What are the stages of Hypopharyngeal Cancer ? 

Key Points
                    - After hypopharyngeal cancer has been diagnosed, tests are done to find out if cancer cells have spread within the hypopharynx 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 hypopharyngeal cancer:         - Stage 0 (Carcinoma in Situ)     - Stage I     - Stage II     - Stage III     - Stage IV
                
                
                    After hypopharyngeal cancer has been diagnosed, tests are done to find out if cancer cells have spread within the hypopharynx or to other parts of the body.
                    The process used to find out if cancer has spread within the hypopharynx 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 hypopharyngeal 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 hypopharyngeal cancer spreads to the lung, the cancer cells in the lung are actually hypopharyngeal cancer cells. The disease is metastatic hypopharyngeal cancer, not lung cancer.
                
                
                    The following stages are used for hypopharyngeal cancer:
                    Stage 0 (Carcinoma in Situ)    In stage 0, abnormal cells are found in the lining of the hypopharynx. 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 in one area of the hypopharynx only and/or the tumor is 2 centimeters or smaller.       Stage II    In stage II, the tumor is either:            - larger than 2 centimeters but not larger than 4 centimeters and has not spread to the larynx (voice box); or     - found in more than one area of the hypopharynx or in nearby tissues.              Stage III    In stage III, the tumor:            - is larger than 4 centimeters or has spread to the larynx (voice box) or esophagus. Cancer may have spread to one lymph node on the same side of the neck as the tumor and the lymph node is 3 centimeters or smaller; or     - has spread to one lymph node on the same side of the neck as the tumor and the lymph node is 3 centimeters or smaller and cancer is found:                  - in one area of the hypopharynx and/or is 2 centimeters or smaller; or       - in more than one area of the hypopharynx or in nearby tissues, or is larger than 2 centimeters but not larger than 4 centimeters and has not spread to the larynx.                         Stage IV     Stage IV is divided into stage IVA, IVB, and IVC as follows:            - In stage IVA, cancer:                  - has spread to cartilage around the thyroid or trachea, the bone under the tongue, the thyroid, or nearby soft tissue. Cancer may have spread to one lymph node on the same side of the neck as the tumor and the lymph node is 3 centimeters or smaller; or       - has spread to one lymph node on the same side of the neck as the tumor (the lymph node is larger than 3 centimeters but not larger than 6 centimeters) or to lymph nodes anywhere in the neck (affected lymph nodes are 6 centimeters or smaller), and one of the following is true:                           - cancer is found in one area of the hypopharynx and/or is 2 centimeters or smaller; or          - cancer is found in more than one area of the hypopharynx or in nearby tissues, or is larger than 2 centimeters but not larger than 4 centimeters and has not spread to the larynx (voice box); or          - cancer has spread to the larynx or esophagus and is more than 4 centimeters; or          -  cancer has spread to cartilage around the thyroid or trachea, the bone under the tongue, the thyroid, or nearby soft tissue.                                  - In stage IVB, the tumor:                  - has spread to muscles around the upper part of the spinal column, the carotid artery, or the lining of the chest cavity and may have spread to lymph nodes which can be any size; or       - may be any size and has spread to one or more lymph nodes that are larger than 6 centimeters.                - In stage IVC, the tumor may be any size and has spread beyond the hypopharynx to other parts of the body.