What is Salivary Gland Cancer?
Abnormal cell growths that begin in the salivary glands are referred to as salivary gland cancer. This rare type of cancer starts in the glands responsible for producing saliva, which helps with digestion and keeps the mouth moist.
The salivary glands are located under and behind the jaw, in areas such as the parotid, sublingual, and submandibular glands. Additionally, small salivary glands are found in the lips, cheeks, mouth, and throat.
Salivary gland tumors can begin in any of these glands. They are usually benign, but malignant tumors can also occur, in which case it is called salivary gland cancer. Salivary gland cancer is particularly found in the parotid glands.
What are the Salivary Glands?
The salivary glands are located in the mouth and neck. They are responsible for producing saliva, which helps the digestive system begin to break down food.
Salivary Gland Cancer Diagnostic Criteria
The tests and procedures used to diagnose salivary gland cancer include:
Physical Examination
Specialists check for swelling in the jaw, neck, and throat to determine if further tests are needed.
Imaging Tests
Imaging tests such as magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), ultrasound, or X-rays can be used to determine the size and location of salivary gland tumors.
Biopsy
Fine needle aspiration or core needle biopsy can be used to collect tissue samples. A fine needle is inserted into the salivary gland to take a sample of the suspicious cells, which is then examined in a laboratory.
Causes of Salivary Gland Cancer
Salivary gland tumors are rare, and their exact causes are not known. Like other types of cancer, they result from uncontrolled cell growth due to DNA changes. However, the factors causing these DNA changes have not yet been identified.
Symptoms of Salivary Gland Cancer
Symptoms of salivary gland tumors include:
- Swelling in or near the jaw, neck, or mouth
- Numbness in part of the face
- Weakness in facial muscles
- Persistent pain in the salivary gland area
- Difficulty swallowing
- Trouble opening the mouth
Risk Factors for Salivary Gland Cancer
Factors that can increase the risk of developing salivary gland cancer include:
- Although salivary gland cancer can occur at any age, it is more commonly seen in older adults.
- Radiation treatments for head and neck cancer can increase the risk of developing salivary gland tumors.
- People who work with certain substances, such as those in rubber manufacturing, asbestos mining, and plumbing, have an increased risk of developing salivary gland tumors.
Treatment Methods for Salivary Gland Cancer
The primary treatment for salivary gland cancer is surgical removal of the tumor. Additional treatments such as radiation therapy and chemotherapy may also be applied.
Salivary Gland Cancer Surgery
Various surgical methods are used in salivary gland cancer surgery. The most suitable method for the patient is determined based on the type, stage of cancer, and the patient's overall health.
Surgical Methods for Salivary Gland Cancer
The surgical methods used in salivary gland cancer include:
Partial Removal of the Gland
If the tumor is small and accessible, surgeons can remove the tumor and a small margin of healthy tissue around it, allowing the remaining part of the salivary gland to continue functioning.
Total Removal of the Gland
If the tumor is large, it may be necessary to remove the entire salivary gland. If the tumor has spread to nearby structures such as facial nerves, ducts connecting the salivary glands, facial bones, or skin, the entire gland must be removed.
Removal of Neck Lymph Nodes
If the salivary gland tumor is cancerous and there is a risk of cancer spreading to the lymph nodes, specialists may recommend removing some lymph nodes in the neck, particularly those most likely to contain cancerous cells.
Reconstructive Surgery
This type of surgery is not intended to remove the tumor but to repair the area after the tumor removal surgery. If bones, skin, or nerves were removed during surgery, reconstructive surgery is needed to restore chewing, swallowing, speaking, breathing, and facial movement abilities.
Benefits of Salivary Gland Cancer Surgery
The primary phase of treating salivary gland cancer is surgery. In most cases, cancer cells can be completely removed surgically, allowing patients to recover with a short treatment period. If cancer cells cannot be completely removed, surgery helps shorten the duration of chemotherapy and radiotherapy.
Complications of Salivary Gland Cancer Surgery
The complications that can occur after salivary gland cancer surgery vary depending on the location and type of surgery performed.
