Both mechanisms may also act together. As polyps grow they assume a greater risk of becoming malignant. The chance of a very small polyp being cancerous is less than one in five hundred, while the chance for a larger polyp, about one centimeter, is about one in ten. The chance that a large polyp, over two centimeters, is cancerous may be as high as one in two. Although we are not sure what causes polyp growth, researchers believe that the same genetic and lifestyle factors that cause colorectal cancer are involved.
Researchers believe polyps are the most common precursors or cancer of the colon and rectum.
Many polyps develop slowly and are benign for long periods of time. During this benign interval, they can be identified and removed, interrupting the very process that can lead to cancer. A polyp removed is a potential cancer prevented. When a polyp is identified as a risk factor for colorectal cancer, patients can be reassured that regularly scheduled colonoscopic examinations can remove any future polyps and most often lead to the prevention of cancer. At the very least, colon and rectal cancer can be detected at their earliest stages, when a cure is virtually assured.