Salivary Gland Cancer

21.03.2024

DIAGNOSIS AND TREATMENT OF SALIVARY GLAND TUMOR

Salivary gland tumors are rare tumors that arise from the salivary glands and can be both benign and malignant. There are three pairs of large salivary glands in the human body: parotid glands (under the ear), submandibular glands (under the chin) and sublingual glands (under the tongue), as well as numerous smaller salivary glands. Most salivary gland tumors develop in the parotid glands and are mostly benign. Malignant tumors tend to develop in the deeper parts of the salivary glands and can be aggressive. Symptoms usually include swelling or mass in the salivary glands, pain, facial numbness or weakness, and rarely difficulty swallowing or speaking. Treatment of these tumors usually requires surgical intervention, and in malignant tumors, radiotherapy and chemotherapy may also be included in the treatment. Early diagnosis and appropriate treatment of salivary gland tumors are important for a good prognosis and functional results. Therefore, it is important to seek medical evaluation when abnormal growth or change in the salivary glands is noticed

WHAT ARE THE RISK FACTORS?

Although the exact causes of salivary gland tumors are not fully understood, some risk factors may play a role in the development of these tumors. These risk factors include:

Radiation Exposure: The risk of salivary gland tumor may increase in people who have received radiation therapy, especially to the head and neck area. This may be caused by receiving radiation during previous cancer treatments.

Aging: Salivary gland tumors are generally more common in middle-aged and older adults, but they can occur at any age.

Smoking: The use of cigarettes and other tobacco products may be a risk factor, especially for some types of salivary gland cancers.

Occupational Exposures: Working in certain jobs, such as working in industries such as asbestos, lead and nickel processing, may increase the risk of salivary gland tumors.

Genetic Factors: People with a family history of salivary gland tumors may have a slightly higher risk of developing such tumors, but this is rare.

Certain Viral Infections: Some studies have suggested that certain viruses, such as Epstein-Barr virus (EBV), may be associated with salivary gland tumors, but this relationship is not clear.

Because salivary gland tumors are rare, these risk factors may not explain the development of the tumors. However, being aware of these risk factors and regular health checks can help in the early diagnosis of possible tumors.

Image 1: Salivary gland diagnosis is made by biopsy taken from the mass.

HOW DOES IT OCCUR?

The mechanisms of development of salivary gland tumors are complex and not fully understood, but a combination of genetic and environmental factors play a role. Mutations in the DNA of cells in the salivary glands can lead to abnormal and uncontrolled growth of these cells, resulting in the formation of benign or malignant tumors. Radiation exposure can lead to DNA damage and ultimately mutations, especially in people who have had radiotherapy for head and neck cancers in the past. Additionally, it is thought that certain viral infections (e.g., Epstein-Barr virus) and exposure to environmental toxins (e.g., some industrial chemicals) may trigger genetic changes in salivary gland cells. Genetic predisposition may also be a factor in some cases. All these interactions lead to disruption of the normal growth and division cycles of cells in the salivary glands and the development of tumors. This process is the subject of ongoing research aimed at better understanding the molecular and cellular basis of salivary gland tumors.

WHAT ARE THE SYMPTOMS?

Signs and symptoms of salivary gland tumors may vary depending on factors such as the location, size and nature of the tumor (benign or malignant). These types of tumors usually begin as slow-growing masses and may present with the following symptoms:

Mass or Swelling: A palpable mass or swelling in the salivary glands, especially under the ear (parotid gland) or under the chin (submandibular gland). These are the most common symptoms of salivary gland tumors.

Pain: Pain may be felt as the tumor grows or puts pressure on the nerves.

Facial Numbness or Weakness: Malignant tumors can damage facial nerves, causing symptoms such as facial numbness, weakness, or paralysis.

Difficulty Swallowing or Speaking: When the tumor grows in the sublingual gland under the tongue or in other places, difficulty swallowing or speaking may occur.

Ear Pain or Pressure: Tumors, especially in the parotid gland, can press on the ear area, causing pain or pressure.

Irregular Growth: Tumors may grow rapidly or irregularly in size.

Changes in the Skin: The effects of the tumor on the skin may cause changes in the skin, such as discoloration or ulceration.

The presence of any of these symptoms may indicate the presence of a salivary gland tumor, but these symptoms may also be associated with other health conditions. Therefore, it is important to get a medical evaluation if such symptoms are present. Early diagnosis can increase the success of treatment of salivary gland tumors and lead to better health outcomes.

HOW IS IT DIAGNOSED?

The diagnosis of salivary gland tumors is made by a combination of clinical examination and various diagnostic tests. The process usually begins with an evaluation of the patient's symptoms and medical history. During the physical examination performed by an ear, nose and throat (ENT) specialist, abnormal masses or swellings in the salivary glands are looked for. If necessary, imaging tests may be performed for a more detailed evaluation; these include ultrasonography, computed tomography (CT), or magnetic resonance imaging (MRI). These tests help determine the size and location of the tumor and whether it has spread to surrounding tissues. Definitive diagnosis is usually made by biopsy; Here, a small tissue sample is removed from the tumor and examined under a microscope. Pathology examination helps determine whether the tumor is benign or malignant, as well as the type of tumor. This detailed diagnostic process is critical in determining an effective treatment plan and can impact the patient's prognosis and treatment options.

WHAT ARE THE PATHOLOGICAL TYPES?

Salivary gland tumors can have various pathological types. Some common types of pathology that can occur in the salivary glands include:

Pleomorphic adenoma: This is the most common benign tumor of the salivary glands. It may cause slight swelling.

Warthin tumor: It is a benign tumor usually found in the parotid salivary gland. It is more common in smokers.

