First colonoscopy a real lifesaver

Oct 17 2007

Researchers say the first colonoscopy a patient has can be very, very important.

They say initially clearing the colon of precancerous polyps can reduce the risk of dying from colon cancer by 90%.

The scientists from Memorial Sloan-Kettering Cancer Center's department of epidemiology and biostatistics in New York City, say this first clean out of precancerous polyps significantly reduces deaths from colon cancer even if there are no follow-up examinations.

The researchers led by Dr.Ann G. Zauber, who is a biostatistician, conducted a study over a 20 year period on data of more than 2,602 men and women from the National Polyp Study; they found that removing potentially precancerous growths greatly reduced colon cancer mortality.

The National Polyp study had tracked the development of polyps and invasive colorectal cancer following a first-time colonoscopy.

By using sophisticated mathematical modeling the research team found the risk of dying from colon cancer was about 90% lower if people had both the initial and follow-up procedures than if they underwent neither.

But Dr. Zauber says over the first 10 years, 90% of that effect was due to the initial exam and over the next 10 years, 55% of the effect was still due to the initial procedure.

Dr. Zauber says the surveillance colonoscopies had more of an effect in the second decade than in the first, but the initial procedure was the one which had the biggest effect.

The researchers say the new findings suggest that too much reliance on follow-up screenings which strain health-care resources while exposing patients to risks associated with any invasive procedure, may be unjustified.

Zauber says the new findings should not alter current American College of Gastroenterology recommendations that high-risk patients such as those with a previous history of colon cancer or polyps should undergo follow-up colonoscopies every three to five years.

The findings were presented at the annual meeting of the American College of Gastroenterology (ACG).