For more than 20 years, American adults have been told to get colonoscopies beginning in middle age to prevent colon cancer. But evidence supporting colonoscopy has never met the "gold standard" for research trials, so it's been unclear exactly how useful the screening is for preventing cancer and saving lives. A new study in European countries where colonoscopies weren't routinely offered appears to suggest the procedure may be less helpful than many had hoped. But some health experts warn against misinterpreting the study's findings. Swipe for what experts want you to know. Visit the link in bio for more.