Stages and Risk Groups of Basal Cell Carcinoma

Staging is the process of figuring out whether cancer has spread, and if so, how far. The stage of a cancer describes how much cancer is in the body. Staging is important for most types of cancer to help determine the best treatment options.

Basal cell carcinoma (BCC), also known as basal cell skin cancer, rarely spreads beyond where it starts, so it often doesn’t need to be staged. Other factors aside from the stage of a BCC can help give an idea of how serious a BCC is likely to be.

Do all basal cell carcinomas need to be staged?

Staging is rarely needed for BCC because these cancers are almost always cured before they spread to other parts of the body.

When staging is done, it is based on the results of physical exams, biopsies, and imaging tests if they are done.

How is the stage determined?

The system most often used to stage basal cell skin cancers is the American Joint Committee on Cancer (AJCC) TNM system.

This staging system applies only to basal cell skin cancers of the head and neck area – the lips, ears, face, scalp, and neck. The stage is based on 3 key pieces of information:

• The size of the tumor (T) and whether it has grown deeper into nearby structures or tissues, such as a bone
• The spread to nearby lymph nodes (N)
• The spread (metastasis, M) to distant parts of the body

Numbers or letters after T, N, and M provide more details about each of these factors. Higher numbers mean the cancer is more advanced.

Once the T, N, and M categories have been determined, this information is combined to assign an overall stage. The earliest stage of skin cancer is stage 0, also called carcinoma in situ, or CIS. The other stages range from I through IV. As a rule, the lower the number, the less the cancer has spread.

If your basal cell skin cancer is in the head and neck area, talk to your doctor about your specific stage. Cancer staging can be complex, so ask your doctor to explain it to you in a way you understand.

To learn more about how cancers are staged, see Cancer Staging.

Risk groups for basal cell carcinoma

The National Comprehensive Cancer Network (NCCN) develops treatment guidelines for cancer care. The NCCN uses certain factors to divide basal cell cancers into risk groups, which can be used to help determine the best treatment options.

BCCs are divided into 2 risk groups based on how likely they are to come back after treatment.

High-risk BCCs

BCCs are at high risk of coming back after treatment if they have any of the following features:

• The tumor is on the trunk (chest or back), arm, or leg (other than the front of the lower leg), and it’s at least 2 cm across.
• The tumor is on any other part of the body (head, neck, hands, feet, or genital area), regardless of size.
• The tumor doesn’t have well-defined borders.
• The tumor is a recurrence, as opposed to a new tumor.
• The tumor is in a place that was previously treated with radiation.
• The tumor has an aggressive growth pattern when seen under a microscope.
• Cancer cells have invaded small nerves in or near the tumor, known as perineural invasion.
• The person with BCC has a weakened immune system.

Low-risk BCCs

BCCs that don’t have any high-risk features are in the low-risk group.

To learn more about how these risk groups might affect your treatment options, see Treating Basal Cell Carcinoma.