user: What are the stages of Salivary Gland Cancer ?

assistant: Key Points
                    - After salivary gland cancer has been diagnosed, tests are done to find out if cancer cells have spread within the salivary gland or to other parts of the body.     - There are three ways that cancer spreads in the body.    - Cancer may spread from where it began to other parts of the body.    - The following stages are used for major salivary gland cancers:         - Stage I     - Stage II     - Stage III     - Stage IV
                
                
                    After salivary gland cancer has been diagnosed, tests are done to find out if cancer cells have spread within the salivary gland or to other parts of the body.
                    The process used to find out if cancer has spread within the salivary glands or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment. The following procedures may be used in the staging process:         -   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. This procedure is also called nuclear magnetic resonance imaging (NMRI).    -   CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, 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.
                
                
                    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 salivary gland cancer spreads to the lung, the cancer cells in the lung are actually salivary gland cancer cells. The disease is metastatic salivary gland cancer, not lung cancer.
                
                
                    The following stages are used for major salivary gland cancers:
                    Stage I    In stage I, the tumor is in the salivary gland only and is 2 centimeters or smaller.        Stage II    In stage II, the tumor is in the salivary gland only and is larger than 2 centimeters but not larger than 4 centimeters.       Stage III    In stage III, one of the following is true:            - The tumor is not larger than 4 centimeters and has spread to a single lymph node on the same side as the tumor and the lymph node is 3 centimeters or smaller.     - The tumor is larger than 4 centimeters and/or has spread to soft tissue around the affected gland. Cancer may have spread to a single lymph node on the same side as the tumor and the lymph node is 3 centimeters or smaller.              Stage IV     Stage IV is divided into stages IVA, IVB, and IVC as follows:            -  Stage IVA:                  - The tumor may be any size and may have spread to soft tissue around the affected gland. Cancer has spread to a single lymph node on the same side as the tumor and the lymph node is larger than 3 centimeters but not larger than 6 centimeters, or has spread to more than one lymph node on either or both sides of the body and the lymph nodes are not larger than 6 centimeters; or       - Cancer has spread to the skin, jawbone, ear canal, and/or facial nerve, and may have spread to one or more lymph nodes on either or both sides of the body. The lymph nodes are not larger than 6 centimeters.                -  Stage IVB:                  - The tumor may be any size and may have spread to soft tissue around the affected gland. Cancer has spread to a lymph node larger than 6 centimeters; or       - Cancer has spread to the base of the skull and/or the carotid artery, and may have spread to one or more lymph nodes of any size on either or both sides of the body.                -  Stage IVC:                  - The tumor may be any size and may have spread to soft tissue around the affected gland, to the skin, jawbone, ear canal, facial nerve, base of the skull, or carotid artery, or to one or more lymph nodes on either or both sides of the body. Cancer has spread to distant parts of the body.                       Salivary gland cancers are also grouped by grade. The grade of a tumor tells how fast the cancer cells are growing, based on how the cells look under a microscope. Low-grade cancers grow more slowly than high-grade cancers.     Minor salivary gland cancers are staged according to where they were first found in the body.