There’s been some debate in recent months over how effective colonoscopy really is at saving lives — but new research indicates polyp removal during the procedure can actually cut colon cancer deaths in half.

The largest and longest follow-up of polyp patients ever conducted was recently published in the New England Journal of Medicine, and researcher Ann G. Zauber, PhD, a biostatistician at Memorial Sloan-Kettering Cancer Center in New York City, said the study confirms what has long been suspected but couldn’t previously be proven.

The study involved 2,600 patients who were followed for an average of 16 years after having precancerous colon polyps removed during colonoscopy screenings. The results showed detection and removal of the polyps was associated with a 53 percent reduction in death from colon cancer compared to deaths expected in the general population among people of similar age and gender.

Durado Brooks, MD, MPH, director of the American Cancer Society’s prostate and colorectal cancer division, told WebMD that while the study is encouraging, follow-ups are necessary after polyps are removed. “Colonoscopy is an extraordinary tool, but it is not infallible,” Brooks says. “Once a polyp is found, people need to be rechecked on a regular basis.”

A research team led by Memorial Sloan-Kettering gastroenterologist Dr. Sidney J. Winawer is also conducting trials comparing colonoscopy outcomes with other colorectal cancer screening methods, including annual stool blood testing.

“When I’m asked which test is best, the answer I always give is that the best test is the one that gets done,” he says.

The ACS recommends colorectal cancer screening beginning at age 50 for men and women with an average risk of developing the cancer, and earlier if there’s a family history of the disease.