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Colorectal Cancer Defined

Colorectal cancer (CRC), also known as colon cancer, is cancer that occurs in the colon or rectum. The colon is the large intestine or large bowel. The rectum is the passageway that connects the colon to the anus.

CRC is a slow-growing disease (six to 10 years) that typically begins as a non-cancerous polyp. A polyp is a growth that can become cancer. Frequently, there are no symptoms or discomfort from polyps or early tumors.

CRC is the second leading cancer killer in the United States, but it doesn’t have to be. If both men and women aged 45 years or older had regular screening tests, at least 60% of deaths from this cancer could be avoided. So, if you are age 45 or older, start getting screened now.

The risks for colorectal cancer may be higher than average if:

  • You or a close relative have had a colorectal polyp or colorectal cancer.
  • You have inflammatory bowel disease.
  • You have a genetic syndrome, such as familial adenomatous polyposis
    (FAP) or hereditary nonpolyposis colorectal cancer.

People at high risk for colorectal cancer may need earlier or more frequent tests than other people. Talk to your doctor about when to begin screening and how often you should be tested.

Visit the National Cancer Institute for a detailed description of colorectal cancer terms, risk factors, screening methods, and more.

Page last updated: November 18, 2021