes from the neck. Surgery is almost always followed up with radiation therapy as well to help kill remaining cancer cells that were left behind.
Radiation therapy in salivary cancer can either be used as a primary treatment or a secondary follow up treatment to surgery. When used as a primary treatment, it is sometimes combined with chemotherapy. A doctor elects this method usually if the cancer is in stage IV and surgery is not possible. When it is used after surgery, it is done to kill remaining cancer cells so that a tumor does not grow back. Research is currently being done to improve the accuracy of radiation therapy and to make it more efficient because it can come with some side effects.
Chemotherapy is generally not used often in treatment of salivary gland cancer, especially in earlier stages of the cancer. It may be used, however, in stage IV cancer when it has spread to other parts of the body and in conjunction radiation therapy to shrink the tumor and relieve symptoms for a patient. Chemotherapy targets cells in the body which divide rapidly. This includes cancer cells, though other normal healthy cells are destroyed as well, including cells that line the lips and hair follicles. As a result, chemotherapy comes with many side effects, including hair loss, mouth sores, weakness, nausea and vomiting.
Salivary Gland Cancer Research:
Though research for salivary cancer continues, it is difficult to perform because salivary cancer is a relatively rare form of cancer. Research continues in clinical trials for development of new treatments, though improvements to currently existing treatments is also being developed. Improvements to currently existing treatments include:
As surgery techniques and technologies improve, researchers have found that surgery done by head and neck doctors to remove cancer at the base of the skull is now possible. A few years ago, most doctors would not even attempt to perform this operation, but today, it is done often and is usually successful.
Radiation therapy research continues to find more advanced techniques to make it more accurate, protecting normal healthy cells are the tumor. This is done with precision machines and tumor mapping to ensure that only tumor cells are killed by the treatment.
More drugs are being developed and tested for salivary gland cancer. Also, combinations of currently existing drugs are being tested for added effectiveness.
As gene research has become more widespread, new forms of cancer treatment have taken shape. One promising treatment is targeted therapy, which was developed as researchers understood the changes that take place in cells that develop into cancer. Targeted therapy uses drugs specifically designed to affect these changes.