Anal Cancer Stages

A cancer’s stage refers to how large the primary tumor is and how far the cancer has spread in the patient’s body. Knowing the stage helps the care team understand the disease and develop an appropriate treatment plan. It also impacts the patient’s prognosis, or chance for a successful treatment.

TNM stages

The TNM staging system is used for most cancers, including non-small cell lung cancer.

TNM staging describes cancer based on three main factors:

• The size of the primary tumor (T) and whether it has invaded nearby tissues.
• The cancer’s spread to nearby lymph nodes (N).
•  Whether the cancer has metastasized (M), or spread, to distant parts of the body.

Each TNM factor is assigned a number that reflects the extent of the cancer. Tumors (T) are scored between 1-4, nodes (N) 1-3, and metastasis (M) 0-1.

After all diagnostic and staging procedures are performed, your doctor should know the TNM stage of your cancer and be able to explain how this stage impacts your treatment and prognosis.

0 to IV stages

Often, TNM staging can be simplified into stages four stages (I-IV). For some cancers, there is also a stage 0. Larger numbers mean the cancer is more advanced and is generally more difficult to treat.

• Stage 0 reflects the presence of abnormal cells that have not spread to tissue that is immediately nearby. Stage 0 is considered precancerous, though it could become cancer in the future. This stage is also called “in-situ,” which means “in its original place.” Not all cancers have a stage 0.
• Stage I cancers are typically small and confined to the area where they began.
• Stage II and Stage III cancers have spread to nearby tissue and/or lymph nodes.
• Stage IV cancer has spread to distant areas of the body. This is also called metastatic cancer. Stage IV cancer often cannot be cured, but frequently can be managed like a chronic disease.

Anal cancer stages

(source: National Cancer Institute)

Stage I anal cancer

In stage I, cancer has formed and the tumor is 2 centimeters or smaller.

Stage II anal cancer

Stage II anal cancer is divided into stages IIA and IIB.

• In stage IIA, the tumor is larger than 2 centimeters but not larger than 5 centimeters.
• In stage IIB, the tumor is larger than 5 centimeters.

Stage III anal cancer

Stage III anal cancer is divided into stages IIIA, IIIB, and IIIC.

• In stage IIIA, the tumor is 5 centimeters or smaller and has spread to lymph nodes near the anus or groin.
• In stage IIIB, the tumor is any size and has spread to nearby organs, such as the vagina, urethra, or bladder. Cancer has not spread to lymph nodes.
• In stage IIIC, the tumor is any size and may have spread to nearby organs. Cancer has spread to lymph nodes near the anus or groin.

Stage IV anal cancer

In stage IV, the tumor is any size. Cancer may have spread to lymph nodes or nearby organs and has spread to other parts of the body, such as the liver or lungs.