Mucoepidermoid carcinoma: This is a common type of malignant tumor in the salivary glands.

Adenoid cystic carcinoma: It is a rare type of malignant tumor seen in the salivary glands.

Clear cell carcinoma: This type of cancer is another type of malignant tumor found in the salivary glands.

These are just some examples, and there may be more types and subtypes of tumors in the salivary glands. The nature of the tumor and treatment options may vary depending on the results of the pathological examination and the patient's medical history. If you have concerns or symptoms, it is important to consult a physician. Various receptors and immunohistochemistry markers can be used for pathological diagnosis of salivary gland tumors. These markers can help determine what type of cell structure the tumor has and whether the cancer is malignant. For example, some receptors used in the pathological examination of tumors in the salivary glands may be: p63 (for mucoepidermoid carcinoma), CK7 and CK19 (to determine the origin of the tumor), Ki-67 (to evaluate cellular proliferation). These receptors and markers are used to support accurate diagnosis of tumors in the salivary glands and the development of more effective treatment plans. Pathological examinations are important to determine the type and stage of the tumor and help determine treatment options.

Image 2: Salivary gland tumors may be confused with salivary gland inflammation.

HOW IS TUMOR STAGING DONE?

Staging of salivary gland tumors is a method used to determine the size, extent and other areas of the tumor. This staging process helps determine the correct treatment approach and prognosis of the tumor. Staging of salivary gland tumors is usually based on the following factors:

Tumor Size (T): It is examined how large the tumor is. T0 means that the tumor is not detected, while T1, T2, T3 and T4 represent increasing degrees of tumor size.

Lymph Node Involvement (N): The involvement of the lymph nodes around the tumor is examined. While N0 indicates the absence of lymph node involvement, N1, N2 and N3 indicate the presence and extent of lymph node involvement.

Distant Metastases (M): It is checked whether the tumor has spread to other parts of the body. While M0 indicates the absence of distant metastases, M1 indicates the presence of distant metastases.

A combination of these factors is used to determine the stage of the tumor. For example, "T2N0M0" indicates that the tumor is of medium size (T2), there is no spread to lymph nodes (N0), and there are no distant metastases (M0). Staging is important in determining the patient's treatment plan and prognosis and is performed by oncologists. The stage of the tumor helps determine appropriate treatment options.

HOW IS TREATMENT DONE ACCORDING TO STAGES?

The treatment approach for salivary gland tumors may vary depending on the stage and type of the tumor and the general health status of the patient. Treatment may often include a combination of methods such as surgery, radiation therapy, and chemotherapy. General treatment approach for salivary gland tumors according to stages:

Stage I and II Tumors: These tumors are usually small in size and locally confined. Treatment is usually done surgically. The aim is to remove the tumor and nearby healthy tissues. Post-surgical radiation therapy or sometimes surgery alone may be sufficient.

Stage III Tumors: At this stage, the tumor may become larger and spread to nearby lymph nodes. Treatment may require surgical removal and removal of lymph nodes (lymph node dissection). Radiation therapy may be considered after surgery.

Stage IV Tumors: In these stages, the risk of the tumor spreading to lymph nodes and other body parts is higher. Treatment may often include surgical removal, lymph node dissection, radiation therapy, and chemotherapy. In advanced stage tumors, treatment can often be more aggressive and a multidisciplinary approach may be required.

Every patient is different and the treatment plan should be determined individually. Oncologists recommend the most appropriate treatment by evaluating the stage, type, and other health factors of the patient's tumor. Post-treatment patient follow-up and rehabilitation are also important. Therefore, collaboration with an oncologist and a multidisciplinary healthcare team is important in the treatment of salivary gland tumors.

Image 3: Head and neck surgery, radiation oncology and medical oncology specialists are involved in the treatment of salivary gland tumors.

WHAT ARE THE DRUGS USED IN TREATMENT?

Chemotherapy, hormonal drugs, smart drug treatments and immunotherapies used in the treatment of salivary gland tumors may include:

Chemotherapy drugs:

Platinum-based chemotherapies: Can be used especially in the treatment of sialadenoid carcinoma and some other types of tumors.

5-Fluorouracil (5-FU): Can be used in the treatment of some salivary gland tumors.

Paclitaxel and Docetaxel: Chemotherapy agents administered intravenously may help control tumor growth.

Smart Drug Therapies:

Smart drug treatments can be used especially for tumors with some specific genetic mutations. For example, drugs such as trastuzumab or lapatinib can be used against HER2-positive salivary gland tumors.

Immunotherapies:

Immunotherapy drugs such as pembrolizumab and nivolumab can be used to treat salivary gland tumors by encouraging the immune system to attack cancer cells. These drugs may be particularly effective in PD-L1 positive tumors.

Treatment options may vary depending on the patient's tumor type, stage, genetic characteristics and health status. Therefore, the treatment plan should be determined individually by an oncologist and the healthcare team. Considering the patient's specific situation, the most appropriate treatment options are evaluated.

HOW SHOULD FOLLOW-UP BE DONE AFTER RECOVERY?

Follow-up after salivary gland tumor treatment aims to closely monitor the patient's health and helps detect early tumor recurrence or progression. Post-recovery follow-up may include the following elements: regular physical exams, imaging studies (for example, computed tomography or magnetic resonance imaging), blood tests, and medical interviews. Monitoring may be frequent for the first few years and then the intervals may increase over time. Each patient's follow-up plan is customized based on the tumor type, stage, and response to treatment. Monitoring the patient's symptoms, assessing his or her health status, and quickly intervening in treatment when necessary are among the main purposes of post-recovery follow-up. This process is an important step towards supporting the patient's long-term health and quality of life.