General Information About Thymoma and Thymic Carcinoma
Thymoma and thymic carcinoma are diseases in which malignant (cancer) cells form on the outside surface of the thymus.
The thymus, a small organ that lies in the upper chest under the breastbone, is part of the lymph system. It makes white blood cells, called lymphocytes, that protect the body against infections.
Anatomy of the thymus gland. The thymus gland is a small organ that lies in the upper chest under the breastbone. It makes white blood cells, called lymphocytes, which protect the body against infections.
There are different types of tumors of the thymus. Thymomas and thymic carcinomas are rare tumors of the cells that are on the outside surface of the thymus. The tumor cells in a thymoma look similar to the normal cells of the thymus, grow slowly, and rarely spread beyond the thymus. On the other hand, the tumor cells in a thymic carcinoma look very different from the normal cells of the thymus, grow more quickly, and have usually spread to other parts of the body when the cancer is found. Thymic carcinoma is more difficult to treat than thymoma.
For information on thymoma and thymic carcinoma in children, see the PDQ summary on Unusual Cancers of Childhood Treatment.
Thymoma is linked with myasthenia gravis and other autoimmune diseases.
People with thymoma often have autoimmune diseases as well. These diseases cause the immune system to attack healthy tissue and organs. They include:
- Myasthenia gravis.
- Acquired pure red cell aplasia.
- Hypogammaglobulinemia.
- Polymyositis.
- Lupus erythematosus.
- Rheumatoid arthritis.
- Thyroiditis.
- Sjögren syndrome.
Signs and symptoms of thymoma and thymic carcinoma include a cough and chest pain.
Thymoma and thymic carcinoma may not cause early signs or symptoms. The cancer may be found during a routine chest x-ray. Signs and symptoms may be caused by thymoma, thymic carcinoma, or other conditions. Check with your doctor if you have any of the following:
- A cough that doesn't go away.
- Chest pain.
- Trouble breathing.
Tests that examine the thymus are used to detect (find) thymoma or thymic carcinoma.
The following tests and procedures may be used:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
- Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the chest, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body, such as the chest. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
Thymoma and thymic carcinoma are usually diagnosed, staged, and treated during surgery.
A biopsy of the tumor is done to diagnose the disease. The biopsy may be done before or during surgery (a mediastinoscopy or mediastinotomy), using a thin needle to remove a sample of cells. This is called a fine-needle aspiration (FNA) biopsy. Sometimes a wide needle is used to remove a sample of cells and this is called a core biopsy. A pathologist will view the sample under a microscope to check for cancer. If thymoma or thymic carcinoma is diagnosed, the pathologist will determine the type of cancer cell in the tumor. There may be more than one type of cancer cell in a thymoma. The surgeon will decide if all or part of the tumor can be removed by surgery. In some cases, lymph nodes and other tissues may be removed as well.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options depend on the following:
- The stage of the cancer.
- The type of cancer cell.
- Whether the tumor can be removed completely by surgery.
- The patient's general health.
- Whether the cancer has just been diagnosed or has recurred (come back).
Stages of Thymoma and Thymic Carcinoma
Tests done to detect thymoma or thymic carcinoma are also used to stage the disease.
Staging is the process used to find out if cancer has spread from the thymus to other parts of the body. The findings made during surgery and the results of tests and procedures are used to determine the stage of the disease. It is important to know the stage in order to plan treatment.
There are three ways that cancer spreads in the body.
Cancer can spread through tissue, the lymph system, and the blood:
- Tissue. The cancer spreads from where it began by growing into nearby areas.
- Lymph system. The cancer spreads from where it began by getting into the lymph system. The cancer travels through the lymph vessels to other parts of the body.
- Blood. The cancer spreads from where it began by getting into the blood. The cancer travels through the blood vessels to other parts of the body.
Cancer may spread from where it began to other parts of the body.
When cancer spreads to another part of the body, it is called metastasis. Cancer cells break away from where they began (the primary tumor) and travel through the lymph system or blood.
- Lymph system. The cancer gets into the lymph system, travels through the lymph vessels, and forms a tumor (metastatic tumor) in another part of the body.
- Blood. The cancer gets into the blood, travels through the blood vessels, and forms a tumor (metastatic tumor) in another part of the body.
The metastatic tumor is the same type of cancer as the primary tumor. For example, if thymic carcinoma spreads to the bone, the cancer cells in the bone are actually thymic carcinoma cells. The disease is metastatic thymic carcinoma, not bone cancer.
The following stages are used for thymoma:
Stage I
In stage I, cancer is found only within the thymus. All cancer cells are inside the capsule (sac) that surrounds the thymus.
Stage II
In stage II, cancer has spread through the capsule and into the fat around the thymus or into the lining of the chest cavity.
Stage III
In stage III, cancer has spread to nearby organs in the chest, including the lung, the sac around the heart, or large blood vessels that carry blood to the heart.
Stage IV
Stage IV is divided into stage IVA and stage IVB, depending on where the cancer has spread.
- In stage IVA, cancer has spread widely around the lungs and heart.
- In stage IVB, cancer has spread to the blood or lymph system.
Thymic carcinomas have usually spread to other parts of the body when diagnosed.
The staging system used for thymomas is sometimes used for thymic carcinomas.
Recurrent Thymoma and Thymic Carcinoma
Recurrent thymoma and thymic carcinoma is cancer that has recurred (come back) after it has been treated. The cancer may come back in the thymus or in other parts of the body. Thymic carcinomas commonly recur. Thymomas may recur after a long time. There is also an increased risk of having another type of cancer after having a thymoma. For these reasons, lifelong follow-up is needed.
