One in 20 people will get colon cancer in their lifetime. In fact, colon cancer is the second most common cause of cancer-related deaths in the United States.

But colon cancer can be prevented by regular colonoscopy exams, a visual examination of the colon and rectum performed by a physician.

There are many tests that can detect colon cancer, but only a colonoscopy enables physicians to identify precancerous growths (polyps) and remove them before they develop into cancer.


Colon Cancer, Polyps, and Colonoscopies: Basic Concepts

• Approximately 50 percent of adults over the age of 50 have polyps growing silently in their large intestine (this includes the colon and the rectum).

• Polyps are benign (noncancerous) growths that develop on the inner lining of the colon wall. They start small and grow slowly but have the potential to turn into cancer.

• It is estimated to take between five and 15 years from when a polyp begins for it to grow into cancer.

• A colonoscopy is a procedure that allows a specialized physician (a gastroenterologist) to examine the entire large intestine with a flexible, lighted videoscope. During the colonoscopy, almost all of the polyps that are found can be removed.

• When colon cancer is found, it can be cured 95 percent of the time provided that it is found in its earliest stages.


Most importantly: Removing polyps helps remove the risk of colon cancer developing. In fact, studies have shown that colonoscopies can reduce colon cancer deaths by as much as 90 percent.

Many people have concerns about preparing for the procedure as well as fears about the procedure itself. However, when asked, patients who have had a colonoscopy say that the preparation was not too uncomfortable and the procedure itself was easy because they were sedated.


Screening Options

There are many types of screening exams, such as FIT testing, Cologuard, ColoVantage, CT colonography, and flexible sigmoidoscopy, but a colonoscopy is the only test that can prevent colon cancer as well as detect it in its early stages, when cure rates are about 95 percent.


Who Should Be Screened?

Every adult over 50 years of age should have colon cancer screening performed. It is now recommended that African-American individuals should start screening at age 45.

Although colonoscopy is the preferred screening method in the United States, any screening is better than no screening.

Individuals are considered average risk if they are over 50 years of age (45 years for African-Americans) with no personal or family history of colon polyps or colon cancer, no history of familial polyposis syndromes, and no history of ulcerative colitis or Crohn’s disease.

High-risk individuals are those with a personal or family history of colon cancer or precancerous colon polyps, a history of a familial polyposis syndrome, a personal history of ulcerative colitis, or Crohn’s disease.

High-risk individuals should start screening at age 40 or 10 years younger than the youngest affected family member.

Patients with a personal history of ulcerative colitis or Crohn’s disease or a family history of a familial polyposis syndrome may need to start screening significantly earlier. This should be discussed with your physician.


How is a Colonoscopy Done?

Generally, the physician will ask you to stay on a clear-liquid diet for 24 hours prior to the colonoscopy. A laxative drink will be prescribed, usually to be taken the evening before and the morning of the scheduled procedure.

Sedative medications are given, and most patients sleep through the entire procedure. The visual examination of the colon and rectum takes approximately 20-30 minutes.

Patients generally awaken within a few minutes after the procedure and feel alert and ready to eat within 20-30 minutes.


Even though patients may have concerns about having a colonoscopy, it is the most valuable tool for preventing any form of colon cancer.

When people understand how effective a colonoscopy is in preventing colon cancer and saving lives, they will usually put aside their concerns and reservations and undergo this potentially lifesaving procedure.


Neal M. Shindel, MD, is chief of gastroenterology at PIH Health and director of the Colon Cancer Prevention Alliance in Whittier, Calif. In practice for 32 years, he has performed over 50,000 colonoscopies.

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