The research included an analysis of more than 2,000 patients between 1980 and 1990, who were referred for initial colonoscopy at National Polyp Study clinical centers. Davila calls the study historical.

 "We knew from previous studies that removal of precancerous polyps resulted in a reduction in the incidence of colorectal cancer, but this is the first time a reduction in mortality has been clearly demonstrated."

Screening prep scares away many
Unfortunately, many people avoid the screening because of the preparation necessary to cleanse the colon. Davila says the fear of getting cancer should outweigh any fears people have to prepare for the procedure.

Davila adds, "The preparation is very important because it helps the physician get a clearer view of the colon. Without good visualization, it is impossible to detect precancerous polyps or other lesions."

Are you at risk?
Guidelines are in place for those considered at average, increased or high risk for colorectal cancer.

Patients at average risk for colorectal cancer should undergo screening starting at age 50.  Average risk patients are those with:

• no history of adenomas or precancerous polyps,
• no history of inflammatory bowel disease and
• no family history of colon cancer.

Patients with a history of adenomas or precancerous polyps are at increased risk. They should undergo surveillance examinations based on the number and characteristics of the polyps removed. Commonly, these patients undergo colonoscopy about every 3-5 years.

Patients at increased risk due to a positive family history should begin screening at age 40 or 10 years before the youngest case in the immediate family. A positive family history includes:

• colorectal cancer or precancerous polyps in a first-degree relative before age 60 or in two or more first-degree relatives of any age, and
• either colorectal cancer or precancerous polyps in a first-degree relative age 60 or older or in two second-degree relatives with colorectal cancer.
  

There are patients at very high risk for colorectal cancer because of the presence of other diseases or genetic conditions. They should be seen by experts in those particular diseases, including:

• genetic diagnosis of familial adenomatous polyposis (FAP) or suspected FAP without genetic testing evidence,
• genetic or clinical diagnosis of hereditary nonpolyposis colorectal cancer or individuals at increased risk of it, and
• a history of inflammatory bowel disease (ulcerative colitis or Crohn's disease).
  

African-Americans may be at higher risk of colorectal cancer and some guidelines would suggest screening starting at age 45.  

In the United States, colorectal cancer is the third most common cancer diagnosed among men and women and the second leading cause of death from cancer. Colorectal cancer can be prevented by the detection and removal of precancerous polyps. "We urge you to get your screening test," Davila says.