Staging for non-melanoma skin cancer depends on how large and deep the cancer has grown, whether the tumor has certain high-risk features, and whether it’s located on the eyelid. Basal cell skin cancer, the most common skin cancer type, rarely spreads to other parts of the body.
High-Risk features of non-melanoma skin cancer include:
- Tumor is thicker than 2 millimeters
- Tumor has spread into the lower layer of the dermis, or into the layer of fat below the skin
- Tumor has spread along nerve pathways
- Tumor began on an ear or lip that has hair
- Tumor cells look very different from normal cells under a microscope
These stages refer to non-melanoma skin cancers, not located on the eyelid:
- Stage 0: The cancer involves only the epidermis (top or outer layer) of skin. It is called carcinoma in situ. Bowen’s disease is an early form of squamous cell skin cancer that usually looks like a reddish, scaly or thickened patch on the skin. If not treated, the cancer may grow deeper into the skin.
- Stage I: The growth is no larger than 2 centimeters wide (more than three-quarters of an inch or about the size of a peanut). May have one high-risk feature.
- Stage II: The growth is larger than 2 centimeters wide, or is any size with two or more high-risk features.
- Stage III: The cancer has invaded below the skin to cartilage, muscle, or bone, or has spread to the jaw, eye socket or side of skull. Stage III skin cancers are larger than 2 cm across, or they may be smaller with two or more high risk features, plus the involvement of one lymph node on the same side of the body, but the lymph node is no larger than 3 centimeters.
- Stage IV: The cancer has spread one or more lymph nodes, which are larger than 3 cm. Cancer has spread to other places in the body, such as the base of the skull, spine, ribs or lung.
- Stage 0: Abnormal cells are found in epidermis (top or outer skin layer). Also called carcinoma in situ.
- Stage I: Tumor is up to 20 mm in size; cancer cells may have spread to the edge of the eyelid where the lashes are, or through the thickness of the lid.
- Stage II: Tumor is larger than 20 mm or has spread to nearby parts of the eye, eye socket or nerves in the eyelid
- Stage III: Tumor is anywhere in or near the eye and cancer has spread to nearby lymph nodes. Or, In order to remove entire tumor, the whole eye and part of optic nerve must be removed, and possibly bone, muscles, fat and connective tissue. Or, tumor has spread to other facial structure, the brain or cannot be removed surgically.
- Stage VI: Cancer has spread to distant parts of the body.