What does stage of a cancer mean?

The stage of a cancer is how much cancer there is and how far it has spread in your body. Your healthcare provider uses exams and tests to find out the size of the cancer and where it is. Scans can also show if the cancer has grown into nearby areas and if it has spread to other parts of your body. The stage of a cancer is one of the most important things to know when deciding how to treat the cancer.

Anal cancer starts in the inner lining of the anus. As anal cancer grows, it can grow through the layers of the wall of the anus. Then, like all cancers, it can spread ( metastasize) to other parts of the body.

The TNM system for anal cancer

The most commonly used system to stage anal cancer is the TNM system from the American Joint Committee on Cancer. Ask your healthcare provider to explain the stage of your cancer to you in a way you can understand.

The first step in staging is to find the value for each part of the TNM system. Here's what the letters stand for in the TNM system:

• T tells how far the main tumor has spread into the lining of your anus and nearby tissue.

• N tells if the lymph nodes in the area of the primary (main) tumor have cancer in them.

• M tells if the cancer has spread ( metastasized) to distant organs in the body, like the liver or lungs.

A number or letter after T, N, and M provide more details about each of these factors. There are also 2 other values that can be assigned:

• X means the provider does not have enough information to tell the extent of the main tumor (TX), or if the lymph nodes have cancer cells in them (NX).

• 0 means no sign of cancer, such as no sign of the primary tumor (T0).

What are the stage groupings of anal cancer?

The T, N, and M values from the TNM system are used to put these cancers into stage groupings. These groupings give an overall description of your cancer. A stage grouping is listed as a Roman numeral and can have a value of I (1), II (2), III (3), or IV (4). The higher the number, the more advanced the cancer is.

These are the stage groupings of anal cancer and what they mean:

Stage 0. The cancer is found only in the top layer of the lining of anal tissue. This stage might also be called anal carcinoma in situ or high-grade squamous intraepithelial lesion (HSIL).

Stage I. The tumor is 2 centimeters (cm), or about 1 inch, across or smaller. It hasn't spread to lymph nodes or other organs.

Stage II. The cancer hasn't spread to other organs. This stage is divided into 2 groups:

• Stage IIA. The cancer is more than 2 cm but less than 5 cm across. The cancer has not spread to nearby lymph nodes.

• Stage IIB. The cancer is more than 5 cm across. It has spread to lymph nodes near the rectum.

Stage III. The cancer has not spread to organs in other parts of the body. This stage is further divided into 3 groups:

• Stage IIIA. Is 1 of these:

  • The tumor is larger than 5 cm across. It has not spread to nearby lymph nodes.

  • The tumor is more than 5 cm and has spread to lymph nodes near the rectum.

• Stage IIIB. The tumor is any size and has spread to nearby organs, such as the vagina, prostate, or bladder. It hasn't spread to nearby lymph nodes.

• Stage IIIC. The tumor is any size and has spread to nearby organs, such as the vagina, prostate, or bladder. It has spread to lymph nodes near the rectum.

Stage IV. The cancer can be any size. It may have spread to nearby lymph nodes or organs. It has spread to distant organs in other parts of the body, such as the liver or lungs.

Talking with your healthcare provider

Once your cancer is staged, talk with your healthcare provider about what the stage means for you. Ask any questions and talk about your concerns.