The thymus is a small organ located behind the breastbone and is part of the immune system. The thymus is larger and more active during childhood and gradually shrinks in adulthood.
Thoracic surgeons at UT Southwestern Medical Center provide state-of-the-art surgical techniques with a major focus on early diagnosis, better cancer staging, and multidisciplinary care to enhance the treatment of thymic malignancies. Our NCI-designated Comprehensive Cancer Center, the gold standard for cancer centers, is a center for excellence in patient care, research, and education, and is the only center with this designation in North Texas.
UT Southwestern’s team of expert surgeons, medical oncologists, and radiation oncologists develops a treatment strategy customized to each patient, based on such factors as the type of tumor, the stage of the disease, and the condition and overall health of the patient. It may include surgery, radiation therapy, and chemotherapy.
While our surgeons perform traditional open surgeries when needed, most operations are performed using the latest minimally invasive techniques, including robotic surgery to minimize pain and recovery time. We are one of the most experienced teams in the world in robotic surgery for thymoma and have published extensively in leading academic journals about our work.
Types of Thymic Tumors
Tumors of the thymus are rare and of three types:
Thymomas are the most common tumors of the thymus. These tumors begin in the cells in the cortex or outer portion of the thymus. Although thymomas tend to grow slowly and rarely spread outside the thymus, they are always cancerous, and if ignored or treated less aggressively, they can result in debility and often death.
Thymic carcinomas are less frequent and comprise one in ten thymic tumors. Thymic carcinomas can grow more quickly than thymomas and can spread outside the thymus. These tumors more often appear in older people and require combinations of different therapies, including chemotherapy, radiation, and surgery.
Thymic carcinoid tumors are rare and slow-growing tumors, also known as neuroendocrine tumors. Although they more commonly arise from the intestines and lungs, they can also originate from the thymus and are more likely to spread or recur than thymomas.
Many people do not experience symptoms from a thymic tumor and are found to have a tumor only as a result of a test for an unrelated condition. Thymomas may be associated with myasthenia gravis, an autoimmune neuromuscular disease that results in progressive weakness.
Surgical removal of the thymoma and medical therapy are necessary to treat this condition. On occasion, thymic carcinoid tumors can produce too much of a hormone called ACTH, which causes the adrenal glands to produce excess amounts of cortisol, leading to Cushing’s syndrome, a disease characterized by weight gain, muscle weakness, obesity, and hypertension. Removal of the tumor results in resolution of the symptoms.
Imaging tests can help us determine the size, location, and shape of the tumor as well as whether the tumor is invading neighboring structures.
Tests and imaging techniques used to make a diagnosis include:
- Biopsy (tissue sample) when needed, through a needle or an incision
- Blood work
- Chest X-rays (radiographs)
- Computed tomography (CT) scan
- Magnetic resonance imaging (MRI)
- Positron emission tomography (PET)
A small tissue sample or biopsy from the tumor is examined under a microscope. The tissue sample is either obtained with a small needle inserted into the chest, or through a small incision on one side of the breastbone.
People with small, early tumors (stage I) are candidates for surgical removal as the treatment of choice. People with large and more advanced thymic tumors that have spread to the tissues surrounding the thymus (stage II), or to neighboring organs (stage III), as well as tumors that have spread into the chest cavity (stage IV), or return after treatment often require a combination of treatments, including chemotherapy and radiation in addition to extensive surgery.
Surgical procedures include:
- Extrapleural pneumonectomy for recurrent or stage IV thymoma – through a large chest incision, the pleural lining of the inside of the chest wall, the lung, diaphragm, and covering of the heart are removed
- Minimally invasive or video-assisted thoracoscopic surgery (VATS) thymectomy – use of minimally invasive equipment to remove the thymus and the tumor
- Open thoracotomy, median sternotomy, transverse sternotomy – through a large incision, the tumor, the thymus, and all of the anterior mediastinal soft tissue surrounding major chest structures are removed
- Pleural metastatectomy for recurrent thymoma – either through VATS or robotic technique, the disease is removed
- Pleural decortication – through a large chest incision, the pleural lining of the chest wall and the lining covering the lung and diaphragm are completely removed
- Robotic thymectomy – use of a robot to remove the thymus and the tumor
Minimally Invasive Surgery
Compared to surgery performed through an open incision, minimally invasive surgery provides several important benefits for patients, including
- Faster recovery and return to normal activities
- Less pain
- Little scarring
- Minimal blood loss
- No cutting of the ribs or sternum
- Possible improved cure rates for cancer
- Shorter hospital stay
UT Southwestern conducts clinical trials aimed at improving the treatment of thymoma and thymic cancer. Talk with your doctor to see if a clinical trial may be right for you.