Squamous Cell Carcinoma Stages / Staging

Cancer staging is the process of finding out how advanced and widespread a cancer has become. Squamous cell carcinomas have a small chance of spreading to other organs in the body, so they will sometimes be staged. This is particularly the case for tumors that have a higher chance of spreading.

The TNM System of Squamous Cell Carcinoma Staging 

The American Joint Commission on Cancer has developed a uniform squamous cell carcinoma staging system that allows doctors to determine how advanced the disease is, and to share that information with each other in a meaningful way. This system, known as the TNM system, is composed of three key pieces of information:

• Tumor (T) describes the tumor’s size, location and how deep it has grown into the skin.
• Nodes (N) indicates whether or not cancer cells have spread to nearby lymph nodes, or the channels connecting the lymph nodes.
• Metastasis (M) refers to whether the cancer cells have spread to distant organs.

In addition, there are certain features that are considered to make the cancer at higher risk for spreading or recurrence, and these may also be used to stage squamous cell carcinomas. These include:

• Greater than 2 mm in thickness
• Invasion into the lower dermis or subcutis layers of the skin
• Invasion into the tiny nerves in the skin
• Location on the ear or on a hair-bearing lip

After the TNM components and risk features have been established, the cancer is assigned to one of the five squamous cell carcinoma stages, which are labeled 0 to IV. The characteristics and stages of squamous cell cancer are:

• Stage 0 Squamous Cell Carcinoma: 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.
• Stage I Squamous Cell Carcinoma: 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.
• Stage II Squamous Cell Carcinoma: 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 2 or more high risk features.
• Stage III Squamous Cell Carcinoma: The cancer has spread into facial bones or 1 nearby lymph node, but not to other organs.
• Stage IV Squamous Cell Carcinoma: The cancer can be any size and has spread (metastasized) to 1 or more lymph nodes which are larger than 3 cm and may have spread to bones or other organs in the body.

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