Mouth cancer can develop on the lips or inside the mouth. Areas where cancerous cells and tumors are often seen are the gums, sides of the cheeks, roof of the mouth and under the tongue. According to the National Cancer Institute, most mouth cancers start in the small, flat cells that are in the lining of the mouth. As the cancer progresses, the cancerous cells grow deeper into other tissues. The progression of mouth cancer is classified into stages, from 0 through IV. If caught in one of the earlier stages, mouth cancer is treatable, and the outlook for the patient is good.
Stage 0
Not many mouth cancers are diagnosed in stage 0, as there are often no symptoms. In stage 0, the cells are simply classified as "abnormal," with a chance that they will develop into cancer. This stage is also referred to as "carcinoma in situ."
Stage I
Stage 1 is the earliest stage of developed cancer cells. In stage 1, the cancerous cells have developed into a small tumor, and the tumor is starting to spread deep into the tissues but has not spread to nearby tissues or other areas of the body. The size of the cancer is between 1 and 2 cm, which is between the size of a pea and a peanut.
Stage II
Stage II mouth cancer simply means the size of the cancer has grown to between 2 and 4 cm, or between the size of a peanut and a walnut. While that is a large-size tumor, the cancerous cells have not spread into the lymph nodes or other parts of the body. This is still considered an early stage of mouth cancer, as the cancerous cells are still contained in one area.
Early Stage III
Some stage III mouth cancers are still considered "early stage" cancers. This is true only if the cancer has grown beyond 4 cm but has not spread to other parts of the body or to any lymph nodes. This is also sometimes referred to as stage IIIA. Other stage III cancers (stage IIIB) are considered advanced cancers, because regardless of whether the tumor has grown in size or not, the cancer has spread into at least one lymph node.
