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About staging and grading bowel cancer

The stage of bowel (colon and rectal) cancer tells you how big it is and whether it has spread. The grade means how abnormal the cancer cells look under the microscope.

Doctors use different systems to stage bowel cancer. 


You have tests and scans to diagnose your cancer. These tests also give information about the size of your cancer and whether it has spread (the stage). But sometimes doctors can't be certain about the stage of your cancer until after surgery.  

Your treatment depends on what stage of cancer you have. 

There are different ways of staging bowel cancer. There is a number staging system, the TNM system and the Dukes' staging system.


The grade of a cancer tells you how much the cancer cells look like normal cells. This gives your doctor an idea of how your cancer might behave and what treatment you need.

The grades of bowel cancer cells are from 1 to 4:

  • grade 1 (low grade) look most like normal cells
  • grade 2 look a bit like normal cells
  • grade 3  look very abnormal and not like normal cells
  • grade 4 looks completely different from normal cells (high grade)

A low grade cancer is likely to be slower growing and less likely to spread than high grade cancers. 

Last reviewed: 
03 Jul 2018
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