The oral cavity and oropharynx contain several types of tissue and each of these tissues contains several types of cells.
Different cancers can develop from each kind of cell.
The differences are important, because they influence treatment options and outlook for recovery. Squamous cell cancer begins as a collection of abnormal squamous cells. The earliest form of squamous cell cancer is called carcinoma in situ meaning that the cancer cells are present only in the lining layer of cells called the epithelium. Invasive squamous cells cancer means that the cancer cells have spread beyond this layer into deeper layers of the oral cavity or oropharynx. This is the same type of information that is available to physicians and other health care professionals.