Last Modified : 2008-02-05
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.
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.
Having a disease called myasthenia gravis can affect the risk of developing thymoma.People with thymoma often have other diseases as well. These diseases may include myasthenia gravis, polymyositis, lupus erythematosus, rheumatoid arthritis, thyroiditis, Sjögren syndrome, and hypogammaglobulinemia.
Possible signs of thymoma and thymic carcinoma include a cough and chest pain.Sometimes thymoma and thymic carcinoma do not cause symptoms. The cancer may be found during a routine chest x-ray. The following symptoms may be caused by thymoma, thymic carcinoma, or other conditions. A doctor should be consulted if any of the following problems occur:
The following tests and procedures may be used:
A biopsy of the tumor is done to diagnose the disease. The biopsy may be done before or during surgery, using a thin needle to remove a sample of cells. This is called a fine-needle aspiration (FNA) 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:
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.
The following stages are used for thymoma:In stage I, cancer is found only within the thymus. All cancer cells are inside the capsule (sac) that surrounds the thymus.
Invasive thymoma (stage II, stage III, and stage IV)Invasive thymoma includes stage II, stage III, and stage IV.
The staging system used for thymomas is sometimes used for thymic carcinomas.
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.
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. Before starting treatment, patients may want to think about taking part in a clinical trial. 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.
Clinical trials are taking place in many parts of the country. Information about ongoing clinical trials is available from the NCI Web site. Choosing the most appropriate cancer treatment is a decision that ideally involves the patient, family, and health care team.
Three types of standard treatment are used: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 increase the chances of a cure, is called adjuvant therapy.
Radiation therapyRadiation 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.
Hormone therapyHormone 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.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 spinal column, 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.
This summary section refers to specific treatments under study in clinical trials, but it may not mention every new treatment being studied. Information about ongoing clinical trials is available from the NCI Web site.
Treatment of noninvasive thymoma and thymic carcinoma may include the following:
Check for clinical trials from NCI's PDQ Cancer Clinical Trials Registry that are now accepting patients with noninvasive thymoma and thymic carcinoma.
Treatment of invasive thymoma and thymic carcinoma that may be completely removed by surgery includes the following:
Treatment of invasive thymoma and thymic carcinoma that cannot be removed completely by surgery includes the following:
This summary section refers to specific treatments under study in clinical trials, but it may not mention every new treatment being studied. Information about ongoing clinical trials is available from the NCI Web site.
Check for clinical trials from NCI's PDQ Cancer Clinical Trials Registry that are now accepting patients with invasive thymoma and thymic carcinoma.
Treatment of recurrent thymoma and thymic carcinoma may include the following:
This summary section refers to specific treatments under study in clinical trials, but it may not mention every new treatment being studied. Information about ongoing clinical trials is available from the NCI Web site.
Check for clinical trials from NCI's PDQ Cancer Clinical Trials Registry that are now accepting patients with recurrent thymoma and thymic carcinoma.
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