Key Points
                    - After laryngeal cancer has been diagnosed, tests are done to find out if cancer cells have spread within the larynx 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 laryngeal cancer:         - Stage 0 (Carcinoma in Situ)     - Stage I     - Stage II     - Stage III     - Stage IV
                
                
                    After laryngeal cancer has been diagnosed, tests are done to find out if cancer cells have spread within the larynx or to other parts of the body.
                    The process used to find out if cancer has spread within the larynx 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 of the disease in order to plan treatment. The results of some of the tests used to diagnose laryngeal cancer are often also used to stage the disease.
                
                
                    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 laryngeal cancer spreads to the lung, the cancer cells in the lung are actually laryngeal cancer cells. The disease is metastatic laryngeal cancer, not lung cancer.
                
                
                    The following stages are used for laryngeal cancer:
                    Stage 0 (Carcinoma in Situ)    In stage 0, abnormal cells are found in the lining of the larynx. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.       Stage I    In stage I, cancer has formed. Stage I laryngeal cancer depends on where cancer began in the larynx:            -  Supraglottis: Cancer is in one area of the supraglottis only and the vocal cords can move normally.     -  Glottis: Cancer is in one or both vocal cords and the vocal cords can move normally.     -  Subglottis: Cancer is in the subglottis only.              Stage II    In stage II, cancer is in the larynx only. Stage II laryngeal cancer depends on where cancer began in the larynx:            -  Supraglottis: Cancer is in more than one area of the supraglottis or surrounding tissues.     -  Glottis: Cancer has spread to the supraglottis and/or the subglottis and/or the vocal cords cannot move normally.     - Subglottis: Cancer has spread to one or both vocal cords, which may not move normally.               Stage III     Stage III laryngeal cancer depends on whether cancer has spread from the supraglottis, glottis, or subglottis.    In stage III cancer of the supraglottis:            -  cancer is in the larynx only and the vocal cords cannot move, and/or cancer is in tissues next to the larynx. Cancer may have spread to one lymph node on the same side of the neck as the original tumor and the lymph node is 3 centimeters or smaller; or     - cancer is in one area of the supraglottis and in one lymph node on the same side of the neck as the original tumor; the lymph node is 3 centimeters or smaller and the vocal cords can move normally; or     - cancer is in more than one area of the supraglottis or surrounding tissues and in one lymph node on the same side of the neck as the original tumor; the lymph node is 3 centimeters or smaller.           In stage III cancer of the glottis:            - cancer is in the larynx only and the vocal cords cannot move, and/or cancer is in tissues next to the larynx; cancer may have spread to one lymph node on the same side of the neck as the original tumor and the lymph node is 3 centimeters or smaller; or     - cancer is in one or both vocal cords and in one lymph node on the same side of the neck as the original tumor; the lymph node is 3 centimeters or smaller and the vocal cords can move normally; or     - cancer has spread to the supraglottis and/or the subglottis and/or the vocal cords cannot move normally. Cancer has also spread to one lymph node on the same side of the neck as the original tumor and the lymph node is 3 centimeters or smaller.           In stage III cancer of the subglottis:            - cancer is in the larynx and the vocal cords cannot move; cancer may have spread to one lymph node on the same side of the neck as the original tumor and the lymph node is 3 centimeters or smaller; or     - cancer is in the subglottis and in one lymph node on the same side of the neck as the original tumor; the lymph node is 3 centimeters or smaller; or     - cancer has spread to one or both vocal cords, which may not move normally. Cancer has also spread to one lymph node on the same side of the neck as the original tumor and the lymph node is 3 centimeters or smaller.              Stage IV     Stage IV is divided into stage IVA, stage IVB, and stage IVC. Each substage is the same for cancer in the supraglottis, glottis, or subglottis.            - In stage IVA:                   - cancer has spread through the thyroid cartilage and/or has spread to tissues beyond the larynx such as the neck, trachea, thyroid, or esophagus. Cancer may have spread to one lymph node on the same side of the neck as the original tumor and the lymph node is 3 centimeters or smaller; or       - cancer has spread to one lymph node on the same side of the neck as the original 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 anywhere in the neck with none larger than 6 centimeters. Cancer may have spread to tissues beyond the larynx, such as the neck, trachea, thyroid, or esophagus. The vocal cords may not move normally.                 - In stage IVB:                   -  cancer has spread to the space in front of the spinal column, surrounds the carotid artery, or has spread to parts of the chest. Cancer may have spread to one or more lymph nodes anywhere in the neck and the lymph nodes may be any size; or       -  cancer has spread to a lymph node that is larger than 6 centimeters and may have spread as far as the space in front of the spinal column, around the carotid artery, or to parts of the chest. The vocal cords may not move normally.                - In stage IVC, cancer has spread to other parts of the body, such as the lungs, liver, or bone.