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.
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.
- 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 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.
In stage II, cancer has spread through the capsule and into the fat around the thymus or into the lining of the chest cavity.
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 is divided into stage IVA and stage IVB, depending on where the cancer has spread.
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.