Salivary Gland Tumors
Salivary gland tumors are relatively uncommon compared to other tumors and account for less than 2% of all human tumors. Salivary gland tumors correspond to approximately 3% to 10% of neoplasms of the head and neck region.
Salivary gland cancer, a type of head and neck cancer, in which cancer cells form in the tissues of the salivary glands. Most salivary gland tumors are not life-threatening and are called benign tumors. Some benign tumors can become malignant over time.
Most Salivary Gland Cancers are found in the parotid glands. The parotid glands contain glands of the immune system (lymph nodes).
Types of Salivary Gland Tumors:
Types of salivary gland (parotid) tumors include:
- Mucoepidermoid Carcinoma: These are the most common salivary gland cancer type. Most of them begin in the parotid glands and don’t develop as often in minor salivary glands in the mouth or the submandibular glands.
- Adenoid Cystic Carcinoma: This is often slow-growing and is low-grade. But it is still extremely difficult to eliminate it since it often spreads along nerves. Also, these often come back following treatment (generally radiation and surgery), in some cases many years later.
- Adenocarcinomas: This is a term doctors use for describing cancers that begin in gland cells (these are cells that usually secrete some type of substance). There are various types of adenocarcinomas.
- Acinic cell carcinoma: Many of these begin in the parotid gland. They’re usually slow-growing and often develop at a younger age than many other types of salivary gland cancers. They’re typically low grade but predicting a patient’s outlook is better determined by how far they’ve grown into neighboring tissue.
- Polymorphous low-grade adenocarcinoma (PLGA): PLGA tumors often begin in the minor salivary glands. PLGA tumors often grow slowly and can usually be cured.
- Adenocarcinoma, not otherwise specified (NOS): NOS tumors, when observed under a microscope, have enough elements to be diagnosed as adenocarcinomas, however, not enough to further classify them. They’re most common in the minor salivary glands and parotid glands and can be any grade.
- Rare adenocarcinomas: Various forms of adenocarcinoma are very rare.
The causes of salivary gland tumors are not clear, it is known that they occur when some cells of a salivary gland have mutations in their DNA.
Factors that may increase the risk of salivary gland tumors include:
- Older age:It most commonly occur in older adults.
- Radiation exposure:Radiation used to treat head and neck cancers, increases the risk of salivary gland tumors.
- Workplace exposure to certain substances: such as rubber manufacturing, asbestos mining, and plumbing.
- Gender: Salivary gland cancers are more common in men.
- Poor nutrition poor nutrition may also be a risk factor for malignant salivary gland tumors.
Signs & Symptoms
Signs and symptoms of a salivary gland tumor may include:
- A lump or swelling on or near your jaw or in your neck or mouth
- Facial drooping numbness in part of your face
- Muscle weakness on one side of your face
- Persistent pain in the area of a salivary gland
- Difficulty swallowing
- Trouble in opening mouth widely
- Sore or swelling in the mouth
- Face, neck, and mouth pain
- Mouth bleeding
A doctor may use a variety of diagnostic tests to confirm the presence of a salivary gland tumor and to determine if the growth is malignant, including a complete medical history and physical exam, biopsy, and imaging tests.
The test includes:
- Medical history: This includes symptoms and signs you may have noticed, any other health conditions, medications that you are taking, and whether you smoke or drink alcohol.
- Physical examination: This includes examination of your mouth, face, jaw, ears and neck and a look for additional symptoms.
- Biopsy: This test helps your doctor check the cells of a growth or tumor for signs of cancer under a microscope. To complete the biopsy, your doctor will remove fluid or tissue from the area. This sample is then sent to a lab for testing and analysis.
- Imaging test: Special x-rays may be done. These include CT scans, MRIs, or Panorex. A Panorex is an x-ray that shows the full upper and lower jaw, including the jaw and sinuses. These imaging tests provide more details about the tissue. If cancer is found, the scans can show how deep the cancer is and if it has spread.
- Computed tomography CT scan: A CT scan can be used to measure the tumor’s size or to see if a tumor involves nearby bone.
- Magnetic resonance imaging (MRI): This uses magnetic fields to take pictures of the inside of the body. MRI is very good at looking at the salivary glands and determining whether any cancer is spreading along the nerves.
- PET-CT scan: This is a whole-body scan that uses a radioactive form of sugar that can show if salivary gland cancer has spread to other parts of the body. Low-grade salivary gland cancer may not show up on PET scans, because it tends to grow slowly.
- Ultrasound: An ultrasound uses sound waves to create a picture of the internal organs.
After determining a diagnosis and completing a pre-treatment, doctors will recommend a course of treatment for their patients. In general, there are three different options for the treatment of salivary gland cancers, that can be used alone or in combination.
- Surgery:For salivary gland cancer, complete surgical removal of the tumor is almost always the first treatment, unless a doctor decides that it is not possible or safe to proceed with surgery. Salivary gland cancers may be treated with a parotidectomy or a submandibular gland resection.
- Radiation Therapy:This treatment uses high-energy X-rays or particles to narrowly target and destroy cancer cells. This may either be the primary treatment, or it may be used with another treatment option.
- Chemotherapy:Chemotherapy is not usually effective in treating salivary gland cancers but may, in rare cases, be used if cancer has spread to other parts of the body outside of the head and neck. Chemotherapy may also be used in combination with radiation therapy in some instances.