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A Cleaner Colon Is Key to Effective Screening

A Cleaner Colon Is Key to Effective Screening

Proper bowel cleaning before a colonoscopy makes it easier to spot precancerous polyps, and avoid costly repeat tests, says a new study.

Photo of man shaking hands with his doctor

The success of the bowel "prep" depends largely on individual patients, who have to carefully follow instructions about taking medication at home in liquid or tablet form that causes diarrhea, thereby emptying the colon.

Effective prepping of the bowel, while unpleasant, is necessary for a successful screening. If patients don't follow the instructions on the bowel-prep medications, and avoid certain foods before the colonoscopy, it becomes more difficult for doctors to spot and remove precancerous growths (adenomas) before they turn into cancer. Because colorectal cancer develops slowly over time, effective screening and early detection of the disease are critical for a patient's survival.

Missed cancers

The researchers found that 42 percent of all adenomas and 27 percent of advanced adenomas were missed because of poor bowel prep. Because of that, "follow-up examination within one year should be considered," says study lead author Benjamin Lebwohl, M.D., at Columbia University Medical Center in New York City.

In conducting the study, researchers reviewed the bowel preparation quality of 12,787 patients who underwent colonoscopy at Columbia University Medical Center over the course of roughly two years. They found preparation quality was either poor or fair for 24 percent - or about 3,000 - of the patients.

Among those with inadequate bowel preparation, 17 percent needed a repeat colonoscopy within three years. The repeat procedures (with proper bowel preparation) uncovered 198 precancerous polyps. Of those polyps, 83 were only spotted during the follow-up colonoscopy -- revealing a miss rate of 42 percent.

For the colonoscopies repeated in less than one year, the miss rate for adenomas was 35 percent, and for advanced adenomas, 36 percent, the researchers say.

The American Cancer Society recommends colonoscopy screening every 10 years, starting at age 50. If you have certain risk factors, you may need to start screening at an earlier age or be screened more often.

Always talk with your health care provider to find out more information.

Online Resources

(Our Organization is not responsible for the content of Internet sites.)

American Cancer Society - What Is Colorectal Cancer?

CDC – Colorectal Cancer Screening

National Cancer Institute – Colon and Rectal Cancer

August 2011

Colorectal Cancer Facts

Colorectal cancer consists of malignant cells found in the colon or rectum, which are parts of the large intestine, which is part of the digestive system. Because colon cancer and rectal cancer have many features in common, they are sometimes referred to together as colorectal cancer.

The exact cause of most colorectal cancer is unknown, but researchers have identified several risk factors:

  • Most people who have colorectal cancer are older than 50, and African-Americans have the highest risk.

  • Certain medical conditions can increase the risk for this cancer, including polyps, which are benign growths on the wall of the colon or rectum; ulcerative colitis, or Crohn's disease; type 2 diabetes; and inherited syndromes such as familial adenomatous polyposis or hereditary nonpolyposis colon cancer.

  • People who have a history of colorectal cancer or polyps, and people with a strong family history of colorectal cancer or polyps also have a higher risk.

  • Lifestyle habits can also increase your risk. Colorectal cancer is often associated with a diet high in red and processed meats. Obesity, physical inactivity, heavy alcohol consumption, and smoking all play a role as well.

Early detection is important for surviving colorectal cancer. Your doctor can explain which screening options may be right for you.

Always talk with your health care provider to find out more information.