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Anal Cancer Treatment

Stages of Anal Cancer

After anal cancer has been diagnosed, tests are done to find out if cancer cells have spread within the anus or to other parts of the body.

The process used to find out if cancer has spread within the anus or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment. The following tests may be used in the staging process:

There are three ways that cancer spreads in the body.

The three ways that cancer spreads in the body are:

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The following stages are used for anal cancer:

Stage 0 (Carcinoma in Situ)

In stage 0, abnormal cells are found in the innermost lining of the anus. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.


Pea, peanut, walnut, and lime show tumor sizes.
Pea, peanut, walnut, and lime show tumor sizes.

Stage I

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

Stage II

In stage II, the tumor is larger than 2 centimeters.

Stage IIIA

In stage IIIA, the tumor may be any size and has spread to either:

Stage IIIB

In stage IIIB, the tumor may be any size and has spread:

Stage IV

In stage IV, the tumor may be any size and cancer may have spread to lymph nodes or nearby organs and has spread to distant parts of the body.