In a new landmark study, colonoscopies did not meet the expectations of doctors, gastroenterologists or cancer researchers. In the study, the colonoscopy did not significantly reduce colon cancer mortality and only cut colon cancer risk by one fifth, which is far below the current estimates for the test's efficacy.

"Maybe colonoscopy isn't as good as we always thought … I think we were all expecting colonoscopy to do better," said Samir Gupta, a gastroenterologist at the University of California, San Diego. Dr. Gupta worked on a randomized trial that compared real-life outcomes of people who underwent colonoscopy screening and those who didn't. It turns out that colonoscopies are not as necessary, not as important as they are currently advertised.

Colonoscopy fails to meet expectations in real life, decade-long, study

A colonoscopy is a screening operation that inserts a camera up the rectum. The camera searches for pre-cancerous polyps, known as adenomas. Currently, the colonoscopy is regarded as a gold standard for the prevention of colorectal cancer. Research previously showed that the colonoscopy was responsible for a 70 percent reduction in colon cancer incidence and mortality, but none of this research included any large randomized trials to show real life results.

The medical consensus recommends every person get screened at least once every decade after age 45-50. Michael Bretthauer, a gastroenterologist and researcher in Norway helped lead the study. He said the medical consensus believed that colorectal cancer would become "extinct" if everyone got screened at least once every decade. But colon cancer continues to plague the population, no matter how many times a polyp is detected and removed.