Thymus cancer, also known as thymoma, is a rare type of cancer that originates in the thymus gland. The thymus gland is a small gland located behind the breastbone (sternum) and plays an important role in the development of the immune system.
Thymus cancer occurs when abnormal cells in the thymus gland grow and divide uncontrollably, forming a mass or tumor. Thymus cancer can be classified as either benign (non-cancerous) or malignant (cancerous), with malignant thymus cancer being more common.
Types of Thymus Cancer
Thymus cancer, also known as thymoma, is classified into several types based on the appearance of the cancer cells under a microscope. The World Health Organization (WHO) classification system divides thymomas into five types –
- Type A – This is the least aggressive form of thymoma and is characterized by a relatively uniform population of thymic cells.
- Type AB – This type of thymoma is a mixture of Type A and B cells and is considered to be an intermediate stage.
Type B1 – This type of thymoma contains a high number of lymphocytes and is typically slow-growing.
Type B2 – This type of thymoma contains a mixture of lymphocytes and more atypical thymic cells.
5. Type B3 – This is the most aggressive form of thymoma and contains a large number of atypical thymic cells.
In addition to these types of thymomas, there is a rare and aggressive form of thymus cancer known as thymic carcinoma. Thymic carcinoma arises from the epithelial cells of the thymus gland and is often associated with a poor prognosis. It is important to note that the treatment and prognosis of thymus cancer can vary widely based on the type and stage of cancer, as well as other factors such as the patient’s age and overall health status.
Causes and Risk Factors
The exact causes of thymus cancer, also known as thymoma, are unknown. However, there are several risk factors that have been associated with an increased risk of developing thymus cancer, including –
- Age – Thymus cancer is more commonly diagnosed in people over the age of 40.
- Gender – Thymus cancer is more common in men than in women.
- Autoimmune diseases – People with certain autoimmune diseases, such as myasthenia gravis, are at a higher risk of developing thymus cancer.
- Genetics – In rare cases, thymus cancer may be caused by inherited genetic mutations.
- Exposure to radiation – Exposure to radiation, such as radiation therapy for other cancers, may increase the risk of developing thymus cancer.
Having one or more risk factors does not necessarily mean that an individual will develop thymus cancer, and many people with thymus cancer have no known risk factors.
Thymus cancer, also known as thymoma, may not cause any symptoms in its early stages, and the symptoms that do develop can vary depending on the size and location of the tumor. Some common symptoms of thymus cancer include –
- Chest pain or discomfort
- Coughing or difficulty breathing
- Shortness of breath
- Difficulty swallowing
- Swelling in the neck or face
- Fatigue or weakness
- Fever or night sweats
- Unexplained weight loss
- Muscle weakness
These symptoms may be caused by conditions other than thymus cancer, but anyone experiencing these symptoms should consult a healthcare provider for an evaluation.
Diagnosis and Tests
Diagnosis of thymus cancer, also known as thymoma, typically involves a combination of imaging tests, such as chest X-rays, CT scans, and MRI scans, as well as a biopsy of the tumor tissue. Additional tests may also be performed to determine the extent of the cancer and whether it has spread to other parts of the body.
- Imaging tests – Chest X-rays, CT scans, and MRI scans are commonly used to detect the presence of a tumor in the thymus gland and to determine its size and location.
- Biopsy – A tissue sample from the tumor is obtained through a procedure known as a biopsy. This may be done through a needle biopsy, which involves inserting a thin needle through the skin and into the tumor, or a surgical biopsy, which involves removing a portion of the tumor tissue for examination.
- Blood tests – Blood tests may be performed to check for the presence of certain proteins or other markers that can indicate the presence of thymus cancer.
- Other tests – Depending on the extent of the cancer, additional tests may be performed to determine whether it has spread to other parts of the body, such as the lungs or lymph nodes. These may include PET scans, bone scans, or other imaging tests.
A team of specialists, including an oncologist, radiologist, and pathologist, will work together to review the test results and determine the stage and type of thymus cancer present. This information will guide the development of an individualized treatment plan for the patient.
Treatment for thymus cancer, also known as thymoma, typically involves a combination of surgery, radiation therapy, and/or chemotherapy. The specific treatment approach depends on several factors, including the stage of cancer, the size and location of the tumor, and the patient’s overall health.
1. Surgery – Surgery is one of the main treatments for thymus cancer, particularly for early-stage tumors that have not spread beyond the thymus gland. The goal of surgery is to remove as much of the tumor as possible while preserving nearby organs and tissues.
There are several types of surgery that may be used to treat thymus cancer, depending on the size and location of the tumor –
- Thymectomy – This is the most common type of surgery for thymus cancer. It involves removing the thymus gland and any nearby tissue that may contain cancer cells. Thymectomy can be performed through an open incision or using minimally invasive techniques such as video-assisted thoracoscopic surgery (VATS) or robotic surgery.
- Extended thymectomy – In some cases, the surgeon may need to remove additional tissues or organs that are affected by cancer, such as part of the lung or the lining of the heart.
- Radical thymectomy – This is a more extensive form of surgery that involves removing the thymus gland and all the tissue in the chest where the cancer may have spread. Radical thymectomy is typically reserved for advanced cases of thymus cancer.
After surgery, patients may need to stay in the hospital for several days or weeks, depending on the extent of the surgery and their overall health. They may also need follow-up treatment such as chemotherapy or radiation therapy to help prevent the cancer from returning.
2. Radiation therapy – Radiation therapy may be used in combination with surgery or as the primary treatment for thymus cancer that cannot be removed with surgery. Radiation therapy uses high-energy beams of radiation to destroy cancer cells.
3. Chemotherapy – Chemotherapy may be used in combination with radiation therapy or as the primary treatment for advanced or metastatic thymus cancer. Chemotherapy uses drugs to kill cancer cells.
4. Immunotherapy – Immunotherapy is a newer treatment approach that uses drugs to stimulate the immune system to attack cancer cells. This approach may be used in some cases of advanced thymus cancer.
The specific treatment approach for thymus cancer will depend on the individual case and may involve a combination of these treatment options. Patients with thymus cancer should work closely with their healthcare team to determine the best treatment plan for their specific case.
The outlook, or prognosis, for thymus cancer, depends on various factors, including the stage of the cancer, the size and location of the tumor, the age and overall health of the patient, and the treatment options available.
Overall, thymus cancer is a relatively rare type of cancer, and the outlook can vary widely depending on the individual case. In general, thymus cancer tends to grow slowly and may not cause symptoms for many years. However, in some cases, thymus cancer can be aggressive and can spread to other parts of the body, making it more difficult to treat.
The survival rates are based on population averages and may not accurately predict the outcome for an individual patient. Factors such as age, overall health, and response to treatment can also affect the outlook for thymus cancer. Patients with thymus cancer should work closely with their healthcare team to determine the best treatment plan and to monitor the progress of the disease.