In most cases, nonmelanoma skin cancer is confined to your skin and is easily treated and cured. If skin cancer has spread, then your doctor will want to know the extent or stage of the cancer. This helps your doctor decide whether you need more treatment, and if so, which treatments might be best.
The stage is based on the size of your tumor, how deeply into your skin it has grown, and whether the cancer has spread beyond the tumor to the lymph nodes or other parts of your body. Your doctor will look at the results of biopsies to determine the stage. If you have squamous cell carcinoma, your doctor may also test lymph nodes near the tumor to see if the cancer has spread beyond the skin.
Stages are numbered in Roman numerals between 0 and IV.
Stage 0. Cancer is found only in the original tumor in your skin. It is only in the top layer (epidermis) and has not spread to the dermis. Stage 0 is also called carcinoma in situ.
Stage I. The tumor is 2 centimeters wide or smaller and has no more than one risk feature (see below). Cancer does not invade the bone and has not spread to your lymph nodes or other organs.
Stage II. The tumor is larger than 2 centimeters or it has two or more high-risk features (see below). Cancer does not invade the bone and has not spread outside the skin.
Stage III. The cancer has spread to your facial bones, such as your jaw or bones around you eye. Or it has spread to one nearby lymph node on the same side of your body as the tumor. It is not larger than 3 centimeters wide and has not spread to distant organs.
Stage IV. The cancer can be any size. It has grown into other bones; into more than one lymph node, or into a lymph node larger than 3 centimeters wide, or on the other side of your body; or it has spread to other parts of your body.
High-risk features for nonmelanoma skin cancer include:
The tumor is thicker than 2 millimeters.
The tumor has spread into the lower layer of your dermis, or into the subcutis (Clark level IV or V).
The tumor has grown and spread along nerve pathways.
The tumor began on an ear or on a lip that has hair on it.
The tumor cells look very abnormal under a microscope.
Most nonmelanoma skin cancers are Stage 0 or Stage I. Stage III and IV are relatively rare. Based on your type of cancer, its stage, your overall health, and other factors, your doctor works with you to develop a treatment plan.