Staging is the process of finding out how far the cancer has spread. This is very important because your treatment and the outlook for your recovery depend on the stage of your cancer. For early cancer, surgery may be all that is needed. For more advanced cancer, other treatments like chemotherapy or radiation therapy may be used.

There is more than one system for staging colorectal cancer. Some use numbers and others use letters. But all systems describe the spread of the cancer through the layers of the wall of the colon or rectum. They also take into account whether the cancer has spread to nearby organs or to organs farther away.

Stages are often labeled using Roman numerals I through IV (1-4). As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV (4), means a more serious cancer.

There are really 2 types of staging for colorectal cancer. The clinical stage is your doctor's best guess of the extent of your disease, based on the results of the physical exam, biopsy, and any other tests you have had. If you have surgery, your doctors can also figure out the pathologic stage. This stage is based on the same factors as the clinical stage plus what is found during surgery and a biopsy of the tissue.

Because most patients with colorectal cancer have surgery, the pathologic stage is most often used to describe the extent of this cancer. Pathologic staging is likely to be more accurate than clinical staging, as it allows your doctor to get a good look at the extent of your disease.

Grade of colorectal cancer

Another factor that can affect the outlook for survival is the grade of the cancer. Grade is a description of how closely the cancer looks like normal colorectal tissue under a microscope. Low-grade means the tissue looks more normal; high-grade means the tissue looks less normal. Most of the time, the outlook is not as good for high-grade cancers as it is for low-grade cancers.

Last Medical Review: 03/05/2008
Last Revised: 05/07/2009