This information is provided by SSCHRC to help you understand thymoma and thymic carcinoma and their management. It is written in a patient-friendly and medically accurate style.
Thymoma is a rare tumour that develops in the thymus, a small organ located in the chest, behind the breast bone and above the heart. The thymus is a vital part of the immune system, playing a crucial role in the development of immune cells called lymphocytes.
Thymoma arises when the epithelial cells (the cells forming the outer layer, or capsule) of the thymus undergo a cancerous change, beginning to grow and divide rapidly. While the tumour originates from these epithelial cells, it may also contain a mixture of lymphocytes.
Thymomas are broadly categorised into three main types based on how the cells appear under a microscope:
This subtype involves cancerous spindle-shaped epithelial cells. The tumour may contain few or many lymphocytes, depending on the specific cancer. The prognosis for Type A thymoma patients is generally very good.
There are several sub-types of Type B thymoma, each with a different microscopic appearance. The prognosis for this type is variable.
This is the most aggressive form of the disease. The cells appear highly abnormal under a microscope, and the cancer has a high rate of metastasis (spreading) to other parts of the body. It is often diagnosed when the disease has already spread.
Because the thymus is part of the immune system, thymoma can sometimes trigger autoimmune diseases, where the body's immune system mistakenly attacks healthy cells.
This is the most common autoimmune disease associated with thymoma, causing muscle weakness, especially in the face, head, and neck. If MG is caused by the thymoma, successful treatment of the cancer can often resolve the MG.
Few known risk factors exist for thymoma, and it has not been definitively linked to family history or specific lifestyle behaviours. The main factors associated with the disease are:
Thymoma symptoms vary greatly among individuals, and many patients experience no symptoms at all, particularly in the early stages. Symptoms can be caused by the associated autoimmune disease, Myasthenia Gravis, or by the tumour pressing on nearby organs and structures, such as major blood vessels.
Important Note: It is important to note that these symptoms can also be signs of other health problems. Any persistent or concerning symptoms should be discussed with a doctor.
An accurate and early diagnosis is crucial for successful thymoma treatment. The experts at SSCHRC use advanced equipment and have extensive experience in accurately diagnosing all types of thymoma.
Often, thymoma does not present with symptoms in the early stages, and many cases are discovered incidentally, such as during a chest X-ray performed for an unrelated condition.
X-rays, Magnetic Resonance Imaging (MRIs), and CT scans are used to create detailed pictures of the chest. In many cases, doctors can make a strong diagnosis of thymoma based on imaging alone, without the need for a tissue sample.
This procedure involves obtaining a small tissue sample from the suspected tumour, which is then studied under a microscope by pathologists. The biopsy is often performed by a radiologist using image guidance (live image) to precisely guide a needle to the tumour site. Occasionally, an open biopsy requiring surgery may be necessary.
While blood tests cannot directly diagnose thymoma, they are valuable in helping doctors understand a patient's symptoms, especially in checking for autoimmune conditions like myasthenia gravis.
Cancer staging describes the size of the primary tumour and how far the cancer has spread within the body. Staging is vital for the care team to develop an appropriate treatment plan and estimate the patient's prognosis.
The TNM staging system is commonly used for many cancers and is based on three main factors:
Cancer is confined solely within the thymus and is entirely surrounded by the organ's capsule.
Cancer has spread through the capsule and into the surrounding fat or the lining of the chest cavity.
Cancer has spread to nearby organs in the chest, such as the lung, the sac around the heart (pericardium), or large blood vessels connected to the heart.
This advanced stage is divided into:
Successful thymoma treatment requires an experienced care team. Given that only a few hundred cases are diagnosed annually, the disease is rare for most physicians. However, the doctors at SSCHRC are members of a top-ranked cancer centre and treat a substantial number of thymoma patients each year, providing them with deep skill and expertise for newly diagnosed, metastatic, or recurrent disease.
Our doctors collaborate in multidisciplinary teams to discuss each patient's unique case. They coordinate a comprehensive, tailored treatment plan that may combine surgery, radiation therapy, and cancer drugs. SSCHRC also offers clinical trials for new treatment options, including targeted therapy and immunotherapy, for patients at all stages.
For thymomas smaller than four centimetres, surgical removal of the entire thymus, known as a thymectomy, is the standard approach.
This treatment uses drugs to kill rapidly dividing cells, including cancer cells. It can be used before surgery (neoadjuvant) to shrink the tumour or in combination with radiation therapy if surgery is not an option.
Patients with larger tumours are often given chemotherapy before surgery to shrink the tumour, which increases the likelihood of a successful surgical procedure.
This uses powerful energy beams to destroy cancer cells. It is typically given after surgery, or in combination with chemotherapy if surgery is not feasible. Treatment options include:
If the tumour has spread beyond the primary site, patients may receive a combination of radiation therapy and cancer drugs (like chemotherapy). Surgery may still be performed at the primary and distant sites to help relieve symptoms and improve patient outcomes, in coordination with other therapies.
Thymic Carcinoma (Type C): As this is typically diagnosed at an advanced stage, patients are treated with chemotherapy, radiation therapy, and potentially surgery.