Colon and rectal cancer is the second most common cancer in the United States. In 2017, nearly 136,000 new cases of colorectal cancer were expected to be diagnosed in the U.S. About 1 in 20 (5%) Americans will develop colorectal cancer during their lifetime.
Colorectal polyps (benign abnormal growths) affect about 20% to 30% of American adults. Most cases of colorectal cancers develop slowly over many years. We now know that most of colon and rectal cancers start as a polyp — a small growth that starts in the colon or rectum and develops into a cancer. Routine colonoscopies can remove these polyps and prevent colon or rectal cancer.
The American Cancer Society believes that preventing colorectal cancer (and not just finding it early) should be a major reason for getting tested. Screening and diagnostic colonoscopies have the best chance of finding both polyps and colon cancer and should be your first choice if these tests are available to you and you are willing to have them.
Doctors will take into account a number of things when they talk to you about the tests you should have, how often you should have them, and when you should begin testing. Items include whether you are at average, increased, or high risk for colorectal cancer. Your risk will depend on whether you have had polyps, cancer, or certain other diseases, as well as your family history. In general, both men and women at average risk of colorectal cancer should begin screening tests at age 45 – 50.
Colon and rectal cancer is nearly always treated with surgery. Both chemotherapy and radiation therapy may also be required in treatment and this is determined from the location of the tumor, as well as, the stage of the tumor.
American Society of Colon & Rectal Surgeons: Colorectal Cancer