Treatment Option Overview
There are different types of treatment for patients with thymoma and thymic carcinoma.
Different types of treatments are available for patients with thymoma and thymic carcinoma. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
Four types of standard treatment are used:
Surgery
Surgery to remove the tumor is the most common treatment of thymoma.
Even if the doctor removes all the cancer that can be seen at the time of the surgery, some patients may be given radiation therapy after surgery to kill any cancer cells that are left. Treatment given after the surgery, to lower the risk that the cancer will come back, is called adjuvant therapy.
Radiation therapy
Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy:
- External radiation therapy uses a machine outside the body to send radiation toward the cancer.
- Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer.
The way the radiation therapy is given depends on the type and stage of the cancer being treated. External radiation therapy is used to treat thymoma and thymic carcinoma.
Chemotherapy
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.
Chemotherapy may be used to shrink the tumor before surgery or radiation therapy. This is called neoadjuvant chemotherapy.
Hormone therapy
Hormone therapy is a cancer treatment that removes hormones or blocks their action and stops cancer cells from growing. Hormones are substances produced by glands in the body and circulated in the bloodstream. Some hormones can cause certain cancers to grow. If tests show that the cancer cells have places where hormones can attach (receptors), drugs, surgery, or radiation therapy is used to reduce the production of hormones or block them from working.
Hormone therapy with drugs called corticosteroids may be used to treat thymoma or thymic carcinoma.
New types of treatment are being tested in clinical trials.
This summary section describes treatments that are being studied in clinical trials. It may not mention every new treatment being studied. Information about clinical trials is available from the NCI website.
Patients may want to think about taking part in a clinical trial.
For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.
Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.
Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.
Patients can enter clinical trials before, during, or after starting their cancer treatment.
Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.
Clinical trials are taking place in many parts of the country. See the Treatment Options section that follows for links to current treatment clinical trials. These have been retrieved from NCI's listing of clinical trials.
Follow-up tests may be needed.
Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests.
Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.
Treatment Options for Thymoma and Thymic Carcinoma
Stage I and Stage II Thymoma
Treatment of stage I thymoma is surgery.
Treatment of stage II thymoma is surgery followed by radiation therapy.
Check the list of NCI-supported cancer clinical trials that are now accepting patients with stage I thymoma and stage II thymoma. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. Talk with your doctor about clinical trials that may be right for you. General information about clinical trials is available from the NCI website.
Stage III and Stage IV Thymoma
Treatment of stage III and stage IV thymoma that may be completely removed by surgery includes the following:
- Surgery with or without radiation therapy.
- Neoadjuvant chemotherapy followed by surgery with or without radiation therapy.
- A clinical trial of anticancer drugs in new combinations or doses.
- A clinical trial of new ways of giving radiation therapy.
Treatment of stage III and stage IV thymoma that cannot be completely removed by surgery includes the following:
- Neoadjuvant chemotherapy followed by surgery and/or radiation therapy.
- Radiation therapy.
- Chemotherapy.
- A clinical trial of anticancer drugs in new combinations or doses.
- A clinical trial of new ways of giving radiation therapy.
Check the list of NCI-supported cancer clinical trials that are now accepting patients with stage III thymoma and stage IV thymoma. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. Talk with your doctor about clinical trials that may be right for you. General information about clinical trials is available from the NCI website.
Thymic Carcinoma
Treatment of thymic carcinoma that may be completely removed by surgery includes the following:
- Surgery with or without radiation therapy.
- A clinical trial of anticancer drugs in new combinations or doses.
- A clinical trial of new ways of giving radiation therapy.
Treatment of thymic carcinoma that cannot be completely removed by surgery includes the following:
- Radiation therapy.
- Chemotherapy with or without surgery to remove part of the tumor and/or radiation therapy.
- Chemotherapy with radiation therapy.
- Chemotherapy.
- A clinical trial of anticancer drugs in new combinations or doses.
- A clinical trial of new ways of giving radiation therapy.
Check the list of NCI-supported cancer clinical trials that are now accepting patients with thymic carcinoma. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. Talk with your doctor about clinical trials that may be right for you. General information about clinical trials is available from the NCI website.
Recurrent Thymoma and Thymic Carcinoma
Treatment of recurrent thymoma and thymic carcinoma may include the following:
- Surgery with or without radiation therapy.
- Radiation therapy.
- Hormone therapy.
- Chemotherapy.
- A clinical trial of anticancer drugs in new combinations or doses.
- A clinical trial of new ways of giving radiation therapy.
Check the list of NCI-supported cancer clinical trials that are now accepting patients with recurrent thymoma and thymic carcinoma. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. Talk with your doctor about clinical trials that may be right for you. General information about clinical trials is available from the NCI website.
To Learn More About Thymoma and Thymic Carcinoma
For more information from the National Cancer Institute about thymoma and thymic carcinoma, see the Thymoma and Thymic Carcinoma Home Page.
For general cancer information and other resources from the National Cancer Institute, see the following:
- About Cancer
- Staging
- Chemotherapy and You: Support for People With Cancer
- Radiation Therapy and You: Support for People With Cancer
- Coping with Cancer
- Questions to Ask Your Doctor about Cancer
- For Survivors and Caregivers
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PDQ® Adult Treatment Editorial Board. PDQ Thymoma and Thymic Carcinoma Treatment. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/types/thymoma/patient/thymoma-treatment-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389395]
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Last Revised: 2016-08-09
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