Complications of Parotid Surgery
Complications that may occur after parotid surgery include:
- Bleeding
- Swelling
- Allergic reactions
- Infection
- Temporary or permanent damage to facial nerves
- Numbness in the earlobe
Complications of Submandibular Gland Surgery
Complications that may occur after submandibular gland surgery include:
- Bleeding
- Infection
- Restricted movement of the tongue
- Damage to facial nerves
- Facial asymmetry
- Swelling
- Complications related to anesthesia
- Allergic reactions
Radiation Therapy for Salivary Gland Cancer
Radiation therapy may be recommended for salivary gland cancer. This treatment uses high-energy beams such as X-rays and protons to kill cancer cells. During this treatment, the patient lies on a table while a machine moves around them, directing high-energy beams to specific areas of the body.
A relatively new type of radiation therapy that uses particles called neutrons has shown to be more effective in treating certain salivary gland cancers. However, more studies are needed to understand the benefits and risks of this treatment, so it is not commonly used.
Radiation therapy is used after surgery to kill any remaining cancer cells. It may also be recommended when the tumor is too large or its removal is too risky.
Chemotherapy for Salivary Gland Cancer
Chemotherapy, a treatment that uses drugs to kill cancer cells, is not a standard treatment for salivary gland cancer. However, specialists continue to study its use for salivary gland cancer. In rare cases, it is used in combination with radiation therapy.
Immunotherapy
Immunotherapy is a treatment option that uses various drugs to help the immune system identify and fight cancer cells. It is particularly used to combat metastatic cancer.
Targeted Therapy
Targeted therapy involves using drugs that target specific weaknesses in the genetic code of cancer cells to destroy or stop their growth. It is particularly applied to individuals with metastatic adenoid cystic carcinoma.
Radiosensitizers
Radiosensitizers are drugs used to make cancer cells more sensitive to radiation. This enhances the effectiveness of radiation therapy in treating salivary gland cancer.
Life After Salivary Gland Cancer
After salivary gland surgery, patients need to stay in the hospital for a few days to monitor for any complications and manage pain.
Patients are advised to wait at least a week before taking a shower. During the recovery period, it is important to maintain a comfortable room temperature to avoid getting too cold or sweating.
Stages of Salivary Gland Cancer
Salivary gland cancer is divided into different stages based on its spread. Defining the stages is the first step in planning treatment.
Stage 1
In the first stage of salivary gland cancer, the cancer cells have not spread to the lymph nodes. Noninvasive tumors are present, and there is no distant metastasis.
Stage 2
In the second stage of salivary gland cancer, there is still no distant metastasis or lymph node involvement. However, the tumor becomes invasive.
Stage 3
In the third stage of salivary gland cancer, there is regional lymph node involvement, but no distant metastasis. The tumors are small in this stage.
Stage 4
The fourth stage of salivary gland cancer is divided into three sub-stages. In stage 4a, there may or may not be lymph node involvement on the same side, and the tumors are invasive but without distant metastasis. Stage 4b includes more extensive lymph node involvement but no distant metastasis. In the final stage, 4c, distant metastasis is present.
Types of Salivary Gland Tumors
There are many different types of salivary gland tumors, classified based on the type of cells involved. Identifying the type of salivary gland tumor is crucial for planning treatment.
Benign Tumors
Non-cancerous tumors are referred to as benign salivary gland tumors and include the following subtypes:
- Pleomorphic adenoma
- Basal cell adenoma
- Canalicular adenoma
- Oncocytoma
- Warthin tumor
Malignant Tumors
Cancerous tumors are referred to as malignant salivary gland tumors and include the following subtypes:
- Acinic cell carcinoma
- Adenocarcinoma
- Adenoid cystic carcinoma
- Clear cell carcinoma
- Malignant mixed tumor
- Mucoepidermoid carcinoma
- Oncocytic carcinoma
- Polymorphous low-grade adenocarcinoma
- Salivary duct carcinoma
- Squamous cell carcinoma
