Stage 0: Is also called carcinoma in situ. Carcinoma in situ means that cancer cells are present but, they are all contained in a small area in the top layer of skin. (epidermis) They have not started to spread or grow into deeper layers of skin. Squamous cell stage 0 is also called Bowen’s disease. If it is not treated it can develop into skin cancer.

Stage 1: The cancer is less than 2 cm and has not spread.

Stage 2: The caner is more than 2 cm across and has not spread.

Stage 3: The cancer has spread into the tissues under the skin and possibly to nearby lymph nodes.

Stage 4: The cancer has spread to another part of the body. This very rarely occurs with either squamous or basal cell cancers of the skin.