How is the stage of skin cancer determined?

The staging of skin cancer depends on the type of cancer. Basal cell carcinoma, the most common form of skin cancer, does not typically spread or metastasize beyond the dermis. However, for more advanced forms of basal cell cancer a staging system of 0-IV exists. Stage 0 involves only the dermis, Stage I is less than 2 centimeters (cm) and does not include lymph nodes or other organs. Stage II likewise does not involve lymph nodes or other organs but is greater than 2cm. Stage III has spread to lymph nodes but does not include other organ involvement. Stage IV can be any size and includes involvement of organs.

Squamous cell carcinoma uses similar staging but follows the TNM staging system, which differentiates T for tumor, N for lymph node involvement and M for metastases. Other less common forms of cancer include melanoma and Merkel cell carcinoma, for which alternative staging systems exist. Melanoma may use the Breslow, Clark, TNM staging or American Joint Committee on Cancer (AJCC) groupings. Merkel cell may likewise use AJCC groupings or alternative staging such as staging defined by the Memorial Sloan Kettering Cancer Center.

If the biopsy shows that you have cancer, your doctor needs to know the extent (stage) of the disease. In very few cases, the doctor may check your lymph nodes to stage the cancer.

The stage is based on:

The size of the growth How deeply it has grown beneath the top layer of skin Whether it has spread to nearby lymph nodes or to other parts of the body.

This answer is based on source information from the National Cancer Institute.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.