People who have had a colonoscopy in the past decade are less likely to be diagnosed with advanced colon cancer than those who haven't been screened recently, according to a new study.

Researchers found less-invasive tests, known as sigmoidoscopies, were also tied to a lower risk of advanced tumors -- but only those growing in one side of the colon.

It's still not clear what that means for cancer survival, according to Dr. Chyke Doubeni, who led the new study at the University of Pennsylvania's Perelman School of Medicine in Philadelphia. But while researchers wait for results from more controlled, long-term trials, the new report is more evidence that screening in general is beneficial, they said.

A French doctor performs a colonoscopy on a patient at the Ambroise Pare hospital in Marseille, France.
A French doctor performs a colonoscopy on a patient at the Ambroise Pare hospital in Marseille, France. (Reuters/Jean-Paul Pelissier)

"There's a variety of screening tests for us to choose from," Doubeni told Reuters Health.

"This study doesn't show that colonoscopy is the only test, but it does show that colonoscopy has the advantage in being able to see the right side (of the colon) unlike sigmoidoscopy and fecal occult blood testing."

The U.S. Preventive Services Task Force, a government-backed panel, recommends people between age 50 and 75 get screened for colon cancer using regular fecal occult blood testing, sigmoidoscopy or colonoscopy. The suggested interval between screenings depends on the method - from blood tests every year to colonoscopy every ten years.

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