Colon polyps are most often diagnosed during a colonoscopy or flexible sigmoidoscopy. These tests are very effective when screening for colorectal polyps and for colorectal cancer. If polyps are found during a screening, the provider may remove them immediately or take tissue samples, called biopsies, for analysis in the lab.

There are different types of polyps. Most noncancerous polyps are hyperplastic polyps. The polyps that can more often develop into cancer are known as adenomatous polyps. Although most polyps do not lead to cancer, if they are allowed to grow and are not removed, the danger that they will become cancerous increases with time.