This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science
This page was updated on June 23, 2022.
Making an informed treatment decision begins with the stage, or progression, of the disease. The stage of skin cancer is one of the most important factors in evaluating treatment options. Non-melanoma skin cancers, such as basal cell carcinomas rarely spread and may not be staged. The chance that squamous cell carcinomas will spread is slightly higher.
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The American Joint Committee on Cancer has developed a uniform system for characterizing the stages of skin cancer. This system allows doctors to determine how advanced a skin cancer is, and to share that information with one another in a meaningful way. This system, known as the TNM staging system, is composed of the three key pieces of information listed below.
T (tumor): This describes the tumor’s size, location and how deep it has grown into the skin.
N (node): This indicates whether or not cancer cells have spread to nearby lymph nodes, or the channels connecting the lymph nodes.
M (metastasis): This refers to whether the cancer cells have spread to distant organs or other parts of the body.
Certain features may increase the risk of the cancer spreading or recurring, and these may also be used to stage basal cell carcinomas. These include:
After the TNM components and risk factors have been established, the cancer is given a stage. For basal cell carcinoma staging, the factors are grouped and labeled 0 to 4. The characteristics and stages of basal cell carcinoma are listed below.
Also called carcinoma in situ, cancer discovered in this stage is only present in the epidermis (upper layer of the skin) and has not spread deeper to the dermis.
In stage 1, the cancer is less than 2 centimeters, about 4/5 of an inch across, has not spread to nearby lymph nodes or organs, and has one or fewer high-risk features.
In stage 2, the cancer is larger than 2 centimeters across, and has not spread to nearby organs or lymph nodes, or a tumor of any size with two or more high-risk features.
In stage 3, the cancer has spread into facial bones or one nearby lymph node, but not to other organs.
In stage 4, the cancer can be any size and has spread (metastasized) to one or more lymph nodes which are larger than 3 cm and may have spread to bones or other organs in the body.
As with basal cell carcinoma, certain features of squamous cell carcinoma raise the risk that the cancer will spread or recur, and those factors are often key in determining the stage of squamous cell carcinomas. These features include:
After the TNM components and risk factors have been established, the cancer is assigned to one of the five squamous cell carcinoma stages, which are labeled 0 to 4. The characteristics and stages of squamous cell cancer are listed below.
Also called carcinoma in situ, cancer discovered in this stage is only present in the epidermis (upper layer of the skin) and has not spread deeper to the dermis. This stage of squamous cell carcinoma is also called Bowen's disease of the skin, which appears as red or pink scaly patches, mostly on skin that's often exposed to the sun.
In stage 1, the cancer is less than 2 centimeters, about 4/5 of an inch across, has not spread to nearby lymph nodes or organs, and has one or fewer high-risk features.
In stage 2, the cancer is larger than 2 centimeters across, and has not spread to nearby organs or lymph nodes, or a tumor of any size with two or more high risk features.
In stage 3, the cancer has spread into facial bones or one nearby lymph node, but not to other organs.
In stage 4, the cancer can be any size and has spread (metastasized) to one or more lymph nodes which are larger than 3 cm and may have spread to bones or other organs in the body.
Treatment options vary depending on the stage of skin cancer. They can range from topical treatments applied directly to the skin for early-stage cancers to more internal treatments such as radiation, chemotherapy and surgery for advanced-stage cancers.
Doctors generally recommend the least invasive regimens appropriate for a particular case, in an attempt to reduce side effects and maintain quality of life as much as possible during treatment.
Beyond stage, other factors that may affect skin cancer treatment decisions include:
In general, stage 0 squamous or basal cell cancers may be removed via a surgical procedure or destroyed using other noninvasive methods, such as topical chemotherapy sometimes combined with photodynamic therapy (light therapy).
If surgery is needed, procedures for basal cell and squamous cell skin cancers most often include:
Cryosurgery: A device is used to freeze and kill cancer cells
Simple excision: The tumor and the surrounding skin are cut away
Mohs micrographic surgery: Layers of the skin are removed in stages while the cells are tested to make sure all of the cancer is removed
Curettage and electrodesiccation (electrosurgery): A spoon-shaped knife scoops away the cancerous cells and surrounding tumor, then electricity is used to further destroy cancer cells and stop bleeding
If the tumor is large or has spread to lymph nodes, bones or other organs, systemic treatments can help destroy more cancer cells beyond the tumor. These typically include those listed below.
Radiation therapy: High-energy X-rays destroy cancer cells
Immunotherapy: Biological treatments help the patient's immune system harm cancer cells
Targeted therapy: Drugs target specific cancer cells in the body
Systemic chemotherapy (which involves administering drugs to destroy fast-growing cancer cells), is rarely used for basal cell carcinomas, but in some cases, it may be recommended after other therapies for patients with advanced squamous cell skin cancer.
Other types of skin cancer may have their own staging systems. Learn about Merkel cell carcinoma and melanoma stages.
Identifying the stage of cancer not only helps the care team determine a treatment plan, it also helps predict a potential prognosis. This is achieved by calculating the percentage of people with skin cancer who survive five years or more after diagnosis compared to people who don’t have that type of cancer. It’s important to remember that this is only a statistic based on all people with skin cancer several years in the past, so individual patient experiences may vary.
Five-year relative survival rates differ depending on the type and stage of skin cancer, but are generally grouped by whether the cancer is localized, regional or distant. Below are the available overall five-year relative survival rates.
Basal cell carcinoma: According to the American Cancer Society (ACS), survival statistics are unavailable for this type of skin cancer. Learn more about basal cell carcinoma survival rates and statistics.
Melanoma: According to the ACS, the overall five-year relative survival rate is 94 percent. Learn more about melanoma survival rates.
Merkel cell carcinoma: According to the ACS, the overall five-year relative survival rate is 65 percent. Learn more about Merkel cell carcinoma survival rates.
Squamous cell carcinoma: According to the Canadian Cancer Society, the overall five-year relative survival rate is 95 percent. Learn more about available information on US squamous cell carcinoma survival rates and statistics.
Keep in mind that the survival rate for skin cancer depends on a variety of factors, including the patient’s age, overall health and the extent of the disease, so always talk to the care team about the patient’s individual prognosis.
Next topic: How is skin cancer diagnosed?