Stage 4 is the final stage of Parotid gland cancer means that the cancer is advanced and there are 3 groups within stage 4 salivary gland cancer. It was internally divided to 3 substages which include the following
Stage 4a means that the cancer has grown into the tissues around the salivary gland, the skin, the jawbone, ear canal or facial nerve. And there are cancer cells in the lymph nodes on one or both sides of the neck. These lymph nodes are smaller than 6cm across (2.4 inches). Describes any invasive tumor (T4a), with either no lymph node involvement (N0) or spread to only a single same-sided lymph node (N1), but no metastasis (M0). It is also used for a T3 tumor with one-sided nodal involvement (N1), but no metastasis (M0), or any tumor (any T) with extensive nodal involvement (N2).
Stage 4b means that the cancer has grown into the tissues around the salivary gland, the base of the skull or the main blood vessel in the neck (the carotid artery). There are cancer cells in the lymph nodes on one or both sides of the neck and at least one lymph node is larger than 6cm across. Describes any cancer (any T), with more extensive spread to lymph nodes (N2, N3), but no metastasis (M0).
Stage 4c means that the cancer has spread to another part of the body, such as the lungs. Describes any cancer with distant metastasis (any T, any N, and M1)