Small colorectal polyps that grow at follow-up screening are three times more likely to have advanced histology than stable or regressing polyps, show results from the largest longitudinal study of its kind.

US doctors suggest this risk was greater still — 25-fold higher — for small polyps that doubled in volume per year compared to polyps that did not meet this threshold.

Though most small polyps were unlikely to develop advanced histology or cancerous lesions, the University of Wisconsin-led team say their findings supported resection of those that increased in size.

Their study involved some 11,100 patients (mean age 57) who were screened for colorectal polyps from 2004-20, with 1067 people having one to two polyps measuring between 6-9mm.